Kargel

Project Summary

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Development and climate change in High Mountain Asia (HMA) are affecting natural hazards. HMA is vulnerable due to the exposure of large populations and because of high seismic and Earth surface process activity. We will explore links between mountain hazards and glaciers, snowfields, glacial lakes, and unstable mountain slopes and rock debris in glacierized Nepal, Bhutan, and adjoining China- a HMA region of abundant glacial lakes, and floods in the Koshi and Gandaki basins (Nepal) to 200 km downstream. We will investigate over the satellite era (since Landsat 5) the mass movement environment of glacial lakes, lakes’ effects on glacier dynamics, and timescales from glacier lake inception, through growth, to glacier lake outburst floods (GLOFs); compare GLOFs with other mountain flood types: triggers, timescales, peak discharges, and downstream reach. Tasks: (1) Multipectral image analysis to map the sizes/distribution of Himalayan glacial lakes; and to assess the mass wasting environment near glacial lakes—three snapshots (ca. 1987, ca. 2001, ca. 2015) of every lake >10 hectares (roughly >330 m diameter) in any snapshot; develop a seasonally resolved time series of ~30 selected glacial lakes and environments (~100 scenes per lake), nearby snow/ice cover, and selected downstream river inundation areas; map/quantify mass movements near selected glacial lakes; understand annual fluctuations and multidecadal trends of lakes from empirical, climatic, and thermodynamic standpoints; understand mass movement environment and flood discharges using published climate data and models, available hydrographic data, and seasonally resolved time series; assess decadal changes in each selected lake’s damming, glacier mass balance, and moraines using WorldView DEM snapshots. (2) Develop analytical modules for the “Glacier Melt Toolbox” (Glacier Lake Accelerated Melting, GLAM) to quantify heating within glacial lakes and lake effects on glacier mass balance. (a) Analytical module. (b) Radiative transfer module. (3) Field validation at Imja Lake and release of GLAM to the Glacial Melt Toolbox. (4) Interpret results and semi-quantitatively project the development over the next 30 years of high mountain hazards. Use published climate models, available hydrographic data, our time series of floods, mass movement processes, lake growth. Applications focus: mountain village safety and hydroelectric power (present, in construction, planned, and possible). RS data: ASTER (VNIR, SWIR, TIR, GDEM2); EO-1 ALI; Landsats 5, 7, 8; WorldView imagery and DEMs; newly available 8-m SRTM DEM. Field data: Glacial lake bathymetry (echsounding); side scan sonar images of glacier calving front and moraines; lake vertical profiles of temperature, salinity, turbidity and light levels; field photography. GIS datasets on residences, infrastructure, and agriculture. Analytical: Fuzzy C Means subpixel unsupervised soft classifications, and standard NDVI, NDSI, NDWI supervised thresholded indices and other hard classifications (with manual tweaking) of lakes, snow, landslides, etc. COSI-Corr glacier flow speed. DEM differencing of WorldView DEMs to assess changes in glacier thickness, moraine collapse, and landslides. GLAM tool for GMELT. Products: Multitemporal database of lakes (supraglacial, ice-dammed, and moraine-dammed lakes) of Nepal and adjacent China. Classification of lakes according to hazard potential (including terrain parameters) and downstream vulnerabilities/risk, including infrastructure, residences, agriculture, and wildlife habitat. Peer-reviewed papers on shifting glacier hazard environment (glacial lakes, mass movements, GLOF triggers, and GLOF characterization in a context of other types of floods; assess most-hazardous lakes and identify looming hazards. Glacier surface flow fields and thickness changes and the damming moraines of selected glaciers and glacial lakes. Deposit relevant results in NSIDC’s GLIMS glacier database.