scholarly journals Terminal motions of Longbasaba Glacier and their mass contributions to proglacial lake volume during 1988–2018

2020 ◽  
Author(s):  
Junfeng Wei ◽  
Shiyin Liu ◽  
Te Zhang ◽  
Xin Wang ◽  
Yong Zhang ◽  
...  
Keyword(s):  
Lake Water ◽  
Local Governments ◽  
Mitigation Measures ◽  
Glacial Lake ◽  
Water Volume ◽  
Landsat Images ◽  
Glacier Surface ◽  
Glacier Shrinkage ◽  
Lake Volume ◽  
Proglacial Lake

Abstract. The interaction between a glacier and its glacial lake plays an increasingly important role in glacier shrinkage and proglacial lake expansion, and it increases the risk of glacial lake outburst floods (GLOFs). Longbasaba Glacier is directly contacted by a moraine-dammed lake with a high outburst risk in the central Himalayas, and has drawn a great deal of attention from scientists and local governments. Based on Landsat images and in-situ measurements, the evolution records of the shrinkage of Longbasaba Glacier and the corresponding expansion of its proglacial lake were determined for 1988–2018, and the mass contributions of glacier shrinkage to the increase in lake water volume were assessed. During the past three decades, Longbasaba Glacier has experienced a continuous and accelerating recession in glacier area and length but accompanied by the decelerating surface lowing and ice flow. Consequently, Longbasaba Lake has expanded significantly at an accelerating rate. The glacier surface lowering played a predominant role in the mass contribution of glacier shrinkage to the increase in lake water volume, while ice avalanches were the main potential trigger for failure of moraine dams and subsequent GLOF events. Due to the areal expansion, decreasing mass contributions from parent glacier shrinkage, and some mitigation measures by local governments to improve the drainage systems, the potential risk of outburst for Longbasaba Lake has continuously decreased during the last decade.

scholarly journals Recent glacier and lake changes in High Mountain Asia and their relation to precipitation changes

2019 ◽  
Vol 13 (11) ◽  
pp. 2977-3005 ◽  
Author(s):  
Désirée Treichler ◽  
Andreas Kääb ◽  
Nadine Salzmann ◽  
Chong-Yu Xu
Keyword(s):  
Shuttle Radar Topography Mission ◽  
Reanalysis Data ◽  
Tien Shan ◽  
Water Volume ◽  
High Mountain ◽  
The Tibetan Plateau ◽  
Glacier Surface ◽  
Spatially Resolved ◽  
Lake Volume ◽  
Precipitation Increase

Abstract. We present an updated, spatially resolved estimate of 2003–2008 glacier surface elevation changes for the entire region of High Mountain Asia (HMA) from ICESat laser altimetry data. The results reveal a diverse pattern that is caused by spatially greatly varying glacier sensitivity, in particular to precipitation availability and changes. We introduce a spatially resolved zonation where ICESat samples are grouped into units of similar glacier behaviour, glacier type and topographic settings. In several regions, our new zonation reveals local differences and anomalies that have not been described previously. Glaciers in the Eastern Pamirs, Kunlun Shan and central TP were thickening by 0.1–0.7 m a−1, and the thickening anomaly has a crisp boundary in the Eastern Pamirs that continues just north of the central Karakoram. Glaciers in the south and east of the TP were thinning, with increasing rates towards southeast. We attribute the glacier thickening signal to a stepwise increase in precipitation around ∼1997–2000 on the Tibetan Plateau (TP). The precipitation change is reflected by growth of endorheic lakes in particular in the northern and eastern TP. We estimate lake volume changes through a combination of repeat lake extents from Landsat data and shoreline elevations from ICESat and the Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) for over 1300 lakes. The rise in water volume contained in the lakes corresponds to 4–25 mm a−1, when distributed over entire catchments, for the areas where we see glacier thickening. The precipitation increase is also visible in sparse in situ measurements and MERRA-2 climate reanalysis data but less visible in ERA-Interim reanalysis data. Taking into account evaporation loss, the difference between average annual precipitation during the 1990s and 2000s suggested by these datasets is 34–100 mm a−1, depending on region, which can fully explain both lake growth and glacier thickening (Kunlun Shan) or glacier geometry changes such as thinning tongues while upper glacier areas were thickening or stable (eastern TP). The precipitation increase reflected in these glacier changes possibly extended to the northern slopes of the Tarim Basin, where glaciers were nearly in balance in 2003–2008. Along the entire Himalaya, glaciers on the first orographic ridge, which are exposed to abundant precipitation, were thinning less than glaciers in the dryer climate of the inner ranges. Thinning rates in the Tien Shan vary spatially but are rather stronger than in other parts of HMA.

scholarly journals Longbasaba Glacier recession and contribution to its proglacial lake volume between 1988 and 2018

2021 ◽  
pp. 1-12
Author(s):  
Junfeng Wei ◽  
Shiyin Liu ◽  
Xin Wang ◽  
Yong Zhang ◽  
Zongli Jiang ◽  
...  
Keyword(s):  
Mass Loss ◽  
Total Mass ◽  
Water Volume ◽  
Total Mass Loss ◽  
Lake Volume ◽  
Glacier Recession ◽  
Proglacial Lakes ◽  
Proglacial Lake ◽  
Near Future ◽  
The Himalaya

Abstract During the last few decades, the lake-terminating glaciers in the Himalaya have receded faster than the land-terminating glaciers as proglacial lakes have exacerbated the mass loss of their host glaciers. Monitoring the impacts of glacier recession and dynamics on lake extent and water volume provides an approach to assess the mass interplay between glaciers and proglacial lakes. We describe the recession of Longbasaba Glacier and estimate the mass wastage and its contribution to the water volume of its proglacial lake. The results show that the glacier area has decreased by 3% during 1988–2018, with a more variable recession prior to 2008 than in the last decade. Longbasaba Lake has expanded by 164% in area and 237% in water volume, primarily as a result of meltwater inflow produced from surface lowering of the glacier. Over the periods 1988–2000 and 2000–18, the mass loss contributed by glacier thinning has decreased from 81 to 61% of the total mass loss, accompanied by a nearly doubled contribution from terminus retreat. With the current rate of retreat, Longbasaba glacier is expected to terminate in its proglacial lake for another four decades. The hazard risk of this lake is expected to continue to increase in the near future because of the projected continued glacier mass loss and related lake expansion.

scholarly journals Hazard assessment of glacial lake outburst floods from Kyagar glacier, Karakoram mountains, China

2014 ◽  
Vol 55 (66) ◽  
pp. 34-44 ◽  
Author(s):  
Christoph Haemmig ◽  
Matthias Huss ◽  
Hansrudolf Keusen ◽  
Josef Hess ◽  
Urs Wegmüller ◽  
...  
Keyword(s):  
Warning System ◽  
Flow Speed ◽  
Glacial Lake ◽  
Glacier Surface ◽  
Ice Flow ◽  
Surface Mass ◽  
Lake Volume ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Karakoram Mountains

AbstractKyagar glacier is located in the Chinese Karakoram mountains. The glacier tongue entirely blocks the riverbed in the upper Shaksgam valley and impounds a glacial lake, which was the source of several violent and disastrous glacial lake outburst floods (GLOFs). A GLOF early warning system was implemented between 2011 and 2013. We present an integrative analysis of the hazard potential of Kyagar lake, taking into account the ice flow dynamics of Kyagar glacier as well as the recent surface mass-balance response to climate change. Comparison of two high-resolution digital elevation models (DEMs) for the ice dam shows surface lowering rates of >5ma– 1 between 2002 and 2011, leading to a significant reduction in the maximum potential lake volume. However, two DEMs covering the entire glacier for the period 2000–10 indicate mass gains in its central part, and flow speed measurements show an acceleration in this region. This pattern of local ice-thickness changes combined with varying ice flow velocities is typical for surge-type glaciers. The velocity of the glacier surface and of the ice dam between 2011 and 2012 are analyzed at high temporal and spatial resolution, based on feature tracking of synthetic aperture radar (SAR) images.

scholarly journals Dynamics of Lower-Barun Glacier and Glacial Lake and its GLOF Susceptibility Using Geospatial Analysis and Modelling

Jalawaayu ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 57-77
Author(s):  
Nabin Gurung ◽  
Sudeep Thakuri ◽  
Raju Chauhan ◽  
Narayan Prasad Ghimire ◽  
Motilal Ghimire
Keyword(s):  
Failure Time ◽  
Peak Discharge ◽  
Mitigation Measures ◽  
Glacial Lake ◽  
Water Volume ◽  
Glacial Lakes ◽  
Water Index ◽  
Outburst Floods ◽  
Normalized Difference Water Index ◽  
Multi Temporal

Shrinkage of some of the glaciers has direct impacts on the formation and expansion of glacial lakes. Sudden glacial lake outburst floods (GLOFs) are a major threat to lives and livelihoods downstream as they can cause catastrophic damage. In this study, we present the dynamics of the Lower-Barun glacier and glacial lakes and their GLOF susceptibility. We used multi temporal Landsat and Sentinel satellite imagery and extracted the lake outlines using the Normalized Difference Water Index (NDWI) with manual post-correction while the glacier outline was digitized manually. Multi-criteria decision-based method was used to assess the GLOF susceptibility. For the estimation of peak discharge and failure time, an empirical model developed by Froelich (1995) was used. The surface area of the Lower-Barun glacial lake was increased by 86% in the last 40 yrs (from 1979 to 2018), with a mean increase of 0.0432 km2/yr. The shrinkage in the glacier area is around 0.49 km2/yr and has shrunk by 8% in the last four decades. The retreat of the Lower-Barun glacier was 0.20% per year in the last four decades. The susceptibility index was 0.94, which suggests that the lake is very highly susceptible to the GLOF. The peak discharge of 5768 m3/s is produced when the breach depth is 20 m and the entire water volume is released. Likewise, in the case of 15 m breach depth, the peak discharge of 4038 m3/s is formed. Breach depth scenario of 10 m, peak discharge of 2442 m3/s is produced and in case of breach depth of 5 m produces the peak discharge of 1034 m3/s. If GLOF occurs, it can exert disastrous impacts on the livelihood and infrastructure in the downstream. So, it is necessary to examine such lakes regularly and mitigation measures to lower the GLOF susceptibility should be emphasized.

scholarly journals Lake water volume calculation using time series LANDSAT satellite data: a geospatial analysis of Deepor Beel Lake, Guwahati

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ishita Afreen Ahmed ◽  
Shahfahad Shahfahad ◽  
Mirza Razi Imam Baig ◽  
Swapan Talukdar ◽  
Md Sarfaraz Asgher ◽  
...  
Keyword(s):  
Time Series ◽  
Lake Water ◽  
Water Surface ◽  
Water Resource Management ◽  
Storage Capacity ◽  
Water Volume ◽  
Landsat Images ◽  
Rapid Urbanization ◽  
Volume Calculation ◽  
Content Type

PurposeDeepor Beel is one of the Ramsar Site and a wetland of great biodiversity, situated in the south-western part of Guwahati, Assam. With urban development at its forefront city of Guwahati, Deepor Beel is under constant threat. The study aims to calculate the lake water volume from the water surface area and the underwater terrain data using a triangulated irregular network (TIN) volume model.Design/methodology/approachThe lake water surface boundaries for each year were combined with field-observed water level data to generate a description of the underwater terrain. Time series LANDSAT images of 2001, 2011 and 2019 were used to extract the modified normalized difference water index (MNDWI) in GIS domain.FindingsThe MNDWI was 0.462 in 2001 which reduced to 0.240 in 2019. This shows that the lake water storage capacity shrank in the last 2 decades. This leads to a major problem, i.e. the storage capacity of the lake has been declining gradually from 20.95 million m3 in 2001 to 16.73 million m3 in 2011 and further declined to 15.35 million m3 in 2019. The fast decline in lake water volume is a serious concern in the age of rapid urbanization of big cities like Guwahati.Originality/valueNone of the studies have been done previously to analyze the decline in the volume of Deepor Beel lake. Therefore, this study will provide useful insights in the water resource management and the conservation of Deepor Beel lake.

scholarly journals Quantifying the impacts of human water use and climate variations on recent drying of Lake Urmia basin: the value of different sets of spaceborne and in-situ data for calibrating a hydrological model

2018 ◽  
Author(s):  
Seyed-Mohammad Hosseini-Moghari ◽  
Shahab Araghinejad ◽  
Mohammad J. Tourian ◽  
Kumars Ebrahimi ◽  
Petra Döll
Keyword(s):  
Time Series ◽  
Water Use ◽  
Lake Water ◽  
Water Storage ◽  
Water Volume ◽  
Total Water ◽  
Lake Urmia ◽  
Groundwater Levels ◽  
Lake Volume

Abstract. During the last decades, the endorheic Lake Urmia basin in northwestern Iran has suffered from decreased precipitation, groundwater levels and a very strong reduction in the volume and more recently also in the extent of Lake Urmia. Human water use has exacerbated the desiccating impact of climatic variations. This study quantifies the contribution of human water use to the reduction of inflow into Lake Urmia, to the loss of lake water volume and to the loss of groundwater and total water storage in the entire Lake Urmia basin during 2003–2013. To this end, the WaterGAP Global Hydrology Model (WGHM) was manually calibrated specifically for the basin against multiple in-situ and spaceborne data, and the best-performing calibration variant was run with or without taking into account water use. Observation data encompass remote-sensing based time series of annual irrigated area in the basin from MODIS, monthly total water storage anomaly (TWSA) from GRACE satellites and monthly lake volume. In-situ observations include time series of annual inflow into the lake and basin averages of groundwater level variations based on 284 wells. In addition, local estimates of sectoral water withdrawals in 2009 and return flow fractions were utilized. Four calibration variants were set up in which the number of considered observation types was increased in a stepwise fashion. The best fit to each and all observations is achieved if the maximum amount of observations is used for calibration. Calibration against GRACE TWSA improves simulated inflow into Lake Urmia but still overestimates it by 90 %; it results in an overestimation of lake volume loss, underestimation of groundwater loss and a shifted seasonality of groundwater storage. Lake and groundwater dynamics can only be simulated well if calibration against groundwater levels leads to adjusting the fractions of human water use from groundwater and surface water. According to our study, human water use was the reason for 50 % of the total basin water loss of about 10 km3 during 2003–2013, for 40 % of the Lake Urmia water loss of about 8 km3 and for up to 90 % of the groundwater loss. Lake inflow was 40 % less than it would have been without human water use. We found that even without human water use, Lake Urmia would not have recovered from the significant loss of lake water volume caused by the drought year 2008. These findings may serve to support water management in the basin and more specifically Lake Urmia restoration plans.

GLACIAL LAKE LOW: A PREVIOUSLY UNIDENTIFIED PROGLACIAL LAKE IN WESTERN LABRADOR

2020 ◽  
Author(s):  
Roger Paulen ◽  
◽  
Jessey Rice ◽  
Martin Ross ◽  
Olav B. Lian
Keyword(s):  
Glacial Lake ◽  
Proglacial Lake

Climate Change Surge: Implementing Stringent Mitigation and Adaptation Strategies in South Africa

2010 ◽  
Vol 54 (2) ◽  
pp. 159-183
Author(s):  
Kola Odeku ◽  
Edson Meyer
Keyword(s):  
Climate Change ◽  
South African ◽  
Local Governments ◽  
State Of The Art ◽  
Adaptation Strategies ◽  
Mitigation Measures ◽  
African Government ◽  
Mitigation And Adaptation ◽  
Vulnerability To Climate Change ◽  
Mitigation And Adaptation Strategies

AbstractThis article examines how the South African government, realizing the country's vulnerability to climate change, deemed it necessary to strengthen adaptation and mitigation measures and put in place legal and institutional frameworks to ensure implementation and compliance. Government must take responsibility for industry's inaction by implementing policies on climate change and, more importantly, through a visible change in government policy to hold industry accountable. The stringent policies and strategies being put in place are reducing vulnerability and also enhancing a broad spectrum of capacity in responding to environmental, climatic, resource and economic perturbations. The article further reviews state of the art methods and tools available to strengthen mitigation and adaptation strategies and measures in the areas of the existing frameworks regarding climate change. It also considers various measures by Eskom in particular, and strategies embarked upon by South Africa's national and local governments to reduce greenhouse gas emissions.

scholarly journals Causes of the extensive hypoxia in the Gulf of Riga in 2018

2021 ◽  
Author(s):  
Stella-Theresa Stoicescu ◽  
Jaan Laanemets ◽  
Taavi Liblik ◽  
Māris Skudra ◽  
Oliver Samlas ◽  
...  
Keyword(s):  
Bottom Layer ◽  
Oxygen Depletion ◽  
Phosphorus Release ◽  
Meteorological Conditions ◽  
Mitigation Measures ◽  
Sediment Surface ◽  
Water Volume ◽  
Gulf Of Riga ◽  
Baltic Proper ◽  
The Baltic

Abstract. The Gulf of Riga is a relatively shallow bay connected to the deeper central Baltic Sea (Baltic Proper) via straits with sills. The decrease in the near-bottom oxygen levels from spring to autumn is a common feature in the gulf, but in 2018, hypoxia was exceptional. We analyzed temperature, salinity, oxygen, and nutrient data collected in 2018 and historical data available from environmental databases. Forcing data from the study year were compared with their long-term means and variability. The year 2018 was exceptional due to occasionally dominating north-easterly winds supporting the inflow of saltier waters from the Baltic Proper and meteorological conditions causing fast development of thermal stratification in spring. Existing stratification hindered vertical transport between the near-bottom layer (NBL) and the water layers above it. The estimated oxygen consumption rate at the sediment surface in spring-summer 2018 was about 1.7 mmol O2 m−2 h−1 that exceeded the oxygen input to the NBL due to advection and mixing. We suggest that the observed pronounced oxygen depletion was magnified by the prolonged stratified season and haline stratification in the deep layer that maintained a decreased water volume between the seabed and the pycnocline. The observed increase in phosphate concentrations in the NBL in summer 2018 suggests a significant sediment phosphorus release in hypoxic conditions counteracting the mitigation measures to combat eutrophication. We conclude, if similar meteorological conditions as in 2018 could occur more frequently in the future, such extensive hypoxia would be more common in the Gulf of Riga and other coastal basins with similar morphology and human-induced elevated input of nutrients.

scholarly journals "Hurricane" Sandy

2018 ◽  
Vol 5 (2) ◽  
pp. 157-192
Author(s):  
Cheryl L. Pollak
Keyword(s):  
United States ◽  
New York ◽  
Local Governments ◽  
The United States ◽  
Hurricane Sandy ◽  
Small Business Administration ◽  
Mitigation Measures ◽  
District Court ◽  
Flood Insurance ◽  
Recent Experience

On the evening of October 29, 2012, “Hurricane” Sandy made land- fall on the New York coastline, battering the land with strong winds, torrential rain, and record-breaking storm surges. Homes and commercial structures were destroyed; roads and tunnels were flooded; and more than 23,000 people sought refuge in temporary shelters, with many others facing weeks without power and electricity. At the time, Sandy was heralded as one of the costliest hurricanes in the his- tory of the United States; the second costliest hurricane only to Katrina, which hit New Orleans in 2005. Unfortunately, recent experience with Hurricanes Florence, Maria, Harvey, and Irma suggest that this pattern of devastating superstorms may become the new norm as climate change produces more extreme and unpredictable weather events. In Sandy’s aftermath, as individuals returned to their homes, or what remained of them, and communities began to rebuild, the true cost of the storm became apparent. A year after the storm, the Federal Emergency Management Agency (“FEMA”) estimated that over $1.4 billion in assistance was provided to 182,000 survivors of the dis- aster; another $3.2 billion was provided to state and local governments for debris removal, infrastructure repair, and emergency protective measures. More than $2.4 billion was provided to individuals and businesses in the form of low-interest loans through the Small Business Administration (“SBA”), and millions more were spent on grants de- signed to implement mitigation measures in the future and to provide unemployment assistance to survivors. Before the storm, homeowners paid premiums for flood insurance provided through the National Flood Insurance Program (“NFIP”), and for homeowner’s insurance provided by dozens of private insurers. In the months following the storm, they began to file claims for assistance in rebuilding their homes. While many such claims were re- solved successfully, many homeowners were unhappy with the settlement amounts offered by their insurance carriers and felt compelled to file lawsuits in the surrounding state and federal courts. Many of those lawsuits were filed in the United States District Court for the Eastern District of New York (“EDNY”). This case study describes the EDNY’s specifically crafted, unique approach to handling the mass litigation that ensued from Sandy’s devastation, documents some of the problems that the Court faced during that mass litigation, and describes some of the lessons learned from the Court’s experience.

Sign in / Sign up

Export Citation Format

Share Document