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SUMMARY:Characteristics and changes of glaciers\, rock glaciers and glacia
 l lakes in High Mountain Asia since the 1960s - Dr. Tobias Bolch\, Univers
 ity of St. Andrews
DTSTART:20200206T160000Z
DTEND:20200206T170000Z
UID:TALK139291@talks.cam.ac.uk
CONTACT:Frazer Christie
DESCRIPTION:High Mountain Asia (HMA) contains large glaciated areas and ha
 s great climatic diversity. Large parts are moreover influenced by permafr
 ost and numerous rock glaciers also exist. While previous studies have sho
 wed that the glaciers in HMA have lost a significant amount of mass overal
 l\, the mass balance is variable and some glaciers have gained mass. While
  the general mass balance trends are well known\, several important factor
 s and processes in the evolution of debris-covered glaciers and rock glaci
 ers are less well understood. One reason is the lack of long-term observat
 ions. To overcome these obstacles we use declassified high-resolution ster
 eo Corona data from the 1960s and stereo Hexagon data from the 1970s in co
 njunction with more recent high-resolution stereo satellite data. Results 
 show that many large rock glaciers evolved from moraines and debris-covere
 d glaciers under permafrost conditions. Rock glaciers in the Tien Shan and
  Himalaya showed on average no significant surface elevation changes but t
 ypically surface lowering in the upper reaches and elevation gain at the f
 ront\, indicating ice transported by downslope creep. Preliminary results 
 of glacier mass balances revealed increasing mass loss on average\, with t
 he highest mass loss occurring in northern Tien Shan and Nyainqentanglha a
 nd with balanced mass budgets in eastern Pamir since the 1960s. The debris
 -covered glaciers at Mt. Everest showed significant surface lowering of pa
 rtly more than 100 m. The highest lowering occurred at Imja glacier where 
 the proglacial Imja lake expanded rapidly since the 1960s. The increased m
 ass loss of glaciers with pro-glacial lakes could be confirmed for the who
 le Himalaya\, but no substantial difference in the mass loss of debris-cov
 ered and clean-ice glaciers since the 1970s could found. Glacial lakes do 
 not only influence glacier mass loss but prose also a serious threat to th
 e society. Analysis of the lakes in Tibet showed partly rapid lake growth\
 , with 16% of all glacial lakes threatening human settlements. These resul
 ts are important for stakeholders either directly for planning hazard miti
 gation measures or indirectly as they provide important baseline data to i
 mprove glacio-hydrological models.
LOCATION:Scott Polar Research Institute\, main lecture theatre
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