scholarly journals Glacier changes between 1971 and 2016 in the Jankar Chhu Watershed, Lahaul Himalaya, India

2018 ◽  
Vol 65 (249) ◽  
pp. 13-28 ◽  
Author(s):  
SURESH DAS ◽  
MILAP CHAND SHARMA
Keyword(s):  
Cloud Cover ◽  
Thematic Mapper ◽  
Landsat Thematic Mapper ◽  
Field Observations ◽  
Glacier Area ◽  
Ablation Zone ◽  
Change Analysis ◽  
Recession Rate ◽  
Glacier Changes ◽  
Sentinel 2A

ABSTRACTGlacier changes in the Jankar Chhu Watershed (JCW) of Chandrabhaga (Chenab) basin, Lahaul Himalaya were worked out based on Corona and Sentinel 2A images between 1971 and 2016. The JCW consists of 153 glaciers (>0.02 km2) with a total area of 185.6 ± 3.8 km2that include 82 glaciers with debris-covered ablation zone, comprising 10.9% of the total glacierized area as in 2016. Change analysis based on Corona (1971), Landsat (2000) and Sentinel 2A (2016) was restricted to 127 glaciers owing to the presence of cloud cover on 26 glaciers in 1971. A subset of glaciers was also mapped using Landsat Thematic Mapper (TM; 1989) image. The total glacier area decreased by 14.7 ± 4.3 km2(0.3 ± 0.1 km2a−¹). The number of glaciers in the JCW increased by four between 1971 and 2016 due to fragmentation. More recently (2000–16), recession rate has increased. Clean-ice area decreased by 21.8 ± 3.8 km2(0.5 ± 0.1 km2a−¹) while debris-covered ice increased by 7.2 ± 0.4 km2(0.2 ± 0.01 km2a−¹). Field observations of select glaciers also support derived recession trend in the JCW. Retreat rates in the JCW have been observed to be much lower than previously reported.

scholarly journals Glacier Changes in the Chhombo Chhu Watershed of Tista basin between 1975 and 2018, Sikkim Himalaya, India

2021 ◽  
Author(s):  
Arindam Chowdhury ◽  
Milap Chand Sharma ◽  
Sunil Kumar De ◽  
Manasi Debnath
Keyword(s):  
Large Population ◽  
Eastern Himalaya ◽  
Glacier Area ◽  
Change Analysis ◽  
Sikkim Himalaya ◽  
Mountain Communities ◽  
Area Loss ◽  
Landsat 7 ◽  
Landsat 5 Tm ◽  
Sentinel 2A

Abstract. Glaciers of the Tista basin represent an important water resource for mountain communities and large population downstream. The present article attempts to assess the observable changes in the glacier area in the Chhombo Chhu Watershed (CCW) of Tista basin, Sikkim Himalaya. The CCW consists of 74 glaciers (>0.02 km2) with a mean glacier size of 0.61 km2. The change of such glacier outlines obtained from the declassified hexagon KH-9 (1975), Landsat 5 TM (1989), Landsat 7 ETM+ (2000), Landsat 5 TM (2010), and Sentinel 2A (2018). The total glacier area in 1975 was 62.6 ±0.7 km2; by 2018, the area had decreased to 44.8 ±1.5 km2, an area loss of 17.9 ± 1.7 km2 (0.42 ± 0.04 km2 a−1). Debris free glaciers exhibit more area loss by 11.8 ± 1.2 km2 (0.27 ± 0.03  km2 a−1) followed by partially debris-covered (5.0 ± 0.4 km2 or 0.12 ± 0.01 km2 a−1) and maximum debris-covered (1.0 ± 0.1 km2 or −0.02 ± 0.002 km2 a−1) glaciers. The quantum of glacier area loss in the CCW of Sikkim Himalaya took its pace during 2000–2010 (0.62 ± 0.5 km2 a−1) and 2010–2018 (0.77 ± 0.6 km2 a−1) timeframes. Field investigations of selected glaciers and climatic records also support the trend in glacier recession in the CCW due to a significant increase in temperature trend and more or less static precipitation since 1995. Glacier retreat rates in the CCW were almost similar to the Changme Khangpu basin and other selected glaciers in Sikkim Himalaya. This glacier inventory and area change analysis will provide valuable information to the glaciological and hydrological community to model and plan the water resources in the Sikkim state of Eastern Himalaya. The dataset is now available from the Zenodo web portal: http://doi.org/10.5281/zenodo.4457183 (Chowdhury et al., 2021).

scholarly journals Glacier changes in the Chhombo Chhu Watershed of the Tista basin between 1975 and 2018, the Sikkim Himalaya, India

2021 ◽  
Vol 13 (6) ◽  
pp. 2923-2944
Author(s):  
Arindam Chowdhury ◽  
Milap Chand Sharma ◽  
Sunil Kumar De ◽  
Manasi Debnath
Keyword(s):  
Large Population ◽  
Water Source ◽  
Thematic Mapper ◽  
Glacier Area ◽  
Sikkim Himalaya ◽  
Mountain Communities ◽  
Area Loss ◽  
Field Investigations ◽  
Landsat 7 ◽  
Sentinel 2A

Abstract. Glaciers of the Tista basin represent an important water source for mountain communities and a large population downstream. The article presents observable changes in the Chhombo Chhu Watershed (CCW) glacier area of the Tista basin, the Sikkim Himalaya. The CCW contains 74 glaciers (> 0.02 km2) with a mean glacier size of 0.61 km2. We determined changes in glaciers from the declassified Hexagon Keyhole-9 (KH-9) (1975), Landsat 5 Thematic Mapper (TM) (1989), Landsat 7 Enhanced Thematic Mapper Plus (ETM+) (2000), Landsat 5 TM (2010), and Sentinel-2A (2018) images. The total glacier area in 1975 was 62.6 ± 0.7 km2; and by 2018, the area had decreased to 44.8 ± 1.5 km2, an area loss of 17.9 ± 1.7 km2 (0.42 ± 0.04 km2 a−1). Clean glaciers exhibited more area loss of 11.8 ± 1.2 km2 (0.27 ± 0.03 km2 a−1) than partially debris-covered and maximally debris-covered glaciers. The area loss is 5.0 ± 0.4 km2 (0.12 ± 0.01 km2 a−1) for partially covered glaciers and 1.0 ± 0.1 km2 (−0.02 ± 0.002 km2 a−1) for maximally covered glaciers. The glacier area loss in the CCW of the Sikkim Himalaya is 0.62 ± 0.5 km2 a−1 during 2000–2010, and it is 0.77 ± 0.6 km2 a−1 during 2010–2018. Field investigations of selected glaciers and climatic records also support the glacier recession in the CCW due to a significant increase in temperature (0.25 ∘C a−1) and more or less static precipitation since 1995. The dataset is now available from the Zenodo web portal: https://doi.org/10.5281/zenodo.4457183 (Chowdhury et al., 2021).

scholarly journals Glacier Changes and Their Linkage to the Climate-Topographic Context in the Borohoro Mountains, Tian Shan 1977–2018

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1502
Author(s):  
Yanan Li
Keyword(s):  
Climatic Factors ◽  
Warming Trend ◽  
Shuttle Radar Topography Mission ◽  
Surface Elevation ◽  
Glacier Area ◽  
Glacier Changes ◽  
Sentinel 2A ◽  
Essential Knowledge ◽  
Correlated Parameters ◽  
Tian Shan

Against the backdrop of climate change and socio-ecological sustainability, studying glacier changes provides essential knowledge to the basic water needs and security for regions and populations under such threats, such as Central Asia. Little attention has focused on glaciers in the northern periphery of the Chinese Tian Shan. This study aims to map a recent glacier inventory and examine the glacier area shrinkage and surface elevation change for the central massif of the Borohoro Mountains in the past 41 years. Using declassified Hexagon images (1977), Landsat 5 TM (1994 and 2007), Sentinel 2A (2018) and altimetry data from the Ice, Cloud and Land Elevation Satellite (ICESat) over 2003–2009 with the 30-m Shuttle Radar Topography Mission (SRTM) digital elevation model, multi-temporal glacier fluctuations and the influence of topographic and climatic factors were investigated. Results show that the glacier area decreased from 287.5 ± 8.2 km2 in 1977 to 215.8 ± 4.1 km2 in 2018, at a rate of 0.61 ± 0.01% year−1. Glacier disintegration has led to a gradual increase in the number of glaciers and reached 224 glaciers in 2018. The shrinkage was at the highest rate during the 1994–2007 period and the smallest during 1977–1994. Glacier size, hypsometry, and median, maximum, and range of elevation are the most significantly correlated parameters with the relative area change. The surface elevation changes from two of the largest glaciers revealed a stronger thinning on the southern slope compared to the northern slope. These observations of glacier loss are primarily driven by the marked warming trend since the 1970s and confirmed with the overall pattern of glacier retreat in the Tian Shan from previous studies.

scholarly journals Inventory of Glaciers in the Shaksgam Valley of the Chinese Karakoram Mountains, 1970–2014

2018 ◽  
Vol 10 (8) ◽  
pp. 1166 ◽  
Author(s):  
Haireti Alifu ◽  
Yukiko Hirabayashi ◽  
Brian Johnson ◽  
Jean-Francois Vuillaume ◽  
Akihiko Kondoh ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Thematic Mapper ◽  
Western China ◽  
Glacier Area ◽  
Glacier Inventory ◽  
Local Climate ◽  
Glacier Terminus ◽  
Glacier Changes ◽  
Multi Temporal ◽  
Karakoram Mountains

The Shaksgam Valley, located on the north side of the Karakoram Mountains of western China, is situated in the transition zone between the Indian monsoon system and dry arid climate zones. Previous studies have reported abnormal behaviors of the glaciers in this region compared to the global trend of glacier retreat, so the region is of special interest for glacier-climatological studies. For this purpose, long-term monitoring of glaciers in this region is necessary to obtain a better understanding of the relationships between glacier changes and local climate variations. However, accurate historical and up-to-date glacier inventory data for the region are currently unavailable. For this reason, this study conducted glacier inventories for the years 1970, 1980, 1990, 2000 and 2014 (i.e., a ~10-year interval) using multi-temporal remote sensing imagery. The remote sensing data used included Corona KH-4A/B (1965–1971), Hexagon KH-9 (1980), Landsat Thematic Mapper (TM) (1990/1993), Landsat Enhanced Thematic Mapper Plus (ETM+) (2000/2001), and Landsat Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) (2014/2015) multispectral satellite images, as well as digital elevation models (DEMs) from the Shuttle Radar Topography Mission (SRTM), DEMs generated from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images (2005–2014), and Advanced Land Observing Satellite (ALOS) World 3D 30 m mesh (AW3D30). In the year 2014, a total of 173 glaciers (including 121 debris-free glaciers) (>0.5 km2), covering an area of 1478 ± 34 km2 (area of debris-free glaciers: 295 ± 7 km2) were mapped. The multi-temporal glacier inventory results indicated that total glacier area change between 1970–2014 was not significant. However, individual glacier changes showed significant variability. Comparisons of the changes in glacier terminus position indicated that 55 (32 debris-covered) glaciers experienced significant advances (~40–1400 m) between 1970–2014, and 74 (32 debris-covered) glaciers experienced significant advances (~40–1400 m) during the most recent period (2000–2014). Notably, small glaciers showed higher sensitivity to climate changes, and the glaciers located in the western part of the study site were exhibiting glacier area expansion compared to other parts of the Shaksgam Valley. Finally, regression analyses indicated that topographic parameters were not the main driver of glacier changes. On the contrary, local climate variability could explain the complex behavior of glaciers in this region.

Assessing the susceptibility of semiarid rangelands to wildfires using Terra MODIS and Landsat Thematic Mapper data

2011 ◽  
Vol 20 (5) ◽  
pp. 690 ◽  
Author(s):  
Fang Chen ◽  
Keith T. Weber ◽  
Jamey Anderson ◽  
Bhushan Gokhal
Keyword(s):  
Vegetation Change ◽  
Vegetation Index ◽  
Spatial Scales ◽  
Late Summer ◽  
Thematic Mapper ◽  
Fuel Load ◽  
Landsat Thematic Mapper ◽  
Change Analysis ◽  
Active Growth ◽  
Normalised Difference Vegetation Index

In order to monitor wildfires at broad spatial scales and with frequent periodicity, satellite remote sensing techniques have been used in many studies. Rangeland susceptibility to wildfires closely relates to accumulated fuel load. The normalised difference vegetation index (NDVI) and fraction of photosynthetically active radiation (fPAR) are key variables used by many ecological models to estimate biomass and vegetation productivity. Subsequently, both NDVI and fPAR data have become an indirect means of deriving fuel load information. For these reasons, NDVI and fPAR, derived from the Moderate Resolution Imaging Spectroradiometer on-board Terra and Landsat Thematic Mapper imagery, were used to represent prefire vegetation changes in fuel load preceding the Millennial and Crystal Fires of 2000 and 2006 in the rangelands of south-east Idaho respectively. NDVI and fPAR change maps were calculated between active growth and late-summer senescence periods and compared with precipitation, temperature, forage biomass and percentage ground cover data. The results indicate that NDVI and fPAR value changes 2 years before the fire were greater than those 1 year before fire as an abundance of grasses existed 2 years before each wildfire based on field forage biomass sampling. NDVI and fPAR have direct implication for the assessment of prefire vegetation change. Therefore, rangeland susceptibility to wildfire may be estimated using NDVI and fPAR change analysis. Furthermore, fPAR change data may be included as an input source for early fire warning models, and may increase the accuracy and efficiency of fire and fuel load management in semiarid rangelands.

scholarly journals Glacier changes over the past 144 years at Alexandra Fiord, Ellesmere Island, Canada

2021 ◽  
pp. 1-12
Author(s):  
Allison N. Curley ◽  
William H. Kochtitzky ◽  
Benjamin R. Edwards ◽  
Luke Copland
Keyword(s):  
Average Rate ◽  
Ellesmere Island ◽  
Surface Elevation ◽  
Aerial Photographs ◽  
Field Observations ◽  
Glacier Area ◽  
The Past ◽  
Rates Of Change ◽  
Glacier Changes ◽  
The Mean

Abstract In this study, we use aerial photographs, satellite imagery and field observations to quantify changes in the area, terminus length, snowline elevation and surface elevation of eight glaciers in the Alexandra Fiord region, eastern Ellesmere Island, between 1959 and 2019. Comparisons to written and pictorial descriptions from the British Arctic Expedition extend the record of change in terminus position and surface elevation to 1875 for Twin Glacier. Glacier area at Alexandra Fiord decreased by a total of 15.77 ± 0.65 km2 (11.77 ± 0.49%) between 1959 and 2019, the mean end of summer snowline increased in elevation by 360 ± 84 m (8 ± 2 m a−1) between 1974 and 2019, and the glaciers thinned at an average rate of 0.60 ± 0.06 m a−1 between 2001 and 2018. Annual rates of terminus retreat were ~3–5 times higher over the period 1974–2019 compared to 1875–1974, and rates of thinning were ~2–3 times higher over 2001–18 compared to 1875–2001. Our results are consistent with rates of change determined for other glaciers of similar size on Ellesmere Island, and with accelerated rates of ice loss coincident with regional increases in air temperature of ~1.5°C since the early 1980s.

scholarly journals Discrimination of Cabbage Fields for Detecting Clubroot Disease Damage Using Landsat Thematic Mapper Data.

1992 ◽  
Vol 61 (3) ◽  
pp. 527-535 ◽  
Author(s):  
Yoichi TORIGOE ◽  
Tetsuro AMANO ◽  
Kei OGAWA ◽  
Michikazu FUKUHARA
Keyword(s):  
Thematic Mapper ◽  
Landsat Thematic Mapper ◽  
Clubroot Disease ◽  
Thematic Mapper Data ◽  
Disease Damage
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