Sources, evolution and impacts of EC and OC in snow on sea ice： a measurement study in Barrow, Alaska  

作　　者：Tingfeng Dou Cunde Xiao Zhiheng Du J. J. Schauer Hong Ren Baozhu Ge Aihong Xie Jihua Tan Pingqing Fu Yuanxun Zhang 

机构地区：[1]College of Resources and Environment, University of Chinese Academy of Sdences, Beijing 100049, China [2]State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China [3]State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China [4]Environmental Chemistry and Technology Program, University of Wisconsin-Madison, Madison, Wl 53706, USA [5]state Key Laboratory of Atmospheric Boundary Layer Physics-an-d Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China [6]Huairou Eco-Environmental Observatory, Chinese Academy of Sciences, Beijing 101408, China [7]Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China

出　　处：《Science Bulletin》2017年第22期1547-1554,共8页科学通报（英文版）

基　　金：supported by the Ministry of Science and Technology of China(MOST, 2013CBA01804);the National Nature Science Foundation of China (41425003,41401079, 41476164 and 41625014);the key project of CAMS:Research on the Key Processes of Cryospheric Rapid Changes (KJZD-EW-G03);the Opening Founding of State Key Laboratory of Cryospheric Sciences(SKLCSOP-2016-03);the State Key Laboratory of Cryospheric Sciences (SKLCS-ZZ-2017)

摘　　要：Based on the field measurements in Barrow, Alaska within the period of April-May 2015, we investigate the sources and variations of elemental carbon(EC) and organic carbon(OC) in the surface layer of snowpack on sea ice, and estimate their effects on the sea ice albedo. Results show that the snow OC in Barrow are from natural sources(e.g. terrestrial higher plants and micro-organisms) mainly, as well as biomass burning(e.g. forest fires and straw combustion) as an important part. Both EC and OC can accumulate at the snow surface with snow melt. The variations in EC and OC and liquid water content in the snow layer are well consistent during the snow-melting period. A higher rate of snow melt implied a more efficient enrichment of EC and OC. In the last phase of snow melt, the concentration increased to a maximum of 16.2 ng/g for EC and 128 ng/g for OC, which is ~10 times larger than those before snow melt onset. Except for the dominant influence of melt amplification mechanism, the variation in concentrations of EC and OC could be disturbed by the air temperature fluctuation and snowfall. Our study indicates that the lightabsorbing impurities contributed 1.6%-5.1% to the reduction in sea ice albedo with melt during the measurement period. The significant period oflight-absorbing impurities influencing on sea ice albedo begins with the rapid melting of overlying snow and ends before the melt ponds formed widely, which lasted for about 10 days in Barrow, 2015.Based on the field measurements in Barrow, Alaska within the period of April-May 2015, we investigate the sources and variations of elemental carbon （EC） and organic carbon （OC） in the surface layer of snow- pack on sea ice, and estimate their effects on the sea ice albedo. Results show that the snow OC in Barrow are from natural sources （e.g. terrestrial higher plants and micro-organisms） mainly, as well as biomass burning （e.g. forest fires and straw combustion） as an important part. Both EC and OC can accumulate at the snow surface with snow melt. The variations in EC and OC and liquid water content in the snow layer are well consistent during the snow-melting period. A higher rate of snow melt implied a more efficient enrichment of EC and OC. In the last phase of snow melt, the concentration increased to a maximum of 16.2 ng/g for EC and 128 ng/g for OC, which is ~10 times larger than those before snow melt onset. Except for the dominant influence of melt amplification mechanism, the variation in concentrations of EC and OC could be disturbed by the air temperature fluctuation and snowfall. Our study indicates that the light- absorbing impurities contributed 1.6^-5.1 ~ to the reduction in sea ice alhedo with melt during the mea- surement period. The significant period of light-absorbing impurities influencing on sea ice albedo begins with the rapid melting of overlying snow and ends before the melt ponds formed widely, which lasted for about 10 days in Barrow, 2015.

关 键 词：ARCTIC EC OC Sea ice ALBEDO BARROW 

分 类 号：P731.15[天文地球—海洋科学]