青藏高原地区云出现概率及其辐射强迫变化特征  

Cloud occurrence probability and its radiative forcing characteristics in Qinghai-Tibet Plateau

作　　者：位晶 段克勤 辛蕊 WEIJing;DUAN Keqin;XIN Rui(School of Geography and Tourism,Shaanxi Normal University,Xi'an 710000,China)

机构地区：[1]陕西师范大学地理科学与旅游学院,陕西西安710000

出　　处：《冰川冻土》2020年第2期368-377,共10页Journal of Glaciology and Geocryology

基　　金：国家自然科学基金项目(41771030,41571062)资助。

摘　　要：云辐射强迫是地气能量平衡的关键要素,为深入认识青藏高原云的辐射强迫作用,选取高原3个典型地区(西部半干旱地区A、藏东南湿润半湿润地区B和北部干旱地区C),利用CloudSat卫星的2B-CLDCLASS和2B-FLXHR资料对比分析了三个地区云出现概率,并分析了地表处高、中、低云的长、短波及净辐射强迫的年变化和季节变化。结果表明:受地形和季风影响,总云出现概率的年变化基本表现为B地区最高,A地区最低。云辐射强迫与云出现概率存在明显的正相关,且净辐射强迫常年为负值。湿润地区总云所产生的净辐射强迫平均值为-153.6W·m-2,约为干旱地区(-47.1W·m-2)的3倍,其对地面的冷却作用明显高于干旱地区。低云作为高原的主导云,其所产生的长短波及净云辐射强迫都明显高于其他云类,湿润地区低云短波辐射强迫值约是干旱地区的2倍,净辐射强迫则是干旱地区的3倍。各类云的净辐射强迫主要由短波云辐射强迫决定,除干旱区冬季高云和中云对地面起加热作用外,各地区云类均对地表起冷却作用。该研究结果有助于进一步认识青藏高原云与辐射之间的相互作用。Cloud plays an important role in regulating the radiation budget of the earth-atmosphere system. The cloud-induced radiative forcing is several times than that caused by the doubling of greenhouse gases. The cloud system of the Qinghai-Tibet Plateau serves as an important link between various local climates and even global climate. It is of great significance to study the radiation effects of clouds. Three regions(Regions A,B and C)in the Qinghai-Tibet Plateau were selected to compare and analyze the annual and seasonal changes of cloud amount,longwave radiation,shortwave radiation and net radiative forcing of the cloud at the surface by using the CloudSat satellite’s2 B-CLDCLASS and2 B-FLXHR data. The results showed that,influenced by the geographical location and monsoon,the annual changes in the total cloud amount basically appear a maximum in Region B and a minimum in Region A. The change in cloud radiative forcing is consistent with cloud amount,and net radiative forcing is negative in the whole year. The average net radiative forcing generated by the total cloud in the humid regions is-153.6 W·m-2,which is about3 times than that in the arid regions(-47.1 W·m-2),and its cooling effect on the surface is significantly higher than that in the arid regions. The Qinghai-Tibet Plateau is dominated by low clouds. The seasonal changes of various cloud types in the Region A are high in summer and low in winter,while in the Region B and Region C,in spring and summer are basically higher than those in autumn and winter. The seasonal change of cloud radiative forcing is greater in summer and autumn,followed by in spring and winter. Cloud shortwave radiative forcing is mainly affected by the occurrence probability of cloud and the change of surface albedo. Longwave radiation forcing is affected by cloud bottom height and cloud bottom temperature. The net radiative forcing of various types of clouds is mainly determined by shortwave cloud radiative forcing and the overall cooling effect on the surface(except for the h

关 键 词：青藏高原 云类型 云辐射强迫 

分 类 号：P426.5[天文地球—大气科学及气象学]