title: Light-absorbing impurities accelerate glacier melt in the Central Tibetan Plateau.
abstract: Light-absorbing impurities (LAIs), such as organic carbon (OC), black carbon (BC), and mineral dust (MD) deposited on the glacier surface can reduce albedo, thus accelerating the glacier melt. Surface fresh snow, aged snow, granular ice, and snowpits samples were collected between August 2014 and October 2015 on the Xiao Dongkemadi (XDKMD) glacier (33°04'N, 92°04'E) in the central Tibetan Plateau (TP). The spatiotemporal variations of LAIs concentrations in the surface snow/ice were observed to be consistent, differing mainly in magnitudes. LAIs concentrations were found to be in the order: granular ice>snowpit>aged snow>fresh snow, which must be because of post-depositional effects and enrichment. In addition, more intense melting led to higher LAIs concentrations exposed to the surface at a lower elevation, suggesting a strong negative relationship between LAIs concentrations and elevation. The scavenging efficiencies of OC and BC were same (0.07±0.02 for OC, 0.07±0.01 for BC), and the highest enrichments was observed in late September and August for surface snow and granular ice, respectively. Meanwhile, as revealed by the changes in the OC/BC ratios, intense glacier melt mainly occurred between August and October. Based on the SNow ICe Aerosol Radiative (SNICAR) model simulations, BC and MD in the surface snow/ice were responsible for about 52%±19% and 25%±14% of the albedo reduction, while the radiative forcing (RF) were estimated to be 42.74±40.96Wm-2and 21.23±22.08Wm-2, respectively. Meanwhile, the highest RF was observed in the granular ice, suggesting that the exposed glaciers melt and retreat more easily than the snow distributed glaciers. Furthermore, our results suggest that BC was the main forcing factor compared with MD in accelerating glacier melt during the melt season in the Central TP.
authors.affiliation: State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Li
authors.affiliation: State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, China. Electronic address: shichang.kang@lzb.ac.cn.
authors.forename: Shichang
authors.initials: S
authors.lastname: Kang
authors.affiliation: State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Tanggula Cryosphere and Environment Observation Station, State Key Laboratory of Cryospheric Sciences, Lanzhou 730000, China.
authors.forename: Xiaobo
authors.initials: X
authors.lastname: He
authors.affiliation: Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, FIN-50130 Mikkeli, Finland.
authors.forename: Bin
authors.initials: B
authors.lastname: Qu
authors.affiliation: State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; Himalayan Environment Research Institute (HERI), Kathmandu, Nepal.
authors.forename: Lekhendra
authors.initials: L
authors.lastname: Tripathee
authors.affiliation: State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
authors.forename: Zhefan
authors.initials: Z
authors.lastname: Jing
authors.affiliation: State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China; Himalayan Environment Research Institute (HERI), Kathmandu, Nepal.
authors.forename: Rukumesh
authors.initials: R
authors.lastname: Paudyal
authors.affiliation: University of Chinese Academy of Sciences, Beijing 100049, China; Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
authors.forename: Yulan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, FIN-50130 Mikkeli, Finland.
authors.forename: Fangping
authors.initials: F
authors.lastname: Yan
authors.affiliation: Key Laboratory of Arid Climatic Change and Disaster Reducing of Gansu Province, Institute of Arid Meteorology, China Meteorological Administration, Lanzhou 730020, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Li
authors.affiliation: Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Chaoliu
authors.initials: C
authors.lastname: Li
keywords: Albedo reduction; Glacier melt; Light-absorbing impurities; Radiative forcing; Tibetan Plateau