Quantifying ice loss in the eastern Himalayas since 1974 using declassified spy satellite imagery
Himalayan glaciers are important natural resources and climate indicators for densely populated regions in Asia. Remote sensing methods are vital for evaluating glacier response to changing climate over the vast and rugged Himalayan region, yet many platforms capable of glacier mass balance quan...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-09-01
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| Series: | The Cryosphere |
| Online Access: | https://www.the-cryosphere.net/10/2203/2016/tc-10-2203-2016.pdf |
| Summary: | Himalayan glaciers are important natural resources and climate
indicators for densely populated regions in Asia. Remote sensing methods are
vital for evaluating glacier response to changing climate over the vast and
rugged Himalayan region, yet many platforms capable of glacier mass balance
quantification are somewhat temporally limited due to typical glacier
response times. We here rely on declassified spy satellite imagery and ASTER
data to quantify surface lowering, ice volume change, and geodetic mass
balance during 1974–2006 for glaciers in the eastern Himalayas, centered on
the Bhutan–China border. The wide range of glacier types allows for the
first mass balance comparison between clean, debris, and lake-terminating
(calving) glaciers in the region. Measured glaciers show significant ice
loss, with an estimated mean annual geodetic mass balance of −0.13 ± 0.06 m w.e. yr<sup>−1</sup> (meters of water equivalent per year) for 10 clean-ice
glaciers, −0.19 ± 0.11 m w.e. yr<sup>−1</sup> for 5 debris-covered glaciers,
−0.28 ± 0.10 m w.e. yr<sup>−1</sup> for 6 calving glaciers, and −0.17 ± 0.05 m w.e. yr<sup>−1</sup> for all glaciers combined. Contrasting
hypsometries along with melt pond, ice cliff, and englacial conduit
mechanisms result in statistically similar mass balance values for both
clean-ice and debris-covered glacier groups. Calving glaciers comprise
18 % (66 km<sup>2</sup>) of the glacierized area yet have contributed 30 %
(−0.7 km<sup>3</sup>) to the total ice volume loss, highlighting the growing
relevance of proglacial lake formation and associated calving for the future
ice mass budget of the Himalayas as the number and size of glacial lakes
increase. |
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| ISSN: | 1994-0416 1994-0424 |