大气科学2011，Vol.35Issue(6)：1117-1131,15.
用CloudSat/CALIPSO资料分析亚洲季风区和青藏高原地区云的季节变化特征
Analyzing Seasonal Variation of Clouds over the Asian Monsoon Regions and the Tibetan Plateau Region using CloudSat/CALIPSO Data
摘要
Abstract
Using the CloudSat/CALIPSO data products during the period of September 2006 - August 2009, seasonal variations of cloud properties (including occurrence frequency, vertical location, physical thickness, distance between cloud layers, and vertical distribution of radar reflectivity) are contrasted among four regions: East AsianMonsoon Region (EAMR), Indian Monsoon Region (IMR), the Western North Pacific Monsoon Region (WNPMR), and the Tibetan Plateau Region (TPR). The geographical distribution of low-level clouds over the Asian monsoon regions and its correlation with atmospheric stability of the lower troposphere (LTS) are also analyzed The major findings are as follows: (1) During the period, the total cloud amounts are 69% (EAMR), 72% (IMR), 83% (WNPMR), and 69% (TPR), respectively, to which single-layer clouds contribute 56% (IMR and WNPMR) to 77% (TPR). The multi-layer clouds are mostly double-layered or triple-layered (fractions≥95%). In the IMR, the total cloud amount in summer (greater than 90%) is significantly larger than in winter (about 50%); the total cloud amounts are larger during spring and summer 090%) than autumn and winter (about 50%) in the EAMR and TPR; the seasonal variation is negligible over the WNPMR (2) Clouds located above 10 km containing small ice crystals prevail in the tropical monsoon regions (IMR and WNPMR) all the year round. Marine boundary layer clouds are common during each season in the WNPMR, in contrast to the IMR where low-level clouds occur mainly during summer. The EAMR clouds are located mostly below 10 km from autumn to spring. Although more clouds are present in the upper troposphere during summer than other seasons over the EAMR, their occurrences and vertical locations are lower than those in the IMR and WNPMR (cloud amount of 60%- 70% from 12 to 16 km heights). The TPR clouds are mostly located in the height range of 4 - 11 km, with cloud particles at the same height covering a wide range of size. (3) The geographical distributions of low-level clouds in the Asian monsoon region are similar between spring and autumn, and significantly distinct between summer and winter. Low-level clouds are the most abundant during winter (45%- 70%), located mainly in the western North Pacific, southern Chinese mainland and the oceans to its east, and the regions around Japan. The low-level cloud amount is correlated with LTS quite well except for winter. (4) The cloud layers are geometrically thin in the four regions, with 30%- 36% being thinner than 1 km. Moreover, the vertical distance between two consecutive layers in multilayered clouds with values less than 1 km accounts for about 10%. Both suggest a need to improve the vertical resolution of current general circulation models.关键词
亚洲季风区/青藏高原/云量/云垂直结构Key words
Asian monsoon region, Tibetan Plateau, cloud amount, cloud vertical structure分类
天文与地球科学引用本文复制引用
汪会,罗亚丽,张人禾..用CloudSat/CALIPSO资料分析亚洲季风区和青藏高原地区云的季节变化特征[J].大气科学,2011,35(6):1117-1131,15.基金项目
中国气象科学研究院基本科研业务费专项基金2007R001,国家自然科学基金资助项目40875064、40921003,气象行业专项GYHY200806020 （）
