Next Article in Journal
Modification and Improvement of the Churchill Equation for Friction Factor Calculation in Pipes
Previous Article in Journal
Degradation of Bisphenol A Using Self-Excited Oscillating Jets in Synergy with Fenton and Periodate Oxidation: Experimental and Artificial Neural Network Modeling Study
 
 
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

A Comprehensive Inventory, Characterization, and Analysis of Rock Glaciers in the Jhelum Basin, Kashmir Himalaya, Using High-Resolution Google Earth Data

by
Tariq Abdullah
1 and
Shakil Ahmad Romshoo
2,3,4,*
1
Department of Planning and Geomatics, Islamic University of Science and Technology, Awantipora 192122, India
2
Islamic University of Science and Technology, Awantipora 192122, India
3
Centre of Excellence for Glacial Studies in the Western Himalaya, University of Kashmir, Srinagar 19000, India
4
Department of Geoinformatics, University of Kashmir, Srinagar 190006, India
*
Author to whom correspondence should be addressed.
Water 2024, 16(16), 2327; https://doi.org/10.3390/w16162327
Submission received: 6 June 2024 / Revised: 12 August 2024 / Accepted: 14 August 2024 / Published: 19 August 2024

Abstract

:
Rock glaciers are crucial freshwater resources, yet detailed knowledge about their distribution, characteristics, and dynamics in the Himalayan region is scarce. This study presents a comprehensive rock glacier inventory of the Jhelum basin, Kashmir Himalaya, India, using high-resolution Google Earth data. We identified 240 rock glaciers covering an area of 41.24 ± 2.2 km2, with ~76% classified as active, ~20% inactive, and 3.7% relict. The average areas and lengths of these rock glacier types were 0.19 km2, 0.06 km2, and 0.29 km2, and 699 m, 426 m, and 952 m, respectively. Most rock glaciers (~90%) were oriented northwards (N, NE, NW), while only 5% faced southwards (S, SE, SW). The lower limit of permafrost in the Jhelum basin is about 3316 m asl. Furthermore, we estimated the ice storage of rock glaciers in the Jhelum basin at 0.80 ± 0.13 km3, equivalent to 0.72 ± 0.12 km3 of water volume. This study enhances our understanding of permafrost distribution and the characteristics and dynamics in the basin. Given their greater resilience to climate change compared to clean glaciers, the hydrological significance of rock glaciers is expected to increase under projected climate change scenarios. This study highlights their importance as a vital water resource amidst the accelerated recession of clean glaciers.

1. Introduction

Snow and glaciers are crucial sources of perennial freshwater [1] for mountain communities worldwide [2,3], especially in dry regions and during dry seasons [2,4,5,6]. High-mountain Asia (HMA), with its numerous glaciers, provides vital freshwater that supports billions of people downstream [7]. Existing glacier studies suggest a rapid retreat of mountain glaciers worldwide [8], largely attributed to anthropogenic activities [9,10]. Over the Himalayan region, enhanced glacier melting with a large intra-regional variation has been reported [11,12]. Recently, Romshoo et al. [13] found that glaciers in the Kashmir Himalaya are retreating faster than those in nearby regions like Nanga Parbat [5], Zanaskar [14], and Ladakh [15,16]. The ongoing retreat and mass loss of glaciers worldwide, especially in HMA, is projected to continue throughout the twenty-first century [9,17,18], posing serious risks to food, water, and energy security [19,20]. Mountain glaciers, excluding those in the Antarctic, are projected to lose about 64% of their volume by the end of the 21st century under the RCP 8.5 emission scenario [21,22], with regions such as Central Europe, Caucasus, Southern Andes, and HMA expected to experience mass losses exceeding 75%. HMA is projected to experience a significant mass loss of ~36% by the end of the 21st century, even if global warming is limited to 1.5 °C above pre-industrial levels [23]. In the short-term, glacier recession leads to increased streamflow; however, once the ‘tipping point’ is reached, melt rates decrease due to glacier shrinkage [24,25], which will cause a gradual decrease in glacier runoff through the end of the 21st century [24]. Most glacierized basins in the HMA region are expected to reach peak streamflow by the mid-21st century under the RCP4.5 climate change scenario [25,26].
Given the projected changes in glaciers, rock glaciers are expected to serve as significant long-term water reservoirs [27,28,29,30] due to their thick supraglacial debris. Unlike clean ice glaciers, they are less susceptible to annual and seasonal variations in meteorological conditions, making them climatically more resilient. Their delayed response to climate change [31,32] further positions rock glaciers as crucial in meeting the increasing water demands in mountainous regions as streamflow from clean ice glaciers diminishes [24,30,33,34,35]. As a result, the hydrological importance of rock glaciers is expected to surpass that of clean ice glaciers in the future [29,33,34].
Despite their hydrological importance, rock glaciers have received relatively little attention globally [7,26,36,37]. This underscores the importance of focusing on rock glaciers, particularly in mountainous regions like the Kashmir Himalaya, where glaciers are receding at a faster rate of 0.75% a−1 compared to the neighboring Ladakh and Karakoram regions [13,38]. Over the past several decades, research has predominantly focused on glacier changes, neglecting other components of the cryosphere like rock glaciers and aufeis [6,39]. Although global attention toward rock glaciers has recently increased, significant data gaps remain in the HMA region. The existing inventories of rock in HMA are sporadic and geographically limited [40,41,42,43,44,45,46], leaving much unknown about their status, distribution, and hydrological significance.
It is well established, as demonstrated in several studies, that the delineation and mapping of debris-free glaciers using automatic and semi-automatic classification techniques on optical remote sensing data are feasible [13,47,48]. However, debris on rock glaciers and debris-covered glaciers are spectrally similar to their surroundings, making it difficult to distinguish these landforms using only spectral information [49]. This similarity limits the effectiveness of traditional approaches for the delineation and mapping of rock glaciers [26]. While previous studies have shown that the synergistic approach combining thermal and optical remote sensing data can be useful for mapping debris-covered glaciers [49,50], this approach is less effective for heavily debris-covered or rock glaciers [51]. Given these limitations, manual delineation remains the most feasible approach for accurately mapping rock glaciers [29,30,40,52,53,54]. Several studies have successfully employed manual delineation techniques, using publicly accessible high-resolution optical satellite imageries such as QuickBird, WorldView, and IKONOS, to compile rock glacier inventories in various regions, including parts of the Himalayas [26,40,54,55,56,57,58,59].
Notably, unlike existing inventories in the Jhelum basin [60,61], this study not only provides a comprehensive rock glacier inventory but also includes a detailed analysis of their water storage capacity. While Majeed et al. [60] inventoried 231 active rock glaciers, we expanded our inventory to include active, inactive, and relict rock glaciers, totaling 240, following the guidelines set by the International Permafrost Association (IPA) Action Group on Rock Glacier Inventory and Kinematics (RGIK). Similarly, Remya et al. [61] focused on 207 active and relict rock glaciers.
The novelty of this work lies in its comprehensive documentation and characterization of all types of rock glaciers, along with estimates of their water storage capacity in the Jhelum basin, Kashmir Himalaya. Furthermore, we conducted a detailed uncertainty assessment of the rock glacier inventory and employed statistical tests, including a correlation analysis and t-tests, to determine the relationship and significance of differences between rock glaciers and their morphological and topographical parameters. The work involves identifying these landforms, understanding their distribution in relation to lithology and topography, examining their development and dynamics, and recognizing their vital hydrological role as potential critical water sources in regions facing glacier recession due to climate change. These findings provide essential baseline data for future research on rock glacier dynamics and their contribution to evolving hydrological systems, as well as support of climate adaptation and sustainable water resource management initiatives in the Jhelum basin.

2. Study Area

The Jhelum basin, whose catchment boundaries coincide with the Kashmir valley, drains into the Jhelum River, a major tributary of the Indus River (Figure 1), covering an area of about 15,534 km2 [62]. The basin is flanked by the Pir Panjal mountain range to the southwest and the Greater Himalayan range to the northeast. About 0.46% of the basin area is glacier-covered, with most glaciers concentrated at altitudes between 4500 and 5000 m asl. While the majority of glaciers in the Jhelum basin are clean, a few have considerable supra-glacial debris cover in the ablation zone [63]. As of 2018, the Jhelum basin has 153 clean and debris-covered glaciers, covering ~72 km2 [38]. Kolahoi, the largest glacier in the basin [64], is located in the Lidder sub-basin and covers an area of ~11 km2. Most of these glaciers are concentrated in the Lidder and Sind sub-basins, covering ~45% of the glacier area in each of the two basins [38]. The climate of the study area is predominantly influenced by western disturbances [65], giving the basin a Mediterranean climate with four distinct seasons: winter (December to February), spring (March to May), summer (June to August), and autumn (September to November). The basin receives an average annual precipitation of ~1200 mm [66], mostly during winters, and primarily in the form of snow. Temperatures in the study area range from −10 to 35 °C [67].

3. Materials and Methods

3.1. Data Sources

The rock glacier inventory was manually created using Google Earth images and complimented by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Digital Elevation Model version 2 (GDEM 02). Google Earth not only allows the exploration of high-resolution satellite images, but also offers user-friendly GIS tools for creating geospatial databases [54,59]. In this study, 210 rock glaciers were mapped using CNES/AIRBUS and MAXAR TECHNOLOGIES optical images from 2017, with a spatial resolution of ~0.5 m, available on the Google Earth platform (Table 1). The platform’s historical imagery navigation tool was particularly useful in identifying rock glaciers, helping to resolve potential ambiguities caused by seasonal snow cover, clouds and shadows [59]. The 3D visualization feature of Google Earth also proved useful in the identification and delineation of rock glacier landforms.
Due to the lack of a high-resolution digital elevation model, we used the relatively coarser resolution ASTER GDEM in this study to compute the topographic parameters of rock glaciers, including elevation, slope, and aspect. The ASTER GDEM V2, with a horizontal resolution of 30 m and a vertical accuracy of 12.26 m [69,70], has been widely used in glaciological studies worldwide [71,72,73,74,75] and was deemed suitable for this study.

3.2. Identification and Mapping of Rock Glaciers

The rock glacier inventory was developed in accordance with the guidelines set by the International Permafrost Association (IPA) Action Group on Rock Glacier Inventories and Kinematics (RGIK) [4]. We divided the study area into 10 × 10 km grids and performed a visual analysis of Google Earth images within each grid to identify the presence of rock glaciers [29,30]. For this, we applied the “geomorphological approach” as outlined in the RGIK initiative [4], which focuses on distinct characteristics of rock glaciers. These include well-developed longitudinal and transversal ridges and furrows indicting signs of flow [76], swollen bodies suggesting the potential presence of ice [77], and steep frontal slopes [77]. The specific geomorphic indicators used as criteria for rock glacier identification and mapping are presented in Table 2.
Following the IPA guidelines [4], we first identified rock glacier landforms, then proceeded to locate each rock glacier and assigned it a unique identifier using latitude and longitude. Additionally, information about the activity of each rock glacier was added to the respective landform in the Google Earth environment. After identification, the rock glaciers were manually digitized as polygons, encompassing the entire rock glacier up to the rooting zone and including the front and lateral margins (extended geomorphological footprint), in accordance with IPA guidelines [4]. The rock glacier polygons, along with basic attributes such as latitude, longitude, ID, and area, were exported to ArcGIS 10.1 software (https://www.esri.in/en-in/products/arcgis-desktop/overview, accessed on 5 June 2024) for further analysis (Table 3).
In addition to these attributes, the rock glacier inventory included precise and detailed characteristics such as the minimum, maximum, and mean elevation slope, length (parallel to flow), width (perpendicular to flow), and aspect (main aspect of flow), calculated using the ASTER GDEM. The minimum elevation of each rock glacier was calculated at the lowest point where the front slope of the rock glacier met the underlying slope [53]. Similarly, the maximum elevation for each polygon was recorded at the head of the rock glacier. Elevation and slope data were extracted from the ASTER GDEM using the Zonal Statistics raster tool in ArcGIS 10.1 software [29]. Aspect was manually derived along the flow direction and classified into eight classes [59]. Length and width measurements were calculated using the ruler tool in the Google Earth platform [54]. To account for varying widths along the length of a rock glacier, several widths were digitized as lines at intervals of ~50 m perpendicular to the polygon length, and these were then exported to ArcGIS 10.1 software to calculate mean widths (Figure 2; [29]). Furthermore, we used the correlation coefficient [85] to determine the relationships between rock glacier parameters. A t-test was also conducted to assess the significance of the differences observed between various rock glacier parameters [86].

3.3. Classification of Rock Glaciers

Based on geomorphology, rock glacier landforms were categorized as either tongue-shaped or lobate-shaped. A length-to-width ratio greater than 1 indicates a tongue-shaped rock glacier, while a ratio less than 1 indicates a lobate-shaped rock glacier [87,88]. The length and width of a rock glacier are crucial factors in determining its form and contributing area. For instance, a rock glacier that is longer than it is wide is typically constrained by cirque or valley walls, whereas one that is wider than it is long suggests that it receives ice and debris from the sides or walls of the valley [89].
Furthermore, we classified rock glaciers based on their activity. The activity of each rock glacier was determined using geomorphological indicators specified in Barsch [3] and the RGIK initiative [4]. Consequently, rock glaciers in this study were classified into three types: active, inactive, and relict. In the absence of kinematic data, active rock glacier landforms are identified from satellite images as features with a steep frontal slope typically greater than the angle of repose. They exhibited prominent flow-like morphometric features, longitudinal or transverse ridge and furrow assemblages, and sharp-crested front and lateral slopes [4,56,78,79]. Inactive rock glaciers are characterized by geomorphological evidence such as more subdued micro-surface topography and gentler, dark-colored, rock-varnished frontal and lateral slopes (Figure 3; [80]). These landforms may be climatically inactive due to ice melting or dynamically inactive due to the reduced nourishment of talus and/or ice [90].
Relict rock glaciers, which do not show any geomorphological evidence of recent movement, are characterized by collapse structures on their surfaces due to the melting of ice content. They also exhibit subtle micro-reliefs and shallow- and round-crested frontal and lateral slopes (Figure 4; [4,53,79]). Typically, relict rock glaciers have concave longitudinal profiles [82]. Compared to active and inactive rock glaciers, relict rock glaciers may sometimes have vegetated surfaces and are usually situated at lower elevations [53,77]. However, it is noteworthy that the presence of vegetation on a rock glacier is not specifically associated with relict glaciers. Active and inactive rock glaciers are collectively referred to as ‘intact rock glaciers’ [78].

3.4. Rock Glacier Water Storage Assessment

Due to the lack of detailed subsurface data for rock glaciers globally and in the Himalayas, researchers have commonly used empirical thickness–area (H–S) relationships to estimate rock glacier thickness and volume [28,29,30,57,83,91,92,93,94]. The empirical H–S relation used in this study estimates the mean rock glacier thickness ( h ) as a function of the rock glacier surface area ( S ) in km2, using a scaling parameter c = 50 and a scaling exponent β = 0.2 , as described below [91]:
h = c S β
The rock glacier volumes are then determined as follows:
V = h . S
The water volume equivalent (WVEQ) of rock glaciers was then estimated by multiplying the calculated volume ( V ) by the estimated ice content (% by volume) [26], assuming an ice density of 900 kg m−3 [26,95]. While the values of c and β are expected to vary across regions [96], existing rock glacier studies typically apply a constant scaling parameter c and scaling exponent β when employing empirical power–law relations [28,29,57,91,92,93,94,97,98]. We followed this approach and assumed a standard volumetric rock glacier ice content of 50% [26,91]. Furthermore, our estimation of rock glacier WVEQ included both active and inactive rock glaciers.

3.5. Uncertainty Assessment

While the optical characteristics of rock glaciers are similar to those of debris-covered glaciers [40], mapping rock glaciers presents greater challenges. Visual image interpretation, being inherently subjective, can lead to significant variability in rock glacier outlines, as demonstrated by Brardinoni et al. [99], who observed considerable differences when different analysts mapped the same rock glaciers using high-resolution images. Paul et al. [48] found similar variability in the mapping of debris-covered glaciers. To reduce subjectivity and quantify the uncertainty associated with rock glacier area estimates, a set of 26 glaciers was selected for mapping by eight different analysts. The standard deviation of the area estimates was used to quantify the uncertainty for rock glacier area.
For the accuracy assessment, rock glaciers were randomly selected to ensure representation across all size categories: about 10% in the <0.10 km2 and 0.10–0.50 km2 size categories, and around 20% in the >0.5 km2 size category. Furthermore, this study estimated uncertainty in glacier elevation and slope measurements due to the uncertainties in glacier aerial extents. Figure 5 represents an example of a rock glacier mapped by eight different analysts. The uncertainty in rock glacier ice storage primarily arises from errors in the rock glacier inventory, limitations in the methodology, and inaccuracies in rock glacier thickness estimation. However, this study specifically quantified errors associated with the assumption regarding rock glacier ice content [29], using three values of volumetric rock glacier ice content: 40% (lower), 50% (mean), and 60% (upper), based on previous research [30,57,91,92,94].

4. Results

4.1. Rock Glacier Inventory

In this study, we identified and mapped 240 rock glaciers covering an area of 41.25 ± 2.2 km2. The individual rock glacier areas range from 0.003 to 1.03 km2, with an average area of 0.17 km2 (Supplementary Table S1). Rock glaciers are predominantly found in the Pir Panjal mountain range, with 194 glaciers constituting ~81% of the total in the basin. The Greater Himalayan range, located to the northeast of the study area, contains 46 rock glaciers, accounting for ~19% of the total rock glaciers in the basin. Only two of the rock glaciers exceeded 1 km2 in size.
The widths of the rock glaciers range from 55 m to 1330 m, with a mean value of 315 m. The maximum lengths range from 90 m to 2165 m, with a mean length of 654 m. The analysis revealed that 81% of the rock glaciers have a maximum length of less than 1 km, with only two glaciers exceeding 2 km in length. Smaller rock glaciers, with lengths <1 km, exhibited a higher mean altitude (4000 m asl) and minimum altitude at the fronts (MAFs, 3944 m asl) compared to larger rock glaciers over 1 km in length, which had a mean latitude of 3985 m asl and MAF of 3844 m asl. Among the inventoried rock glaciers, only four have widths exceeding 1 km, and 98% of the glaciers have a length less than 1 km, with a mean width of 315 m.
Among the 240 rock glaciers, 124 are smaller than 0.10 km2, and 99 fall within the size range of 0.10–0.50 km2. Only 17 rock glaciers are larger than 0.5 km2, including two that exceed 1 km2; these larger glaciers account for roughly 31.3% of the total rock glacier area in the basin. The rock glacier size category of <0.10 km2 covers the smallest area at 13.4%, while the 0.1–0.5 km2 category accounts for more than half of the total rock glacier area in the basin (55.2%). Rock glaciers with an area of <0.10 km2 are found at a relatively higher mean elevation of 4010 m asl, whereas those in the other two categories have similar mean elevations of 3989 m asl (0.1–0.5 km2) and 3987 m asl (>0.5 km2). Additionally, rock glaciers under 0.10 km2 in area have a slightly steeper mean slope of ~21° compared to a mean slope of ~18.5° in the other two size categories (Table 4).
Furthermore, rock glaciers in the Pir Panjal mountain range are more abundant and slightly larger in size (194 rock glaciers, average size of 0.18 km2) compared to those in the Greater Himalayan range (46 rock glaciers, average size of 0.13 km2). The results of the t-test indicate that the 27.7% difference in average rock glacier size between the two mountain ranges is statistically significant (p = 0.003).

4.2. Rock Glacier Classification

The majority of the rock glaciers (~97%) inventoried in this study are tongue-shaped, while the remaining 3% are lobate-shaped, as indicated by the length-to-width ratio analysis. Furthermore, 183 of the 240 inventoried rock glaciers were classified as active, accounting for 76.25% of the total in the basin, while 20% (count = 48) were classified as inactive. Only nine rock glaciers (3.75%) were classified as relict (Table 5). Active rock glaciers cover 35.55 km2, accounting for ~86% of the total rock glacier area in the basin. Inactive and relict rock glaciers constitute 7.5% and 6.2% of the total area, respectively. The investigation revealed that the inactive rock glaciers are relatively smaller in size (average of 0.06 km2) compared to active (0.19 km2) and relict (0.29 km2) rock glaciers. The difference in average size among these three types is statistically significant (p = 0.001, t-test). Furthermore, all relict rock glaciers were situated in the Pir Panjal mountain range, while all the rock glaciers in the Greater Himalayan range are inactive.

4.3. Rock Glacier Topography

The inventoried rock glaciers are located at altitudes ranging from ~3300 to ~4500 m asl, with mean minimum and maximum altitudes of 3925 and 4130 m asl, respectively. The majority of these rock glaciers (89.5%) are oriented toward the north, northeast, and northwest, while only 5% are found on southern slopes (S, SE, SW).
Rock glaciers in the study area are slightly more abundant (133) at elevations between 4000 and 4500 m asl (~55.5%) compared to those found at elevations between 3500 and 4000 m asl, where only 107 rock glaciers (~44.5%) were identified. The average size of rock glaciers is 0.19 km2 in the 3500–4000 m asl altitude range, compared to 0.15 km2 in the 4000–4500 m asl altitude range (Figure 6; Table 5). However, the total area covered by rock glaciers is roughly the same in both the elevation bands.
The mean slope of the rock glaciers in the basin ranges from 9° to 35°, with an average mean slope of 20°. Most of the rock glaciers (183), covering 83% of the total rock glacier area in the basin, have a mean slope between 15° and 25°. The number of rock glaciers with a mean slope in the range of 10–15° (30 rock glaciers) and 25–35° (27 rock glaciers) account for 13.7% and 3.3% of the total rock glacier area, respectively (Figure 7; Table 6). A negative correlation (r = −0.55) was observed between the mean slope and rock glacier area.
Rock glaciers in the study area were predominantly situated on northerly aspects, with 215 glaciers, accounting for 89.5% of the total number of rock glaciers, facing northwest, northeast, and north. Only 12 rock glaciers, accounting for 5% of the total, have southwest, southeast, and south aspects. The remaining three rock glaciers have east or west aspects. Additionally, the average size of rock glaciers on northerly aspects is 0.17 km2, which is smaller than the average size of rock glaciers in other aspect classes (Table 7, Figure 8). Rock glaciers with east-facing aspects have the largest mean area of 0.55 km2, followed by those on southern and western aspects, with average areas of 0.20 km2 and 0.19 km2, respectively. However, it is important to note that both rock glaciers greater than 1 km2 are north-facing.
Furthermore, it was found that the south-oriented rock glaciers are located at the highest elevations (average 4149 m asl), followed by east-facing rock glaciers, which are located at a mean altitude of 4062 m asl. In contrast, west- and north-facing rock glaciers are located at relatively lower mean elevations of 3937 m asl and 3995 m asl, respectively (Table 7). A significant difference (p = 0.005) in mean elevation was observed between north- and south-facing rock glaciers in this study. Similarly, there is a significant difference (p = 0.001) between south-facing glaciers and those oriented in other directions.
It was found that relict glaciers in the basin are generally situated at lower altitudes compared to the intact rock glaciers, with mean elevations of 3650 m asl and 4010 m asl, respectively. The lowest mean MAF was observed for relict rock glaciers situated at 3504 m asl, while the highest mean MAF was observed for inactive glaciers situated at 3775 m asl. The mean MAF for active rock glaciers, which are situated at altitudes ranging from 3316 to 4200 m asl, is 3575 m asl, which is higher than that of relict glaciers but lower than that of inactive glaciers.
Furthermore, the mean maximum elevation (3820 m asl) of the relict rock glaciers is significantly lower than that of active (4315 m asl) and inactive (4290 m asl) rock glaciers. This is further supported by the t-test, which showed a statistically significant difference (p = 0.001) of 364 m between the mean elevation of relict and intact glaciers in the basin. Additionally, relict rock glaciers were found to have a relatively flatter mean slope (~15.5°) compared to active and inactive rock glaciers in the basin, which have average slopes of 19.5° and ~21°, respectively (Table 5).

4.4. Rock Glacier Water Storage

The rock glaciers in the Jhelum basin have a water storage capacity of 0.80 ± 0.13 km3, equivalent to a water volume of 0.72 ± 0.12 km3, with an average ice thickness of 31 m, ranging from around 15 m to 50 m. Notably, glaciers in the elevation band of 3900–4200 m asl contain the largest WVEQ of 0.55 ± 0.08 km3, representing about 76.3% of the total rock glacier water storage in the basin. Likewise, about 84.7% of the total rock glacier water storage is concentrated within rock glaciers characterized by mean slopes ranging between 15° and 25°. The investigation also revealed that about 87.6% of the total rock glacier ice is stored in north-facing rock glaciers. Furthermore, the Pir Panjal mountain range, which contains the most abundant rock glaciers, stores about 0.62 ± 0.11 km3 of rock glacier water, accounting for 86% of the total rock glacier water storage in the basin.

4.5. Uncertainty Analysis

The uncertainty in the rock glacier area ranges from 0.001 to 0.2 km2, with an average uncertainty of 0.03 km2, resulting in an overall uncertainty of 19% in the calculation of the rock glacier area in the basin. Variations in delineating glacier outlines between eight analysts were more pronounced toward the upper boundary of the rock glacier landforms (Figure 5). Additionally, high-resolution Google Earth imagery was very effective in differentiating rock glacier landforms from other similar landforms, like heavily debris-covered glaciers, debris flows, and gelifluction, thereby helping in reducing the mapping uncertainty [59].
There is an average uncertainty of 171 m (in the range of 145 to 185 m) and 296 m (in the range of 263–323 m) in the mean MAF and mean maximum elevation, respectively. On average, an uncertainty of 208 m (in the range of 142–225 m) was found in the mean rock glacier elevation. The mapping error is estimated to result in an average uncertainty of 39 m (in the range of 7–165 m) in glacier length and 30 m (in the range of 5–129 m) in glacier width. Similarly, the maximum and mean slope are expected to have uncertainties of 3.2° (in the range of 2° to 5°) and 2.6° (in the range of 1–5°), respectively. However, the general aspect remained consistently the same when the glacier extents were mapped by different analysts. All analysts agreed on the existence of both intact and relict rock glaciers, although there was a disagreement between two of the analysts regarding whether two rock glaciers were active or inactive. Furthermore, we estimated an overall uncertainty of 16.3% in the rock glacier ice and water storage estimates presented in this study.

5. Discussion

5.1. Rock Glacier Inventory and Topographic Distribution

We identified and mapped 240 rock glaciers in this study, including 183 active, 48 inactive, and 9 relict rock glaciers. Due to intrinsic data constraints, such as seasonal snow, cloud cover, and shadowing in the remote sensing data, particularly in the complex Himalayan terrain, the omission of a few more rock glaciers due to human error cannot be ruled out [59]. The rock glaciers investigated in this study are mostly clustered. The average area (0.17 km2), length (654 m), and width (315 m) of the rock glaciers observed in this study are lower than the average area (0.68 km2), length (1600 m), and width (375 m) of rock glaciers reported in the neighboring Himachal Himalaya, India [59]. The higher mean MAF (4484 m asl) of the rock glaciers in Himachal Pradesh, India, explains the presence of relatively larger rock glaciers in that region. Rock glaciers are more prevalent and generally larger in the Pir Panjal range than they are in the Greater Himalayan range of the Jhelum basin. The t-test analysis showed that the 27.7% difference in average rock glacier size between the two mountain ranges is statistically significant (p = 0.003).
The lowest MAF of 3316 m asl observed in this study is consistent with the MAF reported for the western Himalaya (3052 m asl, [59]), Nepalese Himalaya (3225 m asl, [57], Karakoram Hindu Kush region (3500 m asl, [40]), and Tien Shan region (3174 m asl, [100]). The MAF observed in the present study is in good agreement with the lower limit (~3272 m asl) of the permafrost model by Gruber [101] and Gruber et al. [102]. It is worth noting that the MAF for rock glaciers is often considered a good approximation of the lower limit of discontinuous permafrost [53]. This study reveals that no active rock glaciers are situated below 3316 m asl, indicating that this may be the lower limit of permafrost in the Jhelum basin. This is ~884 m lower than the lower limit of permafrost (~4200 m asl) in the Kulu district, Himalcah Pradesh [45] and ~572 m and 684 m lower than the lower limit of permafrost in the Lahul Himalaya (3888 m asl) and the Garhwal Himalaya (4000 m asl), respectively. Similarly, the estimated permafrost lower limit for the Jhelum basin is considerably lower than the permafrost lower limit of 4727 m asl reported by Wani et al. [103] in the Ladakh region. It is also noteworthy that the MAF observed in the present study is slightly higher than the MAF of 3019 m asl reported by Majeed et al. [60] but lower than the MAF of 3791 m asl reported by Remya et al. [61] in the Jhelum basin. Pandey [59] also reported the occurrence of a rock glacier at a lower elevation of 3052 m asl in the neighboring Chenab basin, western Himalaya, which is lower than the minimum elevation of rock glaciers reported in the current study. However, since Pandey [59] identified only a single rock glacier landform, misinterpretation in mapping cannot be ruled out. The presence of a rock glacier below the lower limit of permafrost is due to their slow dynamical downslope motion [45].
We also conducted a comparative analysis of the findings from this study with rock glacier inventories reported from different regions worldwide. However, the analysis is limited to studies that provided data on the number, area, and at least one of the three elevation parameters (i.e., minimum, maximum, or mean) (Table 8). From this analysis, we found that the mean minimum elevation of rock glacier landforms in the Jhelum basin is lower than that reported in several other Himalayan regions and higher than that reported in several other mountainous regions globally. As expected, intact rock glaciers are located at higher altitudes compared to relict glaciers worldwide (Table 8). Furthermore, across the Himalayan region, we observed a westward decreasing trend in rock glacier elevation (Table 8). The trend remains consistent when active, inactive, and relict rock glaciers are considered separately. The variations in rock glacier numbers and area in the present study compared to recent inventories by Majeed et al. [60] and Remya et al. [61] can be explained by the fact that this study identified and mapped all three types of rock glacier landforms, unlike the previous studies.
Moreover, the distribution of rock glaciers is climatically controlled by precipitation and temperature, which are considerably influenced by elevation [54]. This explains why the elevation band of 4000–4500 m asl contains more rock glacier landforms than the 3500–4000 m asl elevation band.
The study area exhibits a precipitation gradient of 0.13% m−1 [113] and a mean temperature lapse rate of 7.5 °C km−1 at altitudes above 3100 m asl [62]. The shallow slopes (15–25°) provide a suitable niche for debris accumulation, favoring the development of rock glacier landforms [114]. We found a negative correlation (r = −0.55) between rock glacier coverage and slope. The topographic analysis of our rock glacier inventory showed that 90% of the rock glaciers are north-facing. Due to reduced solar insolation and the correspondingly greater accumulation of snow, ice, and rock debris, north-facing slopes in the Northern Hemisphere are more likely to harbor clean, debris-covered, and rock glaciers [29]. The prevalence of rock glacier landforms on northern slopes found in this study are consistent with other findings in the Hindu Kush Himalaya region [59,100]. This inventory also reveals that, due to reduced insolation, rock glaciers can exist at lower altitudes on northern slopes compared to southern slopes, corroborating previous findings in the Himalayas [53,110]. We observed a statistically significant difference of 155 m (p = 0.001) in the mean altitude between north- and south-facing rock glacier landforms.
Expectedly, relict rock glaciers are situated at lower elevations than intact rock glaciers [77]. The relatively higher temperatures at lower altitudes accelerate ice melting [13,114], increasing the likelihood of relict rock glacier formation. The MAF, or the elevation at the front of an active rock glacier, is often related to the 0°C isotherm [54], which in this study is estimated to be between ~3300 and 4200 m asl. The relict rock glacier landforms (Figure 4), inferred as former rock glaciers, represent a shift in the 0 °C isotherm over time due to climate change and/or debris supply [93].
Notably, the MAF of relict and active rock glaciers showed a mean difference of 113 m, which is thought to represent the upward shift in the isotherm over time [54]. Additionally, future climate change projections for the study area indicate a significant rise in temperatures [113], which may shrink the suitable niches for the formation and persistence of active rock glaciers as the 0 °C isotherm moves closer to or above the maximum altitude of the mountains [54]. As a result of the warming climate, which is expected to be more pronounced at higher altitudes in mountainous regions [115,116], it is predicted that the number of active rock glaciers will continue to decrease while the number of relict rock glaciers will correspondingly increase [111] in the study area.
Furthermore, this study revealed that the Pir Panjal mountain range has a higher abundance of rock glaciers in terms of numbers, coverage, and water storage compared to the Greater Himalayan range. The average rock glacier area of 0.2 km2 and 0.1 km2 in Pir Panjal and the Greater Himalayan range, respectively, is statistically significant (p = 0.003). Similarly, we observed a statistically significant difference of 91 m (p = 0.0001) in the mean elevation of rock glaciers between these mountain ranges. Glacial history, debris supply, and climate conditions, particularly precipitation and temperature, the latter being significantly influenced by elevation and aspect, play a substantial role in rock glacier development, characterization and distribution [87,117,118]. However, despite more favorable climatic and topographic conditions, such as higher elevation and lower surface temperatures [13,119], the distribution of rock glacier landforms remains limited in the Greater Himalayan mountain range, warranting further discussion and investigation. This suggests that other factors such as rock supply, lithology, and glacial history also impact the formation and persistence of rock glaciers at higher elevations [91,117]. Additionally, the lithology of the two mountain ranges at higher elevations is broadly similar and dominated by volcanic rocks (Panjal volcanics), which are less susceptible to weathering and erosion (Figure 9). The Pir Panjal range, however, is tectonically more active than the Greater Himalayas, uplifting at the rate of 10 mm a−1 [120]. This tectonic activity makes it more susceptible to weathering and debris formation due to the deformation of rocks under compressional stresses, leading to the development of various glacier erosional landforms in the mountain range [121]. Determining the lithological and tectonic control on the rock glacier formation, however, requires more detailed investigation.
Glacier recession and shrinkage are considered to be of great significance for the evolution and origin of rock glaciers, as the transition from alpine glaciers to cirque glaciers often results in rock glacier formation [122,123]. Although the entire study area has been experiencing glacier recession, this phenomenon is more pronounced in the Pir Panjal mountain range [38]. The evidence of former glaciation in the Pir Panjal mountain range is quite apparent in the form of typical glacio-geomorphological landforms [124]. The abundance of rock glaciers in the Pir Panjal range could, therefore, be partly linked to its glacier recession history. In contrast to the 26.2% glacier recession observed in the Greater Himalayan range of the Jhelum basin, the Pir Panjal range has seen a glacier recession of 51.6% between 1980 and 2018 [38].
Figure 9. Lithology of the Jhelum basin encompassing the Kashmir valley, modified after Thakur and Rawat [125].
Figure 9. Lithology of the Jhelum basin encompassing the Kashmir valley, modified after Thakur and Rawat [125].
Water 16 02327 g009

5.2. Water Storage Estimation

In light of the accelerated glacier recession observed in the study area, the rock glacier water storage (0.72 ± 0.12 km3 WVEQ) will serve as an important water resource at short-, medium-, and long-term timescales. Recent research underscores the importance of rock glaciers as significant long-term water reservoirs, especially in deglaciating and deglaciated semi-arid and arid regions [30]. Consequently, the initial estimates of rock glacier water storage in the Jhelum basin provided in this study are crucial for conducting a more comprehensive assessment of water storage at various timescales. This will enhance our understanding of the dynamics and future implications of these water resources in the context of climate change. The assessment of water resources from rock glaciers will facilitate better management and planning of these depleting resources in the basin, which is currently lacking. Notably, the 157 clean and debris-covered glaciers cover ~72 km2 [68] and rock glaciers span 41.2 km2 in the Jhelum basin. This highlights their significant role in meeting the increasing water demands for agriculture, horticulture, and domestic use in the basin.
Furthermore, understanding the seasonal variations in rock glacier water flow is crucial for assessing their impact on both ecosystems and human communities [126]. Rock glaciers typically release more water compared to clean and debris-covered glaciers, as the melting process is slower and occurs over extended periods. This delayed response helps buffer the hydrological impacts of seasonal fluctuations, providing a sustained water supply during dry seasons or droughts [127]. Consequently, rock glaciers can play a significant role in ensuring the availability of water resources during peak agricultural demands or dry spells [20,128].
The seasonal meltwater from rock glaciers is also crucial for maintaining ecological balance. Many ecosystems rely on perennial water flows to sustain various plant and animal species [126]. In the Jhelum basin, where seasonal water variability is pronounced during dry periods, the steady meltwater from rock glaciers helps stabilize streamflows, supporting aquatic habitats and riparian vegetation. This buffering effect is important for maintaining biodiversity and ensuring the health of ecosystems that might otherwise be vulnerable to the impacts of a fluctuating water supply [129].

5.3. Impacts of Climate Change on Rock Glaciers

It is pertinent to mention that the temperature in the Jhelum basin is projected to increase by 3 °C and 5.2 °C under the RCP4.5 and RCP8.5 climate change scenarios, respectively, by the late twenty-first century[130]. While precipitation is expected to see a marginal increase by the end of the century, the region is already experiencing significant changes in its form [121,124]. This rise in temperature and shift in precipitation is anticipated to cause substantial long-term changes in the melting and dynamics of rock glaciers, despite their delayed response to climate fluctuations.
In fact, some of the recent studies suggest increased rock glacier surface velocities in response to the warming climate [57]. However, investigations aimed at the assessment of the impact of future climate change on rock glaciers are still in their infancy [26]. Improved modeling efforts focused on understanding changes in the thermal regimes of rock glaciers under various climate change scenarios are necessary. This will enhance our knowledge of rock glacier dynamics and their future evolution, which is crucial for assessing their long-term hydrological impacts.
The rock glaciers’ consistent water supply is invaluable for the Jhelum basin, being crucial for agriculture, horticulture, and domestic use. As ice glaciers recede faster, rock glaciers become increasingly important in meeting water demands. Climate change projections in the Jhelum basin indicate an earlier melt of snow and ice glaciers, shifting streamflow peak to early spring [128,130]. Rock glaciers, with their delayed response to climate change, will ensure stable and perennial water resources. Effective management and planning of these resources are essential to meet the water needs of the basin’s communities and mitigate the effects of diminishing clean and debris-covered glaciers.
Additionally, the investigation revealed that some of the rock glaciers have slid down the valley slopes, even reaching up to roadways and streams, thus threatening lives and infrastructure in the study area (Figure 10). Such rock glaciers have the potential to dam the stream, which upon breach can result in flash floods with catastrophic consequences downstream, particularly under the projected climate change conditions. It is important to note that people are constantly visiting these rock glacier areas for various purposes. The protruding rock glaciers can further slide and obstruct the roadways restricting the movement of tourists, shepherds, and security personnel deployed in these areas. These roadways are used as supply lines by shepherds, cattle herders, and the military, as well as a large number of tourists who trek on these roads round the year.

5.4. Uncertainty

This study provides a comprehensive assessment of the uncertainty in the rock glacier inventory of the Jhelum basin, revealing a 19% uncertainty in the rock glacier area. Analysts showed greater disagreement in delineating the upper parts of rock glacier landforms, with less uncertainty in the termini positions, consistent with previous studies [99]. Since delineating the upper boundary of rock glaciers is challenging [111], this boundary was demarcated based on considered judgement [54,59]. However, the uncertainties associated with delineating upper boundaries are more consistent in this study because the inventory was compiled by a single analyst. Furthermore, the demarcation and mapping of complex rock glaciers, where multiple glaciers merge, followed the methodologies of Scotti et al. [53] and Jones et al. [57], despite their subjectivity [40,53]. The uncertainty in the minimum, maximum, and mean elevations is slightly higher than reported by Brardinoni et al. [99] but comparable to the uncertainty reported by Jones et al. [29]. Additionally, the uncertainty in rock glacier area assessed in this study aligns with the error estimates of Brardinoni et al. [99]. The 16.3% uncertainty for rock glacier ice and water storage is also consistent with previous studies [29,30,57].

6. Conclusions

In this study, we developed a comprehensive inventory of rock glaciers in the Jhelum basin, Kashmir Himalaya, supported with a detailed uncertainty and accuracy assessment of all rock glacier parameters. In comparison to 153 clean ice glaciers occupying ~72 km2, this study identified 240 rock glacier landforms in the Jhelum basin, covering 41.24 ± 2.2 km2, of which 231 are intact rock glaciers (active and inactive) and the remainder are relict rock glaciers. The majority of these glaciers are located in the Pir Panjal mountain range. Despite favorable climatic and topographic conditions, the limited number of rock glaciers in the Greater Himalayan mountain range suggests an influence of lithology, debris supply, tectonics, and past glaciation on their formation. Additionally, the occurrence of the majority of rock glaciers (90%) on north, northeast, and northwest slopes highlights the role of reduced insolation in their formation and persistence. The absence of active rock glaciers below 3316 m asl suggests that this elevation may be considered as the lowest limit of permafrost in the Jhelum basin, which is lower than the limits reported in several other Himalayan regions.
This study also estimated rock glacier ice storage at 0.80 ± 0.13 km3, equivalent to a water volume of 0.72 ± 0.12 km3, with a predominant contribution from the rock glaciers in the Pir Panjal range. Therefore, this study stands out from previous studies on the subject by incorporating a detailed analysis of the water storage capacity of these landforms in the basin. Due to the limited number of clean ice glaciers, accelerated glacier recession in the Pir Panjal range, and the projected climate warming across the entire study area, the rock glaciers identified in this study are crucial for meeting the region’s water source demands for agriculture, horticulture, industry, domestic use and other uses. The rock glacier inventory and ice storage estimates provide essential baseline data for future research on rock glacier development, dynamics, and their role and importance in the local and regional hydrological regimes of the Kashmir Himalayan region, which is under stress from climate changes.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/w16162327/s1. Table S1: Details of all the rock glaciers mapped in this study.

Author Contributions

Conceptualization, S.A.R. and T.A.; methodology, S.A.R. and T.A.; software, T.A.; validation, T.A. and S.A.R.; formal analysis, T.A. and S.A.R.; investigation, T.A. and S.A.R.; resources, S.A.R.; data curation, T.A.; writing, S.A.R. and T.A.; visualization, T.A.; supervision, S.A.R.; project administration, S.A.R.; funding acquisition, S.A.R. All authors have read and agreed to the published version of the manuscript.

Funding

The research was supported by Department of Science and Technology (DST), Government of India, under grant number DST/CCP/CoE/183/2019(G).

Data Availability Statement

The Rock Glacier Inventory and other data pertaining to the manuscript are provided in the Supplementary Material.

Acknowledgments

The research work was conducted as part of the research grant received from the Department of Science and Technology (DST), Government of India, under the research project titled “Centre of Excellence for Glacial Studies in Western Himalaya”. The financial assistance received from the Department under the project to accomplish the research is thankfully acknowledged.

Conflicts of Interest

The authors declared no potential conflicts of interest concerning the research, authorship, and publication of this article.

References

  1. Dutta, S.; Ramanathan, A.L.; Linda, A.; Pottakkal, J.G.; Singh, V.B.; Angchuk, T. Glacier Mass Balance and Its Significance on the Water Resource Management in the Western Himalayas. In Management of Water, Energy and Bio-Resources in the Era of Climate Change: Emerging Issues and Challenges; Springer: Cham, Switzerland, 2015; pp. 73–83. [Google Scholar]
  2. Kaser, G.; Großhauser, M.; Marzeion, B. Contribution Potential of Glaciers to Water Availability in Different Climate Regimes. Proc. Natl. Acad. Sci. USA 2010, 107, 20223–20227. [Google Scholar] [CrossRef]
  3. Immerzeel, W.W.; van Beek, L.P.H.; Bierkens, M.F.P. Climate Change Will Affect the Asian Water Towers. Science 2010, 328, 1382–1385. [Google Scholar] [CrossRef]
  4. RGIK. Towards Standard Guidelines for Inventorying Rock Glaciers: Baseline Concepts, Version 4.2.2 13; IPA Action Group Rock Glacier Inventories and Kinematics: Attica, Greece, 2022. [Google Scholar]
  5. Nüsser, M.; Schmidt, S. Glacier Changes on the Nanga Parbat 1856–2020: A Multi-Source Retrospective Analysis. Sci. Total Environ. 2021, 785, 147321. [Google Scholar] [CrossRef] [PubMed]
  6. Brombierstäudl, D.; Schmidt, S.; Nüsser, M. Spatial and Temporal Dynamics of Aufeis in the Tso Moriri Basin, Eastern Ladakh, India. Permafr. Periglac. Process. 2023, 34, 81–93. [Google Scholar] [CrossRef]
  7. Bolch, T.; Shea, J.M.; Liu, S.; Azam, F.M.; Gao, Y.; Gruber, S.; Immerzeel, W.W.; Kulkarni, A.; Li, H.; Tahir, A.A.; et al. Status and change of the cryosphere in the extended Hindu Kush Himalaya region. In The Hindu Kush Himalaya Assessment; Springer: Cham, Switzerland, 2019. [Google Scholar]
  8. Gardner, A.S.; Moholdt, G.; Cogley, J.G.; Wouters, B.; Arendt, A.A.; Wahr, J.; Berthier, E.; Hock, R.; Pfeffer, W.T.; Kaser, G.; et al. A Reconciled Estimate of Glacier Contributions to Sea Level Rise: 2003 to 2009. Science 2013, 340, 852–857. [Google Scholar] [CrossRef] [PubMed]
  9. Marzeion, B.; Jarosch, A.H.; Hofer, M. Past and Future Sea-Level Change from the Surface Mass Balance of Glaciers. Cryosphere 2012, 6, 1295–1322. [Google Scholar] [CrossRef]
  10. Lyu, Y.; Chen, H.; Cheng, Z.; He, Y.; Zheng, X. Identifying the Impacts of Land Use Landscape Pattern and Climate Changes on Streamflow from Past to Future. J. Environ. Manag. 2023, 345, 118910. [Google Scholar] [CrossRef] [PubMed]
  11. Bhambri, R.; Schmidt, S.; Chand, P.; Nüsser, M.; Haritashya, U.; Sain, K.; Tiwari, S.K.; Yadav, J.S. Heterogeneity in Glacier Thinning and Slowdown of Ice Movement in the Garhwal Himalaya, India. Sci. Total Environ. 2023, 875, 162625. [Google Scholar] [CrossRef]
  12. Rashid, I.; Abdullah, T.; Romshoo, S.A. Explaining the Natural and Anthropogenic Factors Driving Glacier Recession in Kashmir Himalaya, India. Environ. Sci. Pollut. Res. 2022, 30, 29942–29960. [Google Scholar] [CrossRef]
  13. Romshoo, S.A.; Abdullah, T.; Rashid, I.; Bahuguna, I.M. Explaining the Differential Response of Glaciers across Different Mountain Ranges in the North-Western Himalaya, India. Cold Reg. Sci. Technol. 2022, 196, 103515. [Google Scholar] [CrossRef]
  14. Kamp, U.; Bolch, T.; Olsenholler, J. Geomorphometry of Cerro Sillajhuay (Andes, Chile/Bolivia): Comparison of Digital Elevation Models (DEMs) from ASTER Remote Sensing Data and Contour Maps. Geocarto Int. 2005, 20, 23–33. [Google Scholar] [CrossRef]
  15. Schmidt, S.; Nüsser, M. Changes of High Altitude Glaciers in the Trans-Himalaya of Ladakh over the Past Five Decades (1969–2016). Geosciences 2017, 7, 27. [Google Scholar] [CrossRef]
  16. Schmidt, S.; Nüsser, M. Changes of High Altitude Glaciers from 1969 to 2010 in the Trans-Himalayan Kang Yatze Massif, Ladakh, Northwest India. Arctic Antarct. Alp. Res. 2012, 44, 107–121. [Google Scholar] [CrossRef]
  17. Radić, V.; Bliss, A.; Beedlow, A.C.; Hock, R.; Miles, E.; Cogley, J.G. Regional and Global Projections of Twenty-First Century Glacier Mass Changes in Response to Climate Scenarios from Global Climate Models. Clim. Dyn. 2014, 42, 37–58. [Google Scholar] [CrossRef]
  18. Huss, M.; Hock, R. A New Model for Global Glacier Change and Sea-Level Rise. Front. Earth Sci. 2015, 3. [Google Scholar] [CrossRef]
  19. Rasul, G. Food, Water, and Energy Security in South Asia: A Nexus Perspective from the Hindu Kush Himalayan Region☆. Environ. Sci. Policy 2014, 39, 35–48. [Google Scholar] [CrossRef]
  20. Romshoo, S.A.; Dar, R.A.; Rashid, I.; Marazi, A.; Ali, N.; Zaz, S.N. Implications of Shrinking Cryosphere Under Changing Climate on the Streamflows in the Lidder Catchment in the Upper Indus Basin, India. Arctic Antarct. Alp. Res. 2015, 47, 627–644. [Google Scholar] [CrossRef]
  21. Shannon, S.; Smith, R.; Wiltshire, A.; Payne, T.; Huss, M.; Betts, R.; Caesar, J.; Koutroulis, A.; Jones, D.; Harrison, S. Global Glacier Volume Projections under High-End Climate Change Scenarios. Cryosphere 2019, 13, 325–350. [Google Scholar] [CrossRef]
  22. IPCC. Climate Change 2022: Impacts, Adaptation, and Vulnerability; Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change Cambridge University Press; Cambridge University Press: Cambridge, UK; New York, NY, USA, 2022.
  23. Kraaijenbrink, P.D.; Bierkens, M.F.; Lutz, A.F.; Immerzeel, W.W. Impact of a Global Temperature Rise of 1.5 Degrees Celsius on Asia’s Glaciers. Nature 2017, 549, 257–260. [Google Scholar] [CrossRef]
  24. Romshoo, S.A.; Marazi, A. Impact of Climate Change on Snow Precipitation and Streamflow in the Upper Indus Basin Ending Twenty-First Century. Clim. Chang. 2022, 170, 6. [Google Scholar] [CrossRef]
  25. Huss, M.; Hock, R. Global-Scale Hydrological Response to Future Glacier Mass Loss. Nat. Clim. Change 2018, 8, 135–140. [Google Scholar] [CrossRef]
  26. Jones, D.B.; Harrison, S.; Anderson, K.; Whalley, W.B. Rock Glaciers and Mountain Hydrology: A Review. Earth-Sci. Rev. 2019, 193, 66–90. [Google Scholar] [CrossRef]
  27. Zhang, Q.; Jia, N.; Xu, H.; Yi, C.; Wang, N.; Zhang, L. Rock Glaciers in the Gangdise Mountains, Southern Tibetan Plateau: Morphology and Controlling Factors. CATENA 2022, 218, 106561. [Google Scholar] [CrossRef]
  28. Azócar, G.F.; Brenning, A. Hydrological and Geomorphological Significance of Rock Glaciers in the Dry Andes, Chile (27–33 S). Permafr. Periglac. Process. 2010, 21, 42–53. [Google Scholar] [CrossRef]
  29. Jones, D.B.; Harrison, S.; Anderson, K.; Betts, R.A. Mountain Rock Glaciers Contain Globally Significant Water Stores. Sci. Rep. 2018, 8, 2834, Erratum in Sci. Rep. 2021, 11, 20997. [Google Scholar] [CrossRef]
  30. Jones, D.B.; Harrison, S.; Anderson, K.; Shannon, S.; Betts, R.A. Rock Glaciers Represent Hidden Water Stores in the Himalaya. Sci. Total Environ. 2021, 793, 145368. [Google Scholar] [CrossRef] [PubMed]
  31. Haeberli, W.; Hallet, B.; Arenson, L.; Elconin, R.; Humlum, O.; Kääb, A.; Kaufmann, V.; Ladanyi, B.; Matsuoka, N.; Springman, S.; et al. Permafrost Creep and Rock Glacier Dynamics. Permafr. Periglac. Process. 2006, 7, 189–214. [Google Scholar] [CrossRef]
  32. Harrison, S.; Jones, D.; Anderson, K.; Shannon, S.; Betts, R.A. Is Ice in the Himalayas More Resilient to Climate Change than We Thought? Geogr. Ann. Ser. A Phys. Geogr. 2021, 103, 1–7. [Google Scholar] [CrossRef]
  33. Schrott, L. Some geomorphological-hydrological aspects of rock glaciers in the Andes (San Juan, Argentina). Z. Geomorphol. 1996, 104, 161–173. [Google Scholar]
  34. Millar, C.I.; Westfall, R.D. Rock Glaciers and Related Periglacial Landforms in the Sierra Nevada, CA, USA; Inventory, Distribution and Climatic Relationships. Quat. Int. 2008, 188, 90–104. [Google Scholar] [CrossRef]
  35. Shen, Y.J.; Shen, Y.; Guo, Y.; Zhang, Y.; Pei, H.; Brenning, A. Review of Historical and Projected Future Climatic and Hydrological Changes in Mountainous Semiarid Xinjiang. CATENA 2019, 187, 104343. [Google Scholar] [CrossRef]
  36. Jansson, P.; Hock, R.; Schneider, T. The Concept of Glacier Storage: A Review. J. Hydrol. 2003, 282, 116–129. [Google Scholar] [CrossRef]
  37. Irvine-Fynn, T.D.; Hodson, A.J.; Moorman, B.J.; Vatne, G.; Hubbard, A.L. Polythermal Glacier Hydrology: A Review. Rev. Geophys. 2011, 49. [Google Scholar] [CrossRef]
  38. Romshoo, S.A.; Fayaz, M.; Meraj, G.; Bahuguna, I.M. Satellite-Observed Glacier Recession in the Kashmir Himalaya, India, from 1980 to 2018. Environ. Monit. Assess. 2020, 192, 597. [Google Scholar] [CrossRef] [PubMed]
  39. Brombierstäudl, D.; Schmidt, S.; Nüsser, M. Distribution and Relevance of Aufeis (Icing) in the Upper Indus Basin. Sci. Total Environ. 2021, 780, 146604. [Google Scholar] [CrossRef] [PubMed]
  40. Schmid, M.O.; Baral, P.; Gruber, S.; Shahi, S.; Shrestha, T.; Stumm, D.; Wester, P. Assessment of Permafrost Distribution Maps in the Hindu Kush Himalayan Region Using Rock Glaciers Mapped in Google Earth. Cryosphere 2015, 9, 2089–2099. [Google Scholar] [CrossRef]
  41. Bolch, T.; Gorbunov, A.P. Characteristics and Origin of Rock Glaciers in Northern Tien Shan (Kazakhstan/Kyrgyzstan). Permafr. Periglac. Process. 2014, 25, 320–332. [Google Scholar] [CrossRef]
  42. Hewitt, K. Glaciers of the Karakoram Himalaya. In Encyclopedia of Snow, Ice and Glaciers; Springer: Dordrecht, The Netherlands, 2014; pp. 429–436. [Google Scholar]
  43. Owen, L.A.; England, J. Observations on Rock Glaciers in the Himalayas and Karakoram Mountains of Northern Pakistan and India. Geomorphology 1998, 26, 199–213. [Google Scholar] [CrossRef]
  44. Shroder, J.F.; Bishop, M.P.; Copland, L.; Sloan, V.F. Debris-covered Glaciers and Rock Glaciers in the Nanga Parbat Himalaya, Pakistan. Geogr. Ann. Ser. A Phys. Geogr. 2000, 82, 17–31. [Google Scholar] [CrossRef]
  45. Allen, S.K.; Fiddes, J.; Linsbauer, A.; Randhawa, S.S.; Saklani, B.; Salzmann, N. Permafrost Studies in Kullu District, Himachal Pradesh. Curr. Sci. 2016, 111, 550–553. [Google Scholar] [CrossRef]
  46. Regmi, D. Rock Glacier Distribution and the Lower Limit of Discontinuous Mountain Permafrost in the Nepal Himalaya. In Proceedings of the Ninth International Conference on Permafrost (NICOP), Fairbanks, Alaska, 29 June–3 July 2008; Volume 29, pp. 1475–1480. [Google Scholar]
  47. Bolch, T.; Yao, T.; Kang, S.; Buchroithner, M.F.; Scherer, D.; Maussion, F.; Huintjes, E.; Schneider, C. A Glacier Inventory for the Western Nyainqentanglha Range and the Nam Co Basin, Tibet, and Glacier Changes 1976–2009. Cryosphere 2010, 4, 419–433. [Google Scholar] [CrossRef]
  48. Paul, F.; Barrand, N.E.; Baumann, S.; Berthier, E.; Bolch, T.; Casey, K.; Frey, H.; Joshi, S.P.; Konovalov, V.; Le Bris, R.; et al. On the Accuracy of Glacier Outlines Derived from Remote-Sensing Data. Ann. Glaciol. 2013, 54, 171–182. [Google Scholar] [CrossRef]
  49. Shukla, A.; Arora, M.K.; Gupta, R.P. Synergistic Approach for Mapping Debris-Covered Glaciers Using Optical–Thermal Remote Sensing Data with Inputs from Geomorphometric Parameters. Remote Sens. Environ. 2010, 114, 1378–1387. [Google Scholar] [CrossRef]
  50. Paul, F.; Winsvold, S.H.; Kääb, A.; Nagler, T.; Schwaizer, G. Glacier Remote Sensing Using Sentinel-2. Part II: Mapping Glacier Extents and Surface Facies, and Comparison to Landsat 8. Remote Sens. 2016, 8, 575. [Google Scholar] [CrossRef]
  51. Brenning, A. Benchmarking Classifiers to Optimally Integrate Terrain Analysis and Multispectral Remote Sensing in Automatic Rock Glacier Detection. Remote Sens. Environ. 2008, 113, 239–247. [Google Scholar] [CrossRef]
  52. Casassa, G.; Smith, K.; Rivera, A.; Araos, J.; Schnirch, M.; Schneider, C. Inventory of Glaciers in Isla Riesco, Patagonia, Chile, Based on Aerial Photography and Satellite Imagery. Ann. Glaciol. 2002, 34, 373–378. [Google Scholar] [CrossRef]
  53. Scotti, R.; Brardinoni, F.; Alberti, S.; Frattini, P.; Crosta, G.B. A Regional Inventory of Rock Glaciers and Protalus Ramparts in the Central Italian Alps. Geomorphology 2013, 186, 136–149. [Google Scholar] [CrossRef]
  54. Rangecroft, S.; Harrison, S.; Anderson, K.; Magrath, J.; Castel, A.P.; Pacheco, P. A First Rock Glacier Inventory for the Bolivian Andes. Permafr. Periglac. Process. 2014, 25, 333–343. [Google Scholar] [CrossRef]
  55. Stumm, D.; Schmid, M.; Gruber, S.; Baral, P.; Shahi, S.; Shrestha, T.; Wester, P. Manual for Mapping Rock Glaciers in Google Earth; International Centre for Integrated Mountain Development ICIMOD: Kathmandu, Nepal, 2015. [Google Scholar]
  56. Charbonneau, A.A.; Smith, D.J. An Inventory of Rock Glaciers in the Central British Columbia Coast Mountains, Canada, from High Resolution Google Earth Imagery. Arctic Antarct. Alp. Res. 2018, 50, 1489026. [Google Scholar] [CrossRef]
  57. Jones, D.B.; Harrison, S.; Anderson, K.; Selley, H.L.; Wood, J.L.; Betts, R.A. The Distribution and Hydrological Significance of Rock Glaciers in the Nepalese Himalaya. Glob. Planet. Change 2018, 160, 123–142. [Google Scholar] [CrossRef]
  58. Ran, Z.; Liu, G. Rock Glaciers in Daxue Shan, South-Eastern Tibetan Plateau: An Inventory, Their Distribution, and Their Environmental Controls. Cryosphere 2018, 12, 2327–2340. [Google Scholar] [CrossRef]
  59. Pandey, P. Inventory of Rock Glaciers in Himachal Himalaya, India Using High-Resolution Google Earth Imagery. Geomorphology 2019, 340, 103–115. [Google Scholar] [CrossRef]
  60. Majeed, Z.; Mehta, M.; Ahmad, M.; Mishra, R. Active rock glaciers of Jhelum basin, Kashmir Himalaya, India. Indian J. Geosci. 2022, 76, 107–124. [Google Scholar]
  61. Remya, S.N.; Ghosh, T.; Agarwal, V.; Majeed, Z.; Govindha Raj K, B.; Sharma, A.; Kulkarni, A.V.; Ahmad Mukhtar, M.; Mishra, R. A Framework to Identify Rock Glaciers and Model Mountain Permafrost in the Jhelum Basin, Kashmir Himalaya, India. Earth Sp. Sci. 2024, 11, e2023EA003170. [Google Scholar] [CrossRef]
  62. Romshoo, S.A.; Rafiq, M.; Rashid, I. Spatio-Temporal Variation of Land Surface Temperature and Temperature Lapse Rate over Mountainous Kashmir Himalaya. J. Mt. Sci. 2018, 15, 563–576. [Google Scholar] [CrossRef]
  63. Ali, I.; Shukla, A.; Romshoo, S.A. Assessing Linkages between Spatial Facies Changes and Dimensional Variations of Glaciers in the Upper Indus Basin, Western Himalaya. Geomorphology 2017, 284, 115–129. [Google Scholar] [CrossRef]
  64. Rashid, I.; Romshoo, S.A.; Abdullah, T. The Recent Deglaciation of Kolahoi Valley in Kashmir Himalaya, India in Response to the Changing Climate. J. Asian Earth Sci. 2017, 138, 38–50. [Google Scholar] [CrossRef]
  65. Dimri, A.P.; Mohanty, U.C. Simulation of Mesoscale Features Associated with Intense Western Disturbances over Western Himalayas. Meteorol. Appl. J. Forecast. Pract. Appl. Train. Tech. Model. 2009, 16, 289–308. [Google Scholar] [CrossRef]
  66. Mushtaq, F.; Pandey, A.C. Assessment of Land Use/Land Cover Dynamics Vis-à-Vis Hydrometeorological Variability in Wular Lake Environs Kashmir Valley, India Using Multitemporal Satellite Data. Arab. J. Geosci. 2014, 7, 4707–4715. [Google Scholar] [CrossRef]
  67. Zaz, S.N.; Romshoo, S.A.; Krishnamoorthy, R.T.; Viswanadhapalli, Y. Analyses of Temperature and Precipitation in the Indian Jammu and Kashmir Region for the 1980–2016 Period: Implications for Remote Influence and Extreme Events. Atmos. Chem. Phys. 2019, 19, 15–37. [Google Scholar] [CrossRef]
  68. Romshoo, S.A.; Abdullah, T.; Bhat, M.H. Evaluation of the Global Glacier Inventories and Assessment of Glacier Elevation Changes over North-Western Himalaya. Earth Syst. Sci. Data Discuss. 2021, 2021, 1–45. [Google Scholar] [CrossRef]
  69. Mukherjee, S.; Joshi, P.K.; Mukherjee, S.; Ghosh, A.; Garg, R.D.; Mukhopadhyay, A. Evaluation of Vertical Accuracy of Open Source Digital Elevation Model (DEM). Int. J. Appl. Earth Obs. Geoinf. 2013, 21, 205–217. [Google Scholar] [CrossRef]
  70. Paul, O.J.; Romshoo, S.A.; Dar, R.A.; Kumar, P.; Dhal, S.P.; Chopra, S. Paleo-Glacial Reconstruction of the Thajwas Glacier in the Kashmir Himalaya Using 10Be Cosmogenic Radionuclide Dating. Geosci. Front. 2022, 13, 101432. [Google Scholar] [CrossRef]
  71. Paul, F.; Frey, H.; Le Bris, R. A New Glacier Inventory for the European Alps from Landsat TM Scenes of 2003: Challenges and Results. Ann. Glaciol. 2011, 52, 144–152. [Google Scholar] [CrossRef]
  72. Frey, H.; Paul, F. On the Suitability of the SRTM DEM and ASTER GDEM for the Compilation of Topographic Parameters in Glacier Inventories. Int. J. Appl. Earth Obs. Geoinf. 2011, 18, 480–490. [Google Scholar] [CrossRef]
  73. Wu, Y.; He, J.; Guo, Z.; Chen, A. Limitations in Identifying the Equilibrium-Line Altitude from the Optical Remote-Sensing Derived Snowline in the Tien Shan, China. J. Glaciol. 2014, 60, 1093–1100. [Google Scholar]
  74. Haireti, A.; Tateishi, R.; Alsaaideh, B.; Gharechelou, S. Multi-Criteria Technique for Mapping of Debris-Covered and Clean-Ice Glaciers in the Shaksgam Valley Using Landsat TM and ASTER GDEM. J. Mt. Sci. 2016, 13, 703–714. [Google Scholar] [CrossRef]
  75. Lu, Y.; Zhang, Z.; Shangguan, D.; Yang, J. Novel Machine Learning Method Integrating Ensemble Learning and Deep Learning for Mapping Debris-Covered Glaciers. Remote Sens. 2021, 13, 2595. [Google Scholar] [CrossRef]
  76. Kääb, A.; Weber, M. Development of Transverse Ridges on Rock Glaciers: Field Measurements and Laboratory Experiments. Permafr. Periglac. Process. 2004, 15, 379–391. [Google Scholar] [CrossRef]
  77. Baroni, C.; Carton, A.; Seppi, R. Distribution and behaviour of rock glaciers in the Adamello–Presanella Massif (Italian Alps). Permafr. Periglac. Process. 2004, 15, 243–259. [Google Scholar] [CrossRef]
  78. Haeberli, W.; Creep of Mountain Permafrost: Internal Structure and Flow of Alpine Rock Glaciers. Mitteilungen der Versuchsanstalt fur Wasserbau, Hydrol. und Glaziologie an der ETH Zurich. 1985, Nr 77. Available online: https://www.researchgate.net/profile/Wilfried-Haeberli/publication/303207487_Creep_of_mountain_permafrost_Internal_structure_and_flow_of_alpine_rock_glaciersmitteilungen_Der_versuchsanstalt_fur_wasserbau/links/5a04164aaca272b06ca78bfa/Creep-of-mountain-permafrost-Internal-structure-and-flow-of-alpine-rock-glaciersmitteilungen-Der-versuchsanstalt-fur-wasserbau.pdf (accessed on 2 March 2023).
  79. Barsch, D. Rockglaciers: Indicators for the Present and Former Geoecology in High Mountain Environments; Springer Science and Business Media: Berlin/Heidelberg, Germany, 2012. [Google Scholar]
  80. Ikeda, A.; Matsuoka, N. Degradation of Talus-derived Rock Glaciers in the Upper Engadin, Swiss Alps. Permafr. Periglac. Process. 2002, 13, 145–161. [Google Scholar] [CrossRef]
  81. Potter, J.N.; Steig, E.J.; Clark, D.H.; Speece, M.A.; Clark, G.T.; Updike, A.B. Galena Creek Rock Glacier Revisited-New Observations on an Old Controversy. Geogr. Ann. Ser. A Phys. Geogr. 1998, 80, 251–265. [Google Scholar] [CrossRef]
  82. Colucci, R.R.; Boccali, C.; Žebre, M.; Guglielmin, M. Rock Glaciers, Protalus Ramparts and Pronival Ramparts in the South-Eastern Alps. Geomorphology 2016, 269, 112–121. [Google Scholar] [CrossRef]
  83. Janke, J.R. Colorado Front Range Rock Glaciers: Distribution and Topographic Characteristics. Arctic, Antarct. Alp. Res. 2007, 39, 74–83. [Google Scholar] [CrossRef]
  84. Wahrhaftig, C.; Cox, A. Rock glaciers in the Alaska range. Geol. Soc. Am. Bull. 1959, 70, 383–436. [Google Scholar] [CrossRef]
  85. Pearson, K. Mathematical Contributions to the Theory of Evolution. Proc. R. Soc. Lond. 1897, 60, 273–283. [Google Scholar]
  86. Kim, T.K. T Test as a Parametric Statistic. Korean J. Anesthesiol. 2015, 68, 540–546. [Google Scholar] [CrossRef] [PubMed]
  87. Guglielmin, M.; Smiraglia, C. The Rock Glacier Inventory of the Italian Alps. In Proceedings of the Seventh International Conference on Permafrost, Yellowknife, NT, Canada, 23–27 June 1998 ; Volume 57, pp. 375–382. [Google Scholar]
  88. Harrison, S.; Whalley, B.; Anderson, E. Relict Rock Glaciers and Protalus Lobes in the British Isles: Implications for Late Pleistocene Mountain Geomorphology and Palaeoclimate. J. Quat. Sci. Publ. Quat. Res. Assoc. 2007, 23, 287–304. [Google Scholar] [CrossRef]
  89. Outcalt, S.I.; Benedict, J.B. Photo-Interpretation of Two Types of Rock Glacier in the Colorado Front Range, USA. J. Glaciol. 1965, 5, 849–856. [Google Scholar] [CrossRef]
  90. Kellerer-Pirklbauer, A.; Rieckh, M. Monitoring Nourishment Processes in the Rooting Zone of an Active Rock Glacier in an Alpine Environment. Z. Geomorphol. Suppl. Issues 2016, 60, 99–121. [Google Scholar] [CrossRef]
  91. Brenning a Climatic and Geomorphological Controls of Rock Glaciers in the Andes of Central Chile: Combining Statistical Modelling and Field Mapping; Humboldt-Universität zu Berlin: Berlin, Germany, 2005.
  92. Bodin, X.; Rojas, F. Brenning A Status and Evolution of the Cryosphere in the Andes of Santiago (Chile, 33.5°S). Geomorphology 2010, 118, 453–464. [Google Scholar] [CrossRef]
  93. Perucca, L. Esper Angillieri M Glaciers and Rock Glaciers’ Distribution at 28° SL, Dry Andes of Argentina, and Some Considerations about Their Hydrological Significance. Environ. Earth Sci. 2001, 64, 2079–2089. [Google Scholar] [CrossRef]
  94. Rangecroft, S.; Harrison, S. Anderson K Rock Glaciers as Water Stores in the Bolivian Andes: An Assessment of Their Hydrological Importance. Arctic Antarct. Alp. Res. 2015, 47, 89–98. [Google Scholar] [CrossRef]
  95. Cuffey, K.M.; Paterson, W.S.B. The Physics of Glaciers; Academic Press: Cambridge, MA, USA, 2010. [Google Scholar]
  96. Grinsted, A. An estimate of global glacier volume. Cryosphere 2013, 7, 141–151. [Google Scholar] [CrossRef]
  97. Angillieri, M.Y. Application of Frequency Ratio and Logistic Regression to Active Rock Glacier Occurrence in the Andes of San Juan, Argentina. Geomorphology 2010, 114, 396–405. [Google Scholar] [CrossRef]
  98. Janke JR, N.S. Bellisario A An Inventory and Estimate of Water Stored in Firn Fields, Glaciers, Debris-Covered Glaciers, and Rock Glaciers in the Aconcagua River Basin, Chile. Geomorphology 2017, 296, 142–152. [Google Scholar] [CrossRef]
  99. Brardinoni, F.; Scotti, R.; Sailer, R.; Mair, V. Evaluating Sources of Uncertainty and Variability in Rock Glacier Inventories. Earth Surf. Process. Landforms 2019, 44, 2450–2466. [Google Scholar] [CrossRef]
  100. Wang, X.; Liu, L.; Zhao, L.; Wu, T.; Li, Z.; Liu, G. Mapping and Inventorying Active Rock Glaciers in the Northern Tien Shan of China Using Satellite SAR Interferometry. Cryosphere 2017, 11, 997–1014. [Google Scholar] [CrossRef]
  101. Gruber, S. Derivation and Analysis of a High-Resolution Estimate of Global Permafrost Zonation. Cryosphere 2012, 6, 221–233. [Google Scholar] [CrossRef]
  102. Gruber, S.; Fleiner, R.; Guegan, E.; Panday, P.; Schmid, M.O.; Stumm, D.; Wester, P.; Zhang, Y.; Zhao, L. Inferring Permafrost and Permafrost Thaw in the Mountains of the Hindu Kush Himalaya Region. Cryosphere 2017, 13, 8. [Google Scholar] [CrossRef]
  103. Wani, J.M.; Thayyen, R.J.; Gruber, S.; Ojha, C.S.; Stumm, D. Single-Year Thermal Regime and Inferred Permafrost Occurrence in the Upper Ganglass Catchment of the Cold-Arid Himalaya, Ladakh, India. Sci. Total Environ. 2020, 703, 134631. [Google Scholar] [CrossRef] [PubMed]
  104. Selley, H.; Harrison, S.; Glasser, N.; Wündrich, O.; Colson, D.; Hubbard, A. Rock Glaciers in Central Patagonia. Geogr. Ann. Ser. A Phys. Geogr. 2019, 101, 1–15. [Google Scholar] [CrossRef]
  105. García, A.; Ulloa, C.; Amigo, G.; Milana, J.P.; Medina, C. An Inventory of Cryospheric Landforms in the Arid Diagonal of South America (High Central Andes, Atacama Region, Chile). Quat. Int. 2017, 438, 4–19. [Google Scholar] [CrossRef]
  106. Falaschi, D.; Tadono, T.; Masiokas, M. Rock Glaciers in the Patagonian Andes: An Inventory for the Monte San Lorenzo (Cerro Cochrane) Massif, 47 S. Geogr. Ann. Ser. A Phys. Geogr. 2015, 97, 769–777. [Google Scholar] [CrossRef]
  107. Hess, K.; Schmidt, S.; Nüsser, M.; Zang, C.; Dame, J. Glacier Changes in the Semi-Arid Huasco Valley, Chile, between 1986 and 2016. Geosciences 2020, 10, 429. [Google Scholar] [CrossRef]
  108. Uxa, T.; Mida, P. Rock Glaciers in the Western and High Tatra Mountains, Western Carpathians. J. Maps 2017, 13, 844–857. [Google Scholar] [CrossRef]
  109. Onaca, A.; Ardelean, F.; Urdea, P.; Magori, B. Southern Carpathian Rock Glaciers: Inventory, Distribution and Environmental Controlling Factors. Geomorphology 2017, 293, 391–404. [Google Scholar] [CrossRef]
  110. Seppi, R.; Carton, A.; Zumiani, M.; Dall’Amico, M.; Zampedri, G.; Rigon, R. Inventory, Distribution and Topographic Features of Rock Glaciers in the Southern Region of the Eastern Italian Alps (Trentino). Geogr. Fis. Din. Quat. 2012, 35, 185–197. [Google Scholar]
  111. Krainer, K.; Ribis, M. A Rock Glacier Inventory of the Tyrolean Alps (Austria). Austrian J. Earth Sci. 2012, 105, 32–47. [Google Scholar]
  112. Baral, P.; Haq, M.A. Yaragal S Assessment of Rock Glaciers and Permafrost Distribution in Uttarakhand. India. Permafr. Periglac. Process. 2020, 31, 31–56. [Google Scholar] [CrossRef]
  113. Romshoo, S.A.; Bashir, J.; Rashid, I. Twenty-First Century-End Climate Scenario of Jammu and Kashmir Himalaya, India, Using Ensemble Climate Models. Clim. Chang. 2020, 162, 1473–1491. [Google Scholar] [CrossRef]
  114. Salerno, F.; Thakuri, S.; Tartari, G.; Nuimura, T.; Sunako, S.; Sakai, A.; Fujita, K. Debris-Covered Glacier Anomaly? Morphological Factors Controlling Changes in the Mass Balance, Surface Area, Terminus Position, and Snow Line Altitude of Himalayan Glaciers. Earth Planet. Sci. Lett. 2017, 471, 19–31. [Google Scholar] [CrossRef]
  115. Vuille, M.; Franquist, E.; Garreaud, R.; Lavado Casimiro, W.S.; Cáceres, B. Impact of the Global Warming Hiatus on Andean Temperature. J. Geophys. Res. Atmos. 2015, 120, 3745–3757. [Google Scholar] [CrossRef]
  116. Palazzi, E.; Filippi, L.; Hardenberg, J. Insights into Elevation-Dependent Warming in the Tibetan Plateau-Himalayas from CMIP5 Model Simulations. Clim. Dyn. 2016, 48, 3991–4008. [Google Scholar] [CrossRef]
  117. Johnson, B.G.; Thackray, G.D.; Kirk, R. The Effect of Topography, Latitude, and Lithology on Rock Glacier Distribution in the Lemhi Range. Geomorphology 2007, 91, 38–50. [Google Scholar] [CrossRef]
  118. Onaca, A.; Ardelean, F.; Ardelean, A.; Magori, B.; Sirbu, F.; Voiculescu, M.; Gachev, E. Assessment of Permafrost Conditions in the Highest Mountains of the Balkan Peninsula. CATENA 2020, 185, 104288. [Google Scholar] [CrossRef]
  119. Abdullah, T.; Romshoo, S.A.; Rashid, I. The Satellite Observed Glacier Mass Changes over the Upper Indus Basin during 2000–2012. Sci. Rep. 2020, 10, 14285. [Google Scholar] [CrossRef]
  120. Dar, R.A.; Romshoo, S.A.; Chandra, R.; Ahmad, I. Tectono-Geomorphic Study of the Karewa Basin of Kashmir Valley. J. Asian Earth Sci. 2014, 92, 143–156. [Google Scholar] [CrossRef]
  121. Paul, O.J.; Dar, R.A.; Romshoo, S.A. Cirque Development in the Pir Panjal Range of North Western Himalaya, India. CATENA 2022, 213, 106179. [Google Scholar] [CrossRef]
  122. Clark, D.H.; Steig, E.J.; Potter, N., Jr.; Gillespie, A.R. Genetic Variability of Rock Glaciers. Geogr. Ann. Ser. A Phys. Geogr. 1998, 80, 175–182. [Google Scholar] [CrossRef]
  123. Cossart, E.; Fort, M.; Bourles, D.; Carcaillet, J.; Perrier, R.; Siame, L.; Braucher, R. Climatic Significance of Glacier Retreat and Rockglaciers Re-Assessed in the Light of Cosmogenic Dating and Weathering Rind Thickness in Clarée Valley (Briançonnais, French Alps). CATENA 2010, 80, 204–219. [Google Scholar] [CrossRef]
  124. Paul, O.J.; Dar, R.A.; Romshoo, S.A. Paleo-Glacial and Paleo-Equilibrium Line Altitude Reconstruction from the Late Quaternary Glacier Features in the Pir Panjal Range, NW Himalayas. Quat. Int. 2022, 642, 5–16. [Google Scholar] [CrossRef]
  125. Thakur, V.C.; Rawat, B.S. Geological Map of the Western Himalaya; Wadia Institute of Himalayan Geology: Dehradun, India, 1992. [Google Scholar]
  126. Brighenti, S.; Tolotti, M.; Bruno, M.C.; Wharton, G.; Pusch, M.T.; Bertoldi, W. Ecosystem Shifts in Alpine Streams under Glacier Retreat and Rock Glacier Thaw: A Review. Sci. Total Environ. 2019, 675, 542–559. [Google Scholar] [CrossRef] [PubMed]
  127. Berger, J.; Krainer, K.; Mostler, W. Dynamics of an Active Rock Glacier (Ötztal Alps, Austria). Quat. Res. 2004, 62, 233–242. [Google Scholar] [CrossRef]
  128. Marazi, A.; Romshoo, S.A. Streamflow Response to Shrinking Glaciers under Changing Climate in the Lidder Valley, Kashmir Himalayas. J. Mt. Sci. 2018, 15, 1241–1253. [Google Scholar] [CrossRef]
  129. Geiger, S.T.; Daniels, J.M.; Miller, S.N.; Nicholas, J.W. Influence of Rock Glaciers on Stream Hydrology in the La Sal Mountains, Utah. Arctic, Antarct. Alp. Res. 2014, 46, 645–658. [Google Scholar] [CrossRef]
  130. Bashir, J.; Romshoo, S.A. Bias-Corrected Climate Change Projections over the Upper Indus Basin Using a Multi-Model Ensemble. Environ. Sci. Pollut. Res. 2023, 30, 64517–64535. [Google Scholar] [CrossRef]
Figure 1. The figure shows the location of the study area, with circular dots representing rock glaciers (active, inactive, and relict) which are primarily concentrated in the Pir Panjal mountain range of the Jhelum basin. Additionally, the figure provides information on clean and debris-covered glaciers within the study area (Source: [68]).
Figure 1. The figure shows the location of the study area, with circular dots representing rock glaciers (active, inactive, and relict) which are primarily concentrated in the Pir Panjal mountain range of the Jhelum basin. Additionally, the figure provides information on clean and debris-covered glaciers within the study area (Source: [68]).
Water 16 02327 g001
Figure 2. The length, width, and elevation measurements of a rock glacier in the study area. Glacier widths were measured at ~50 m intervals perpendicular to the glacier length and were used to calculate mean widths of glaciers using GIS software. For representational purposes, the width lines in the figure are drawn at a wider interval of 130 m.
Figure 2. The length, width, and elevation measurements of a rock glacier in the study area. Glacier widths were measured at ~50 m intervals perpendicular to the glacier length and were used to calculate mean widths of glaciers using GIS software. For representational purposes, the width lines in the figure are drawn at a wider interval of 130 m.
Water 16 02327 g002
Figure 3. Characteristics of typical rock glaciers in the study area include a steep front, longitudinal and transversal ridges and furrows (a). A closer view of an active rock glacier reveals a swollen body with well-defined furrow and ridge topography, along with a steep, sharp-crested frontal slope (b). Inactive rock glaciers are characterized by prominent features such as a swollen body, subtle surface micro-topography, and gentler frontal slopes (c,d).
Figure 3. Characteristics of typical rock glaciers in the study area include a steep front, longitudinal and transversal ridges and furrows (a). A closer view of an active rock glacier reveals a swollen body with well-defined furrow and ridge topography, along with a steep, sharp-crested frontal slope (b). Inactive rock glaciers are characterized by prominent features such as a swollen body, subtle surface micro-topography, and gentler frontal slopes (c,d).
Water 16 02327 g003
Figure 4. Illustrations of two relict rock glaciers in the study area, highlighting surface depression or collapse structures, which are primary characteristics of relict glaciers and are clearly evident in the figure.
Figure 4. Illustrations of two relict rock glaciers in the study area, highlighting surface depression or collapse structures, which are primary characteristics of relict glaciers and are clearly evident in the figure.
Water 16 02327 g004
Figure 5. An example of a rock glacier mapped independently by eight different analysts.
Figure 5. An example of a rock glacier mapped independently by eight different analysts.
Water 16 02327 g005
Figure 6. Distribution of rock glaciers across various elevations in the study area.
Figure 6. Distribution of rock glaciers across various elevations in the study area.
Water 16 02327 g006
Figure 7. Distribution of rock glaciers and their corresponding areas across various slope categories in the study area.
Figure 7. Distribution of rock glaciers and their corresponding areas across various slope categories in the study area.
Water 16 02327 g007
Figure 8. Aspect-wise frequency distribution and area of rock glaciers (km2) in the study area.
Figure 8. Aspect-wise frequency distribution and area of rock glaciers (km2) in the study area.
Water 16 02327 g008
Figure 10. (a) A rock glacier situated adjacent to a stream and (b) a military road traversing through a rock glacier in the Gulmarg area of the Pir Panjal range in the study area.
Figure 10. (a) A rock glacier situated adjacent to a stream and (b) a military road traversing through a rock glacier in the Gulmarg area of the Pir Panjal range in the study area.
Water 16 02327 g010
Table 1. Details of image sources and acquisition dates accessed through the Google Earth platform and utilized for rock glacier mapping in the Jhelum basin.
Table 1. Details of image sources and acquisition dates accessed through the Google Earth platform and utilized for rock glacier mapping in the Jhelum basin.
Image SourceAcquisition DateRock Glacier Mapped
Maxar Technologies
Westminster, CO, USA
4 October 20115
CNES/AIRBUS21 October 20137
Maxar Technologies21 September 20149
22 November 2014
CNES/AIRBUS9 June 20162
CNES/AIRBUS3 October 2017210
6 November 2017
11 November 2017
12 November 2017
29 October 2017
30 October 2017
31 October 2017
Maxar Technologies17 October 2017
Maxar Technologies14 September 20184
17 October 20203
Table 2. Geomorphic indicators used as criteria for identifying and mapping rock glaciers in the study area.
Table 2. Geomorphic indicators used as criteria for identifying and mapping rock glaciers in the study area.
Geomorphic Indicator Intact Rock GlaciersRelict
ActiveInactive
Surface flow Structure Defined furrow and ridge topography
[56,76,78,79]
Relatively subdued micro-topography [53,57,79,80]Less defined furrow and ridge topography [76]
Rock Glacier Body Swollen body [77]
Surface ice exposures[81]
Can have swollen body and surface ice exposures [77,81] Flattened body [77]
Surface collapse features [82,83]
Front Slope Steep (~>30–35°) [53]
Abrupt transition (sharp-crested) to the upper surface [84]
Light-colored (little clast weathering) frontal zone, and a darker varnished upper surface [44]
Generally gentler slopes [26,53]
Dark-coloured rock-varnished frontal slopes [44,80]
Gently sloping (~<30°) [77]
Gentle transition (i.e., round-crested) to the upper surface [84]
Table 3. Description of various rock glacier attributes.
Table 3. Description of various rock glacier attributes.
AttributeAttribute Explanation
IDUnique identification number (e.g., RG-124)
Mountain Range[PR] PirPanjal, [GH] Greater Himalayas
LonLongitudinal coordinate of polygon centroid (DDD.ddd [N])
LatLatitudinal coordinate of polygon centroid (DD.ddd [E])
MEF (m asl)Minimum elevation at the front
MaxE (m a.s.l.)Maximum elevation of the feature
MeanE (m a.s.l.)
Slope (°)
Mean elevation of the feature
Range|Mean
Area (km2)/
Aspect ClassN, NE, E, SE, S, SW, W, NW (e.g., 90° = E, 180° = S)
Length (m)Maximum length of the landform
Width (m)Mean width of the landform
L:W RatioLength:width ratio
GeometryTongue-shaped, lobate-shaped
StatusActive, inactive, relict
Table 4. Distribution (count, area) and general topographic characteristics of rock glaciers across various glacier size categories in the study area.
Table 4. Distribution (count, area) and general topographic characteristics of rock glaciers across various glacier size categories in the study area.
Area (km2)
Size Category (km2)CountMeanTotalMean Elevation
(m asl)
Mean Slope (°)
<0.10124 (51.66%)0.045.51 ± 0.3
(13.35%)
4011 ± 19820.92
0.1–0.599 (41.25%)0.2322.8 ± 1.2 (55.29%)3989 ± 19418.53
>0.517
(7.08%)
0.7612.93 ± 0.6 (31.25%)3988 ± 19218.45
Table 5. Basic information regarding number, area, activity, topographic, and morphological characteristics of rock glaciers mapped in the study area.
Table 5. Basic information regarding number, area, activity, topographic, and morphological characteristics of rock glaciers mapped in the study area.
Area (km2)Elevation (m asl)
StatusCountMinMaxMeanTotalMAFMaxEMeanEMean Slope
(°)
Mean Max Length (m)
Active183 (76.25%)0.011.040.1935.55 ± 1.8 (86.18%)3481 ± 1454485 ± 2754015 ± 19619.64699.44
Inactive48 (20.0%)0.000.350.063.1 ± 0.2
(7.52%)
3672 ± 1464349 ± 2764010 ± 19720.99426.50
Relict9
(3.75%)
0.020.640.292.59 ± 0.1
(6.28%)
3316 ± 1313939 ± 2473650 ± 17715.71952.98
Table 6. Distribution of rock glaciers across various elevation and slope categories in the study area. The values in parentheses represent the percentage count and rock glacier coverage within each elevation and slope category.
Table 6. Distribution of rock glaciers across various elevation and slope categories in the study area. The values in parentheses represent the percentage count and rock glacier coverage within each elevation and slope category.
Elevation (m asl)
Area (km2)
CategoryCountMinMaxMeanTotal
3500–4000107 (44.5%)0.0031.040.1920.96 ± 1.1 (50.82%)
4000–4500133 (55.4%)0.0081.030.1520.28 ± 1.1 (49.17%)
Slope (°)
10–1530 (12.50%)0.020.780.195.64 ± 0.3 (13.67%))
15–20104 (43.33%)0.011.040.2122.15 ± 1.2 (58.68%)
20–2579 (32.92%)0.010.970.1512.12 ± 0.6 (29.37%)
25–3018 (7.50%)0.000.180.061.09 ± 0.06 (2.64%)
30–359 (3.75%)0.010.060.030.26 ± 0.01 (0.64%)
Table 7. Aspect-wise morphological and topographical characteristics of rock glaciers in the study area.
Table 7. Aspect-wise morphological and topographical characteristics of rock glaciers in the study area.
Elevation (m asl)Slope (°)Area (km2)Length (m)
AspectCountMinMaxMeanMinMaxMeanMinMaxMeanTotalMinMaxMean
E2
(0.83%)
3921 ± 1454202 ± 2744062 ± 19615.5019.7617.630.440.650.551.10 ± 0.1
(2.65%)
1404.181445.781424.98
N215
(89.58%)
3574 ± 1454301 ± 2743995 ± 1979.0535.4919.650.001.040.1735.69 ± 0.6
(86.51%)
90.872163.59630.34
S12
(5.0%)
3825 ± 1494315 ± 2824149 ± 20213.1431.1721.490.020.970.202.42 ± 0.1
(5.87%)
134.001680.02718.22
W11
(4.58%)
3504 ± 1414177 ± 2673937 ± 19014.4724.1820.400.020.390.192.0 ± 40.1
(2.95%)
281.151513.85914.17
Table 8. Characteristics of rock glacier inventories reported from various regions of the world.
Table 8. Characteristics of rock glacier inventories reported from various regions of the world.
Study Area *NumberArea (km2)ActivityMin.
Elevation
(m asl)
Max.
Elevation
(m asl)
Mean
Elevation
(m asl)
Source
North America
Colorado Front Range (North America)220 19.9Active
Inactive
Relict
3525
3424
3227
3668
3541
3358
3594
3477
3288
[83]
South America
Central Patagonia8914.18Intact
Relict
1766
1758
1941
1919
-
-
[104]
Aconcagua River Basin 66970.0All237045653810[98]
Central Andes (Atacama region) 47744.34All380755044427[105]
Volcán Domuyo region, southernmost Central Andes 22417.7Active
Inactive
Relict
2664
2165
1955
3968
3526
3340
3047
2821
2644
[106]
Monte San Lorenzo massif17711.31Intact
Relict
1335
1267
2155
2030
1742
1590
[106]
Valles Calchaquíes Region48858.5Intact
Relict
4183
4072
5908
5397
4873
4695
[106]
Huasco Valley, Chile508.6All384050704220[107]
Europe
Western Tatra Mts.1837.14Intact
Relict
1812
1644
-
-
-
-
[108]
High Tatra Mts.2006.7Intact
Relict
2011
1731
-
-
-[108]
Southern Carpathian30612.7All--1998[109]
Southern region of the eastern Italian Alps70533.3Intact
Relict
2716
1644
3082
2669
2632
2169
[110]
South-eastern Alps533.45All--1778[82]
Tyrolean Alps3145167.2Active 262827972704[111]
Inactive254226652598
Relict227923842330
Asia
Nepalese Himalaya6239249.83Intact
Relict
4977
4541
5215
4738
-
-
[30]
Himachal Himalaya516353All44844900-[59]
TienShan of China26191.5All31743486-[100]
Daxue Shan, southeastern Tibetan Plateau29555.70All4352-4471[58]
Central Himalaya37028.9All400060005100[41]
Uttarakhand, Central Himalaya1004172.06All382158224742[112]
Jhelum Basin, Kashmir Himalaya20748.23Active
Relict
3591
3573
4461
4588
4026
4057
[61]
Jhelum Basin, Kashmir Himalaya23148.46Active30194633-[60]
Jhelum basin
Northwestern Himalaya
24041.24Active
Inactive
Relict
3481
3672
3316
4485
4349
3939
4015
4010
2650
Present study
Note(s): * The table contains only those studies that provide data on rock glacier numbers, area, and at least one of the three elevation parameters (i.e., minimum, maximum, or mean).
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Abdullah, T.; Romshoo, S.A. A Comprehensive Inventory, Characterization, and Analysis of Rock Glaciers in the Jhelum Basin, Kashmir Himalaya, Using High-Resolution Google Earth Data. Water 2024, 16, 2327. https://doi.org/10.3390/w16162327

AMA Style

Abdullah T, Romshoo SA. A Comprehensive Inventory, Characterization, and Analysis of Rock Glaciers in the Jhelum Basin, Kashmir Himalaya, Using High-Resolution Google Earth Data. Water. 2024; 16(16):2327. https://doi.org/10.3390/w16162327

Chicago/Turabian Style

Abdullah, Tariq, and Shakil Ahmad Romshoo. 2024. "A Comprehensive Inventory, Characterization, and Analysis of Rock Glaciers in the Jhelum Basin, Kashmir Himalaya, Using High-Resolution Google Earth Data" Water 16, no. 16: 2327. https://doi.org/10.3390/w16162327

APA Style

Abdullah, T., & Romshoo, S. A. (2024). A Comprehensive Inventory, Characterization, and Analysis of Rock Glaciers in the Jhelum Basin, Kashmir Himalaya, Using High-Resolution Google Earth Data. Water, 16(16), 2327. https://doi.org/10.3390/w16162327

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop