Search Results (7)

Over the past decades, the cryosphere has changed significantly in High Mountain Asia (HMA), leading to multiple natural hazards such as rock–ice avalanches, glacier collapse, debris flows, landslides, and glacial lake outburst floods (GLOFs). Monitoring cryosphere change and evaluating its hydrological effects are essential for studying climate change, the hydrological cycle, water resource management, and natural disaster mitigation and prevention. However, knowledge gaps, data uncertainties, and other substantial challenges limit comprehensive research in climate–cryosphere–hydrology–hazard systems. To address this, we provide an up-to-date, comprehensive, multidisciplinary review of remote sensing techniques in cryosphere studies, demonstrating primary methodologies for delineating glaciers and measuring geodetic glacier mass balance change, glacier thickness, glacier motion or ice velocity, snow extent and water equivalent, frozen ground or frozen soil, lake ice, and glacier-related hazards. The principal results and data achievements are summarized, including URL links for available products and related data platforms. We then describe the main challenges for cryosphere monitoring using satellite-based datasets. Among these challenges, the most significant limitations in accurate data inversion from remotely sensed data are attributed to the high uncertainties and inconsistent estimations due to rough terrain, the various techniques employed, data variability across the same regions (e.g., glacier mass balance change, snow depth retrieval, and the active layer thickness of frozen ground), and poor-quality optical images due to cloudy weather. The paucity of ground observations and validations with few long-term, continuous datasets also limits the utilization of satellite-based cryosphere studies and large-scale hydrological models. Lastly, we address potential breakthroughs in future studies, i.e., (1) outlining debris-covered glacier margins explicitly involving glacier areas in rough mountain shadows, (2) developing highly accurate snow depth retrieval methods by establishing a microwave emission model of snowpack in mountainous regions, (3) advancing techniques for subsurface complex freeze–thaw process observations from space, (4) filling knowledge gaps on scattering mechanisms varying with surface features (e.g., lake ice thickness and varying snow features on lake ice), and (5) improving and cross-verifying the data retrieval accuracy by combining different remote sensing techniques and physical models using machine learning methods and assimilation of multiple high-temporal-resolution datasets from multiple platforms. This comprehensive, multidisciplinary review highlights cryospheric studies incorporating spaceborne observations and hydrological models from diversified techniques/methodologies (e.g., multi-spectral optical data with thermal bands, SAR, InSAR, passive microwave, and altimetry), providing a valuable reference for what scientists have achieved in cryosphere change research and its hydrological effects on the Third Pole. Full article

This research presents a comprehensive environmental assessment of a small mountain permafrost catchment of the Anmangynda River in the Upper Kolyma Highland (Northeastern Asia) over the period of 2021–2023. The study reveals significant diversity in climatic, geocryological, and hydrogeological conditions within this confined area, emphasizing the need for extensive field data collection and monitoring in vast permafrost regions with limited data availability. Key findings include variations in ground temperature, maximum seasonal thaw depth, and depths of zero annual amplitudes of ground temperature at different elevations and landscape types. Groundwater and surface flow dynamics within spring aufeis basins exhibit complex geocryological regimes influenced by icing processes. The presence of aufeis and its impact on local hydrology highlight the ecological significance of this phenomenon. Future research should focus on long-term trends in permafrost dynamics and their relationship with climate change, as well as the ecological effects of aufeis formation on local ecosystems. The study underscores the importance of a multi-faceted approach to environmental assessment, incorporating various environmental parameters and processes, to gain a comprehensive understanding of the intricate interactions within the cryosphere and their responses to changing climate conditions. Such knowledge is essential for addressing broader questions related to climate change, ecosystem resilience, and sustainable resource management in Northeastern Siberia. Full article

Cryosphere studies in High Mountain Asia (HMA) typically focus on glaciers, seasonal snow cover, and permafrost. As an additional and mostly overlooked cryosphere component, aufeis occurs frequently in cold-arid regions and covers extensive areas of the Trans-Himalaya and Tibetan Plateau. This largely neglected cryosphere component generally forms in winter from repeated freezing of seepage or overflow. In this article, the occurrence of aufeis fields in the endorheic Pangong Tso Basin (PTB), with a total area of 31,000 km², is inventoried and examined. Based on a semi-automatic remote sensing approach using Sentinel-2 imagery, about 1000 aufeis fields were detected in the spring of 2019, covering a total area of approximately 86 km² and with an average individual size of 0.08 km², while the largest field covered an area of 14.8 km². A striking contrast between the northern and southern portions of the PTB characterized the spatial distribution of large aufeis fields. All large (>0.5 km²) and 13 persisting aufeis fields were located along broad valleys in the northern portion. Furthermore, a multi-temporal comparison between 1994 and 2023 shows that the number of remaining aufeis fields in autumn varied between 8 and 29, with a maximum in 2019. Their total area ranged between about 0.3 km² in 1994 and 2023 to about 1.2 km² in 2015 and 2019. This study complements recent aufeis inventories from the Trans-Himalayan region of Ladakh and closes the gap to the Tibetan Plateau. Full article

Gigantic aufeis fields serve as indicators of water exchange processes within the permafrost zone and are important in assessing the state of the cryosphere in a changing climate. The Anmangynda aufeis, located in the upstream of the Kolyma River basin, is present in the mountainous regions of Northeast Eurasia. Recent decades have witnessed significant changes in aufeis formation patterns, necessitating a comprehensive understanding of cryospheric processes. The objective of the study, conducted in 2021–2022, was to examine the structure of the Anmangynda aufeis and its glade, aiming to understand its genesis and formation processes. The tasks included identifying above- and intra-frozen taliks, mapping groundwater (GW) discharge channels, determining permafrost base depth, and assessing ice thickness distribution. Soundings using ground-penetrating radar (GPR), capacitively coupled electrical resistivity tomography (CCERT), and the transient electromagnetic (TEM) method were employed. GW discharge channels originating from alluvial deposits and extending to the aufeis surface within river channels were identified through GPR and verified through drilling. Deep-seated sources of GW within the bedrock were inferred. CCERT data allowed us to identify large and localized frozen river taliks, from which water is forced onto the ice surface. According to the TEM data, the places of GW outlets spatially coincide with the zones interpreted as faults. Full article

Based on the analysis of Landsat satellite images over the period of 2013–2019, the number (6683) and total area (4529 km²) of giant aufeis fields (area ≥ 0.1 km²) were estimated for the territory of North-Eastern Eurasia. The contribution of aufeis runoff to river streamflow in different seasons was calculated for 58 hydrological gauges (area 523–526,000 km²). The contribution of aufeis and glaciers to water balance is compared. The aufeis resources vary from 0.4 to 4.25 km³ (or 3.7–11 mm) for individual basins of large rivers. They are at least 10.6 km³ in total or 5 mm of water depth on average for the study area. Aufeis annual runoff varies from 0.3 to 29 mm (0.1–22%, average 3.8%), with the share in winter runoff amount about 6–712% (average 112%) and the spring freshet 0.2–43% (average 7.1%). In general, the aufeis runoff exceeds the glacial runoff. The dynamics of aufeis formation are directly related to winter runoff, whose changes are observed in different parts of the cryosphere. The presented results are relevant for studying the impact of climate change on the hydrological cycle and its components in the permafrost regions of the Northern Hemisphere. Full article

Icing/Aufeis processes are a typical feature of permafrost hydrology in mountainous regions. Regional databases of Aufeis have been compiled since the 2010. In this study, we attempted to create an initial Aufeis database for the Qinghai-Tibet Plateau (QTP) to evaluate the patterns of the icing processes in the arid and high mountain regions at low latitudes. In this article, the icings/Aufeis in the Kunlun Mountains on the northern edge of the QTP were investigated. A total of 65 Landsat 8 Operational Land Imager images for 2017–2020 of the key sites were acquired. Icings occur at elevations of 2500–5400 m a. s. l. More than 1600 Aufeis were identified with a total ice-surface area of 2670 km². About 88% of these areas are related to a gigantic Aufeis (tarin) field. Artesian aquifers related to the active faults play an important role in feeding the Aufeis in the Kunlun Mountains. About 120 Aufeis fed on glacier-melt have formed in the West Kunlun Mountains. Icing development was found to vary with the order of river channels and more than half of all of the identified Aufeis are located along first- and second-order river channels. The significance of Aufeis at the QTP related to as an indicator of climate change, and a volume of surface and ground waters conserved into Aufeis should take into consideration of river runoff estimation of the region. Full article

Mongolia is a semi-arid, highly continental region with highly variable precipitation and river discharge. The groundwater aquifer located near Ulaanbaatar, the capital city of Mongolia, is the only one source for city water supply consumption, and it is important to ensure that groundwater is available now and in the future. The main watercourse near the capital city is the Tuul River, fed by precipitation in the Khentii Mountains. The semi-arid and cold environment shows high variability in precipitation and river discharge. However, due to absence of precipitation in winter and spring, the riverbed usually runs dry during these times of the year, and weather observations show that the dry period has been extending in recent years. However, in parallel with urban development, the extended groundwater aquifer has shown a clear decline, and the groundwater levels have dropped significantly. Therefore, a groundwater management system based on managed aquifer recharge is proposed, and a strategy to implement these measures in the Tuul River valley is presented in this paper. This strategy consists of the enhancement of natural recharge rates during the wet summer from the northern drainage canal, an additional increase in groundwater recharge through melting the ice storage in the dry period, as well as the construction of underground dams to accumulate groundwater and a surface water reservoir that releases a constant discharge in the outlet. To increase natural recharge rates of groundwater during the early dry period through the melting ice storage period, the MATLAB icing code, which was written for ice storage for limited and unlimited areas, was considered through finite element subsurface FLOW (FEFLOW) simulation scenarios as a water source in ice form on the surface. A study of the artificial permafrost of underground as an ice dam was processed in FEFLOW simulation scenarios for accumulating groundwater resources. The results of these artificial recharging methods were individually calculated, combined, and compared with the surface reservoir, which releases a constant discharge through the dam. In this paper, new ideas are presented involving managed aquifer recharge—MAR methods, and include application to aufeis, a mass of layered ice for groundwater recharge by melting. Additionally, the accumulation of groundwater using artificial permafrost is used as an underground dam. In addition, was considered recharging scenario only with constant release water amount from water reservoir also with all MAR methods together with reservoir combination. Full article