Comparison of CloudSat Cloud Liquid Water Paths in Arctic Summer Using Ground-Based Microwave Radiometer

作     者：LIU Shuang Georg Heygster ZHANG Suping 

作者机构：College of Physical and Environmental Oceanography Ocean University of China Qingdao 266100 P. R. China Institute of Environmental Physics University of Bremen Bremen 28357 Germany 

出 版 物：《Journal of Ocean University of China》 (中国海洋大学学报（英文版）)

年 卷 期：2010年第9卷第4期

页      面：333-342页

学科分类：07[理学] 070601[理学-气象学] 08[工学] 0706[理学-大气科学] 0825[工学-航空宇航科学与技术] 

基　　金：ASCOS was made possible by grants from DAMOCLES and the Knut and Alice Wallenberg Foundation and was organized by the Swedish Polar Research Secretariat 

主　　题：CloudSat liquid water path Arctic microwave radiometer collocation Oden 

摘      要：Arctic clouds strongly influence the regional radiation balance, temperature, melting of sea ice, and freezing of sea water. Despite their importance, there is a lack of systematic and reliabie observations of Arctic clouds. The CloudSat satellite launched in 2006 with a 94GHz Cloud Profiling Radar （CPR） may contribute to close this gap. Here we compare one of the key parameters, the cloud liquid water path （LWP） retrieved from CloudSat observations and from microwave radiometer （MWR） data taken during the ASCOS （Arctic Summer Cloud Ocean Study） cruise of the research vessel Oden from August to September 2008. Over the 45 days of the ASCOS cruise, collocations closer than 3 h and 100 km were found in only 9 d, and collocations closer than 1 h and 30 km in only 2 d. The poor correlations in the scatter plots of the two LWP retrievals can be explained by the patchiness of the cloud cover in these two days （August 5th and September 7th）, as confirmed by coincident MODIS （Moderate-resolution Imaging Spectroradiome- ter） images. The averages of Oden-observed LWP values are systematically higher （40-70 g m-2） than the corresponding CloudSat observations （0-50 g m2）. These are cases of generally low LWP with presumably small droplets, and may be explained by the little sensitivity of the CPR to small droplets or by the surface clutter.