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Enhanced Surface Warming and Accelerated Snow Melt in the Himalayas and Tibetan Plateau Induced by Absorbing AerosolsNumerical experiments with the NASA finite-volume general circulation model show that heating of the atmosphere by dust and black carbon can lead to widespread enhanced warming over the Tibetan Plateau (TP) and accelerated snow melt in the western TP and Himalayas. During the boreal spring, a thick aerosol layer, composed mainly of dust transported from adjacent deserts and black carbon from local emissions, builds up over the Indo-Gangetic Plain, against the foothills of the Himalaya and the TP. The aerosol layer, which extends from the surface to high elevation (approx.5 km), heats the mid-troposphere by absorbing solar radiation. The heating produces an atmospheric dynamical feedback the so-called elevated-heat-pump (EHP) effect, which increases moisture, cloudiness, and deep convection over northern India, as well as enhancing the rate of snow melt in the Himalayas and TP. The accelerated melting of snow is mostly confined to the western TP, first slowly in early April and then rapidly from early to mid-May. The snow cover remains reduced from mid-May through early June. The accelerated snow melt is accompanied by similar phases of enhanced warming of the atmosphere-land system of the TP, with the atmospheric warming leading the surface warming by several days. Surface energy balance analysis shows that the short-wave and long-wave surface radiative fluxes strongly offset each other, and are largely regulated by the changes in cloudiness and moisture over the TP. The slow melting phase in April is initiated by an effective transfer of sensible heat from a warmer atmosphere to land. The rapid melting phase in May is due to an evaporation-snow-land feedback coupled to an increase in atmospheric moisture over the TP induced by the EHP effect.
Document ID
20110013536
Document Type
Reprint (Version printed in journal)
Authors
Lau, William K. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Kim, Maeng-Ki (Kongju National Univ. Gongju, Korea, Republic of)
Kim, Kyu-Myong (Maryland Univ. Baltimore County Baltimore, MD, United States)
Lee, Woo-Seop (Kongju National Univ. Gongju, Korea, Republic of)
Date Acquired
August 25, 2013
Publication Date
April 9, 2010
Publication Information
Publication: Environmental Research Letters
Volume: 5
ISSN: 1748-9326
Subject Category
Geophysics
Report/Patent Number
GSFC.JA.4598.2011
Funding Number(s)
CONTRACT_GRANT: CATER 2009-1147
Distribution Limits
Public
Copyright
Other