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Keywords = mixing zone of river and sea waters

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30 pages, 7008 KiB  
Article
Microfossil (Diatoms, Tintinnids, and Testate Amoebae) Assemblages in the Holocene Sediments of the Laptev Sea Shelf off the Yana River as a Proxy for Paleoenvironments
by Maria S. Obrezkova, Lidiya N. Vasilenko, Ira B. Tsoy, Xuefa Shi, Limin Hu, Yaroslav V. Kuzmin, Aleksandr N. Kolesnik, Alexandr V. Alatortsev, Anna A. Mariash, Evgeniy A. Lopatnikov, Irina A. Yurtseva, Darya S. Khmel and Anatolii S. Astakhov
Quaternary 2025, 8(3), 40; https://doi.org/10.3390/quat8030040 - 30 Jul 2025
Viewed by 214
Abstract
The paper presents the results of a microfossil study of Holocene sediments in the Yana River flow zone in the southeastern part of the Laptev Sea. A rich diatom flora (242 species and intraspecific taxa, of which 177 species are freshwater) was revealed; [...] Read more.
The paper presents the results of a microfossil study of Holocene sediments in the Yana River flow zone in the southeastern part of the Laptev Sea. A rich diatom flora (242 species and intraspecific taxa, of which 177 species are freshwater) was revealed; additionally, five species of marine tintinnids (planktonic ciliates) and 15 species of freshwater testate amoebae (testacean) were discovered for the first time in the sea sediments. Three assemblages of microfossils reflecting the phases of environmental changes during the Holocene transgression are distinguished in the studied sediments of core LV83-32. Assemblage 1 was formed under terrestrial conditions (assemblage of diatoms Eunotia-Pinnularia and testacean Difflugia-Cylindrifflugia-Centropyxis), assemblage 2 in the zone of mixing of sea and fresh waters (assemblages of diatoms Cyclotella striata-Aulacoseira, Thalassiosira hyperborea-Chaetoceros and T. hyperborea-Aulacoseira, testacean Cyclopyxis kahli, tintinnids Tintinnopsis fimbriata), and assemblage 3 reflects modern conditions in the inner shelf of the Laptev Sea under the strong influence of river runoff (assemblage of diatoms T. hyperborea-Aulacoseira-M. arctica and tintinnids Tintinnopsis ventricosoides). Changes in the natural environment in the coastal part of the Laptev Sea shelf during the Holocene, established by microfossil assemblages, are confirmed by geochemical data. Full article
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24 pages, 10807 KiB  
Article
Pollution and Ecological Risk Assessment of Potentially Toxic Elements in Sediments Along the Fluvial-to-Marine Transition Zone of the Don River
by Elizaveta Konstantinova, Tatiana Minkina, Dina Nevidomskaya, Tatiana Bauer, Inna Zamulina, Elizaveta Latsynnik, Tamara Dudnikova, Rajendra Kumar Yadav, Marina Burachevskaya and Saglara Mandzhieva
Water 2024, 16(22), 3200; https://doi.org/10.3390/w16223200 - 7 Nov 2024
Cited by 1 | Viewed by 1439
Abstract
The quality of sediments in the mixing zone of river freshwater and marine saline water as an important geochemical barrier for potentially toxic elements (PTEs) remains poorly understood. This study aims to analyze the current pollution with PTEs and associated ecological risks in [...] Read more.
The quality of sediments in the mixing zone of river freshwater and marine saline water as an important geochemical barrier for potentially toxic elements (PTEs) remains poorly understood. This study aims to analyze the current pollution with PTEs and associated ecological risks in sediments of the Don River delta and the surrounding area of the Taganrog Bay of the Sea of Azov (Russia). The PTE content was determined in fifty-four collected samples using the WDXRF and assessed using geochemical and ecotoxicological indicators. The source of Cr, Mn, Ni and Pb is mainly river runoff, and Cu, Zn and Cd are from a variety of anthropogenic sources. As shown by the assessment of the geoaccumulation index (Igeo), single pollution index (PI) and contamination factor (CF), these elements are the priority pollutants. According to these estimates, high and very high contamination of sediments in the estuarine zone of the Don River with Cd and Pb was detected in 72–94% and 2–57% of samples, respectively. However, environmental risks are determined almost exclusively by the level of Cd. Total contamination as assessed by the Nemerow pollution index (NPI), modified degree of contamination (mCd) and metal pollution index (MPI) is of concern in 83–98% of the samples studied. The most heavily polluted sediments are in the vicinity of residential areas of the Taganrog Bay. Despite the lower average pollution levels of deltaic sediments, freshwater biota are exposed to higher potential toxic risks of adverse effects by PTE, particularly from Ni and Pb. Thus, the complex hydrological regime and uneven anthropogenic impact predetermine the geochemical state of the sediments of the estuarine zone of the Don River. Full article
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21 pages, 7431 KiB  
Article
A Dynamic Estuarine Classification of the Vertical Structure Based on the Water Column Density Slope and the Potential Energy Anomaly
by Jagoba Lupiola, Javier F. Bárcena, Javier García-Alba and Andrés García
Water 2023, 15(18), 3294; https://doi.org/10.3390/w15183294 - 18 Sep 2023
Cited by 2 | Viewed by 3094
Abstract
The aim of this work is to develop a new estuarine classification attending to their vertical structure by examining the advantages and disadvantages of the existing classifications. For this purpose, we reviewed the main classifications, finding that most of them analyze the entire [...] Read more.
The aim of this work is to develop a new estuarine classification attending to their vertical structure by examining the advantages and disadvantages of the existing classifications. For this purpose, we reviewed the main classifications, finding that most of them analyze the entire estuary as a unique water body without considering the spatiotemporal variability of the mixing zone in estuaries. Furthermore, the proposed classifications require the calculation of parameters that are not easily measurable, such as tidal current amplitude. Thus, we developed a new classification based on density profile slopes of the water column, which has been correlated to the potential energy anomaly. To test this classification, the proposed method was applied to the Suances estuary (Spain) during the year 2020 and to analyze the potential estuarine modifications under four climate change projections (RCP 4.5 and 8.5 for the years 2050 and 2100). To carry out this study, a calibrated and validated high-resolution horizontal and vertical 3D model was used. The application showed a high variability in the vertical structure of the estuary due to the tide and river. According to the proposed classification, the well mixed category was predominant in the estuary in 2020 and tended to grow in the projections of climate change. As a result, the fully mixed and weakly stratified mixing classes were reduced in the projected scenarios due to a decrease of external forcing, such as river flow and sea level rise. Furthermore, areas classified as stratified tended to move upstream of the estuary. Full article
(This article belongs to the Section Oceans and Coastal Zones)
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10 pages, 1364 KiB  
Data Descriptor
Biodiversity of Marine Interstitial Ciliates in the Intertidal Zone of the White Sea: A Dataset from the Chernaya River Estuary, Kandalaksha Gulf
by Xiaolei Li, Anton S. Esaulov, Igor V. Burkovsky, Damir A. Saldaev and Yuri A. Mazei
Diversity 2023, 15(7), 873; https://doi.org/10.3390/d15070873 - 19 Jul 2023
Cited by 1 | Viewed by 1672
Abstract
(1) Background: An estuary is a zone in which sea and river waters mix. It is a specific area with a very non-stable environment and salinity gradient. However, little is known about the diversity of ciliate communities in estuarine benthic ecosystems in the [...] Read more.
(1) Background: An estuary is a zone in which sea and river waters mix. It is a specific area with a very non-stable environment and salinity gradient. However, little is known about the diversity of ciliate communities in estuarine benthic ecosystems in the Arctic. The aim of this paper is to describe the diversity of intertidal ciliates in the Chernaya river estuary (Kandalaksha Gulf, White Sea), which is characterized by a pronounced salinity gradient (0–22‰), on the basis of a recently published dataset. (2) Methods: We conducted our own investigations during the summer periods of 1998–2000. Material was collected at five permanent stations along the salinity gradient (0–22%) of the estuary. For each observation, the coordinates of the sampling sites, the number of individuals observed and the sampling date were recorded. The total effort comprised 35 sampling days, with five sampling sites at each date. (3) Results: The dataset contains 4270 unique occurrences of 119 ciliates taxa (109 species, 8 unidentified species of the genus level and 2 unidentified species on the family level). The total number of specimens represented is 64,475. (4) Conclusions: The largest classes in terms of species diversity are Hypotrichea (27 species), Gymnostomatea (26 species), Oligohymenophorea (17 species) and Karyorelictea (16 species). Full article
(This article belongs to the Special Issue Biodiversity of Invertebrates)
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22 pages, 4890 KiB  
Article
Modulation of the Marine Environment in the Natal Bight
by Mark R. Jury
Remote Sens. 2023, 15(5), 1434; https://doi.org/10.3390/rs15051434 - 3 Mar 2023
Cited by 1 | Viewed by 1814
Abstract
Modulation of the marine environment in the Natal Bight (~29.1°S, 31.6°E) was studied using daily high-resolution climate reanalysis products and monthly satellite green- and red-band reflectance in the period 2002–2022. The KwaZulu-Natal shelf edge is characterized by a narrow band of upwelling next [...] Read more.
Modulation of the marine environment in the Natal Bight (~29.1°S, 31.6°E) was studied using daily high-resolution climate reanalysis products and monthly satellite green- and red-band reflectance in the period 2002–2022. The KwaZulu-Natal shelf edge is characterized by a narrow band of upwelling next to the warm Agulhas Current. Strong, reversing longshore winds ~7 m/s and meandering poleward flow ~1 m/s pulse the system, but along the leeward coast that forms the Natal Bight, environmental conditions are buffered by a weak cyclonic gyre. Wind and current shear create a shadow zone that aggregates plankton, recycles nutrients, and sustains marine resources. The seasonal cycle is of high amplitude: the surface heat balance reaches +70 W/m2 in December, followed by river discharges ~3 M m3/yr of fresh nutrient-rich water that peak in February. This induces a buoyant surface layer that inhibits wind wave turbulence during summer. By contrast, winter (June–August) cooling −95 W/m2 and frequent cyclonic storminess deepen the mixed layer from 25 to 65 m, enabling wind wave turbulence to reach the seafloor (Tugela Bank). Red-band reflectance increases 3-fold from summer to winter and is significantly correlated with net heat balance −0.54, daily wave heights > 2.5 m +0.51, mixed layer depth +0.47, sea surface temp −0.41, and wind vorticity −0.39. Daily longshore winds from the northeast and southwest were, unexpectedly, most amplified in spring (August–October). The seasonality exhibits sequential effects that supports year-round marine nutrification in the Natal Bight. Intra-seasonal fluctuations were related to meandering of the Agulhas Current and changes in longshore winds and shelf waves that impart significant pulsing of near-shore currents at 4–9-day periods. Although the cyclonic gyre in the Natal Bight spins up and down, SST variance was found to be relatively low in its center, where external influences are buffered. Considering linear trends for winds and runoff and surface temperature over the period 1950–2021, we found that northeasterlies increased, runoff decreased, and inshore sea surface temperatures have warmed slowly relative to the adjacent land surface temperature. New insights derive from the use of monthly satellite red-band reflectance and daily 10 km climate reanalysis fields to understand how air–land–sea fluxes modulate the marine environment in the Natal Bight. Full article
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8 pages, 233 KiB  
Article
Adsorbed Chemical Elements of River Runoff of Solids and Their Role in the Transformation of Dissolved Matter Runoff into the Ocean
by Alla V. Savenko and Vitaly S. Savenko
Minerals 2022, 12(4), 445; https://doi.org/10.3390/min12040445 - 4 Apr 2022
Cited by 2 | Viewed by 1879
Abstract
A procedure for experimental modeling of sorption–desorption processes in the mixing zone of river and sea waters, which excludes the determination of the absolute concentrations of adsorbed chemical elements, has been proposed. Based on experimental data, quantitative characteristics of the ion-exchange transformation of [...] Read more.
A procedure for experimental modeling of sorption–desorption processes in the mixing zone of river and sea waters, which excludes the determination of the absolute concentrations of adsorbed chemical elements, has been proposed. Based on experimental data, quantitative characteristics of the ion-exchange transformation of dissolved matter runoff during the penetration of terrigenous material into the marine environment were obtained. The real input of calcium into the ocean as a result of desorption from the solid substances of river runoff increases by 8.3–8.7%, while input of sodium, potassium, and magnesium decreases by 14.0–14.6, 22.2–23.3, and 3.0–3.2% of their dissolved river runoff. For trace elements, sorption–desorption processes lead to an increase in the runoff of dissolved manganese, cobalt, nickel, cadmium, thallium, barium, and ammonium by 98.6–103.5, 20.6–21.6, 3.8–4.0, 15.6–16.5, 4.7–4.9, 20.3–21.3, and 0.8% and to a decrease in the runoff of dissolved lead and cesium by 9.1–9.4 and 2.6–2.8%. Full article
32 pages, 1215 KiB  
Review
The Main Features of Phosphorus Transport in World Rivers
by Vitaly S. Savenko and Alla V. Savenko
Water 2022, 14(1), 16; https://doi.org/10.3390/w14010016 - 22 Dec 2021
Cited by 16 | Viewed by 6628
Abstract
Data on the geochemistry of phosphorus in the continental runoff of dissolved and solid substances were systematized and generalized, with a separate consideration of the processes of runoff transformation in river mouth areas. It has been established that atmospheric deposition, which many authors [...] Read more.
Data on the geochemistry of phosphorus in the continental runoff of dissolved and solid substances were systematized and generalized, with a separate consideration of the processes of runoff transformation in river mouth areas. It has been established that atmospheric deposition, which many authors consider to be an important source of phosphorus in river runoff and not associated with mobilization processes in catchments, actually contains phosphorus from soil-plant recycling. This is confirmed by the fact that the input of phosphorus from the atmosphere into catchments exceeds its removal via water runoff. An analysis of the mass ratio of phosphorus in the adsorbed form and in the form of its own minerals was carried out. It was shown that the maximum mass of adsorbed phosphorus is limited by the solubility of its most stable minerals. The minimum concentrations of dissolved mineral and total phosphorus were observed in the rivers of the Arctic and subarctic belts; the maximum concentrations were confined to the most densely populated temperate zone and the zone of dry tropics and subtropics. In the waters of the primary hydrographic network, the phosphorus concentration exhibited direct relationships with the population density in the catchments and the mineralization of the river water and was closely correlated with the nitrogen content. This strongly suggests that economic activity is one of the main factors in the formation of river phosphorus runoff. The generalization of the authors’ and the literature’s data on the behavior of phosphorus at the river–sea mixing zone made it possible to draw a conclusion about the nonconservative distribution of phosphorus, in most cases associated with biological production and destruction processes. The conservative behavior of phosphorus was observed only in heavily polluted river mouths with abnormally high concentrations of this element. Full article
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15 pages, 11084 KiB  
Review
A Review of Quantifying pCO2 in Inland Waters with a Global Perspective: Challenges and Prospects of Implementing Remote Sensing Technology
by Zhidan Wen, Yingxin Shang, Lili Lyu, Sijia Li, Hui Tao and Kaishan Song
Remote Sens. 2021, 13(23), 4916; https://doi.org/10.3390/rs13234916 - 3 Dec 2021
Cited by 15 | Viewed by 3827
Abstract
The traditional field-based measurements of carbon dioxide (pCO2) for inland waters are a snapshot of the conditions on a particular site, which might not adequately represent the pCO2 variation of the entire lake. However, these field measurements [...] Read more.
The traditional field-based measurements of carbon dioxide (pCO2) for inland waters are a snapshot of the conditions on a particular site, which might not adequately represent the pCO2 variation of the entire lake. However, these field measurements can be used in the pCO2 remote sensing modeling and verification. By focusing on inland waters (including lakes, reservoirs, rivers, and streams), this paper reviews the temporal and spatial variability of pCO2 based on published data. The results indicate the significant daily and seasonal variations in pCO2 in lakes. Rivers and streams contain higher pCO2 than lakes and reservoirs in the same climatic zone, and tropical waters typically exhibit higher pCO2 than temperate, boreal, and arctic waters. Due to the temporal and spatial variations of pCO2, it can differ in different inland water types in the same space-time. The estimation of CO2 fluxes in global inland waters showed large uncertainties with a range of 1.40–3.28 Pg C y−1. This paper also reviews existing remote sensing models/algorithms used for estimating pCO2 in sea and coastal waters and presents some perspectives and challenges of pCO2 estimation in inland waters using remote sensing for future studies. To overcome the uncertainties of pCO2 and CO2 emissions from inland waters at the global scale, more reliable and universal pCO2 remote sensing models/algorithms will be needed for mapping the long-term and large-scale pCO2 variations for inland waters. The development of inverse models based on dissolved biogeochemical processes and the machine learning algorithm based on measurement data might be more applicable over longer periods and across larger spatial scales. In addition, it should be noted that the remote sensing-retrieved pCO2/the CO2 concentration values are the instantaneous values at the satellite transit time. A major technical challenge is in the methodology to transform the retrieved pCO2 values on time scales from instant to days/months, which will need further investigations. Understanding the interrelated control and influence processes closely related to pCO2 in the inland waters (including the biological activities, physical mixing, a thermodynamic process, and the air–water gas exchange) is the key to achieving remote sensing models/algorithms of pCO2 in inland waters. This review should be useful for a general understanding of the role of inland waters in the global carbon cycle. Full article
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19 pages, 8986 KiB  
Article
Detection and Analysis of the Causes of Intensive Harmful Algal Bloom in Kamchatka Based on Satellite Data
by Valery Bondur, Viktor Zamshin, Olga Chvertkova, Ekaterina Matrosova and Vasilisa Khodaeva
J. Mar. Sci. Eng. 2021, 9(10), 1092; https://doi.org/10.3390/jmse9101092 - 7 Oct 2021
Cited by 14 | Viewed by 3681
Abstract
In this paper, the causes of the anomalous harmful algal bloom which occurred in the fall of 2020 in Kamchatka have been detected and analyzed using a long-term time series of heterogeneous satellite and simulated data with respect to the sea surface height [...] Read more.
In this paper, the causes of the anomalous harmful algal bloom which occurred in the fall of 2020 in Kamchatka have been detected and analyzed using a long-term time series of heterogeneous satellite and simulated data with respect to the sea surface height (HYCOM) and temperature (NOAA OISST), chlorophyll-a concentration (MODIS Ocean Color SMI), slick parameters (SENTINEL-1A/B), and suspended matter characteristics (SENTINEL-2A/B, C2RCC algorithm). It has been found that the harmful algal bloom was preceded by temperature anomalies (reaching 6 °C, exceeding the climatic norm by more than three standard deviation intervals) and intensive ocean level variability followed by the generation of vortices, mixing water masses and providing nutrients to the upper photic layer. The harmful algal bloom itself was manifested in an increase in the concentration of chlorophyll-a, its average monthly value for October 2020 (bloom peak) approached 15 mg/m3, exceeding the climatic norm almost four-fold for the region of interest (Avacha Gulf). The zones of accumulation of a large amount of biogenic surfactant films registered in radar satellite imagery correlate well with the local regions of the highest chlorophyll-a concentration. The harmful bloom was influenced by river runoff, which intensively brought mineral and biogenic suspensions into the marine environment (the concentration of total suspended matter within the plume of the Nalycheva River reached 10 mg/m3 and more in 2020), expanding food resources for microalgae. Full article
(This article belongs to the Special Issue Sea Level Fluctuations)
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13 pages, 4680 KiB  
Article
Multi-Decadal Deltaic Land-Surface Changes: Gauging the Vulnerability of a Selection of Mediterranean and Black Sea River Deltas
by Edward J. Anthony, Manon Besset, Florin Zainescu and François Sabatier
J. Mar. Sci. Eng. 2021, 9(5), 512; https://doi.org/10.3390/jmse9050512 - 9 May 2021
Cited by 9 | Viewed by 2876
Abstract
Areal changes over delta surfaces determined by land and water ratios are a promising tool for identifying spatial and temporal changes in deltas that may reveal subsidence and shoreline erosion. Such changes can also provide the basis for more detailed studies on variations [...] Read more.
Areal changes over delta surfaces determined by land and water ratios are a promising tool for identifying spatial and temporal changes in deltas that may reveal subsidence and shoreline erosion. Such changes can also provide the basis for more detailed studies on variations in land-cover and vegetation. Changes in land and water areas over a 35-year period (1984–2019) were determined for a selection of ten river deltas in the Mediterranean (Nile, Rhône, Po, Ebro, Moulouya, Ceyhan-Seyhan, Medjerdja, Ombrone, Arno) and the Black Sea (Danube), with a particular focus on aspects of subsidence and shoreline erosion. With the exception of the Ombrone, Arno, and Moulouya, and to lesser extent the Medjerdja, where notable changes dominate in the coastal zone and are tantamount to net erosion, the spatial pattern is largely dominated by delta-plain changes characterized by increasing areas of water. The pattern reflects a mix of shoreline erosion, land-use and land-cover changes, such as the ecological restoration of wetlands, but also increasing subsidence in these deltas, all of which have been exposed to a declining fluvial sediment supply due to human influence. The use of data on land-water ratios needs to be complemented by more detailed studies devoted to each delta in order to clearly disentangle changes related to land-use, vegetation, and subsidence. It is also important to determine how wetlands are interpreted in such ratios, as these important ecological elements are sensitive to ratio variations. It would also be interesting in future studies to examine how these variations play out over time, notably in deltas where changes have been significant over the period 1984–2019. Full article
(This article belongs to the Special Issue Novel Technologies and Solutions for Coastal Evolution and Management)
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21 pages, 7142 KiB  
Article
CDOM Optical Properties and DOC Content in the Largest Mixing Zones of the Siberian Shelf Seas
by Anastasia N. Drozdova, Andrey A. Nedospasov, Nikolay V. Lobus, Svetlana V. Patsaeva and Sergey A. Shchuka
Remote Sens. 2021, 13(6), 1145; https://doi.org/10.3390/rs13061145 - 17 Mar 2021
Cited by 19 | Viewed by 4845
Abstract
Notable changes in the Arctic ecosystem driven by increased atmospheric temperature and ice cover reduction were observed in the last decades. Ongoing environmental shifts affect freshwater discharge to the Arctic Ocean, and alter Arctic land-ocean fluxes. The monitoring of DOC distribution and CDOM [...] Read more.
Notable changes in the Arctic ecosystem driven by increased atmospheric temperature and ice cover reduction were observed in the last decades. Ongoing environmental shifts affect freshwater discharge to the Arctic Ocean, and alter Arctic land-ocean fluxes. The monitoring of DOC distribution and CDOM optical properties is of great interest both from the point of view of validation of remote sensing models, and for studying organic carbon transformation and dynamics. In this study we report the DOC concentrations and CDOM optical characteristics in the mixing zones of the Ob, Yenisei, Khatanga, Lena, Kolyma, and Indigirka rivers. Water sampling was performed in August–October 2015 and 2017. The DOC was determined by high-temperature combustion, and absorption coefficients and spectroscopic indices were calculated using the seawater absorbance obtained with spectrophotometric measurements. Kara and Laptev mixing zones were characterized by conservative DOC behavior, while the East Siberian sea waters showed nonconservative DOC distribution. Dominant DOM sources are discussed. The absorption coefficient aCDOM (350) in the East Siberian Sea was two-fold lower compared to Kara and Laptev seawaters. For the first time we report the DOC content in the Khatanga River of 802.6 µM based on the DOC in the Khatanga estuary. Full article
(This article belongs to the Special Issue Remote Sensing of the Aquatic Environments)
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14 pages, 4026 KiB  
Article
Analysis of Urban Heat Island (UHI) in Relation to Normalized Difference Vegetation Index (NDVI): A Comparative Study of Delhi and Mumbai
by Aakriti Grover and Ram Babu Singh
Environments 2015, 2(2), 125-138; https://doi.org/10.3390/environments2020125 - 15 Apr 2015
Cited by 221 | Viewed by 26925
Abstract
The formation and occurrence of urban heat island (UHI) is a result of rapid urbanization and associated concretization. Due to intensification of heat combined with high pollution levels, urban areas expose humans to unexpected health risks. In this context, the study aims at [...] Read more.
The formation and occurrence of urban heat island (UHI) is a result of rapid urbanization and associated concretization. Due to intensification of heat combined with high pollution levels, urban areas expose humans to unexpected health risks. In this context, the study aims at comparing the UHI in the two largest metropolitan cities of India, i.e., Delhi and Mumbai. The presence of surface UHI is analyzed using the Landsat 5 TM image of 5 May 2010 for Delhi and the 17 April 2010 image for Mumbai. The validation of the heat island is done in relation to the Normalized Difference Vegetation Index (NDVI) patterns. The study reveals that built-up and fallow lands record high temperatures, whereas the vegetated areas and water bodies exhibit lower temperatures. Delhi, an inland city, possesses mixed land use and the presence of substantial tree cover along roads; the Delhi Ridge forests and River Yamuna cutting across the city have a high influence in moderating the surface temperatures. The temperature reaches a maximum of 35 °C in West Delhi and a minimum of 24 °C in the east at the River Yamuna. Maximum temperature in East Delhi goes to 30 °C, except the border areas. North, Central and south Delhi have low temperatures (28 °C–31 °C), but the peripheral areas have high temperatures (36 °C–37 °C). The UHI is not very prominent in the case of Delhi. This is proven by the correlations of surface temperature with NDVI. South Delhi, New Delhi and areas close to River Yamuna have high NDVI and, therefore, record low temperatures. Mumbai, on the other hand, is a coastal city with lower tree cover than Delhi. The Borivilli National Park (BNP) is in the midst of dense horizontal and vertical growth of buildings. The UHI is much stronger where the heat is trapped that is, the built-up zones. There are four small rivers in Mumbai, which have low carrying capacity. In Mumbai suburban district, the areas adjoining the creeks, sea and the lakes act as heat sinks. The coastal areas in South Mumbai record temperatures of 28 °C–31 °C; the Bandra-Kurla Complex has a high range of temperature i.e., 31 °C–36 °C. The temperature witnessed at Chattrapati Shivaji International Airport is as high as 38 °C. The temperature is nearly 37 °C–38 °C in the Dorai region in the Mumbai suburban district. The BNP has varied vegetation density, and therefore, the temperature ranges from 27 °C–31 °C. Powai Lake, Tulsi Lake and other water bodies record the lowest temperatures (24 °C–26 °C). There exists a strong negative correlation between NDVI and UHI of Mumbai, owing to less coverage of green and vegetation areas. Full article
(This article belongs to the Special Issue Selected Papers from 2014 Global Land Project (GLP) Asia Conference)
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