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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. DOI: 10.3878/j.issn.1006-9895.2011.06.11
引用本文: 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. DOI: 10.3878/j.issn.1006-9895.2011.06.11
WANG Hui, LUO Yali, ZHANG Renhe. Analyzing Seasonal Variation of Clouds over the Asian Monsoon Regions and the Tibetan Plateau Region using CloudSat/CALIPSO Data[J]. Chinese Journal of Atmospheric Sciences, 2011, 35(6): 1117-1131. DOI: 10.3878/j.issn.1006-9895.2011.06.11
Citation: WANG Hui, LUO Yali, ZHANG Renhe. Analyzing Seasonal Variation of Clouds over the Asian Monsoon Regions and the Tibetan Plateau Region using CloudSat/CALIPSO Data[J]. Chinese Journal of Atmospheric Sciences, 2011, 35(6): 1117-1131. DOI: 10.3878/j.issn.1006-9895.2011.06.11

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: 利用2006年9月至2009年8月的CloudSat/CALIPSO资料, 分析了东亚季风区(EAMR)、印度季风区(IMR)、 西北太平洋季风区(WNPMR) 和青藏高原地区(TPR) 的云量和云层垂直结构(包括云层的垂直位置、物理厚度、相邻云层间的垂直距离和雷达反射率垂直分布)及其季节变化特征, 进一步分析了亚洲季风区低云量的分布及其与对流层低层稳定性 (LTS) 的相关。有如下结论: (1) 这期间, EAMR、IMR、WNPMR和TPR总云量分别为69%、72%、83%和69%, 其中单层云占56%(IMR和WNPMR) 至77%(TPR), 多层云中二层和三层云合起来占95%以上。IMR的总云量在夏季(>90%) 明显高于冬季(约50%), EAMR和TPR春夏季略高于秋冬季, 而WNPMR总云量的季节变化不大。(2) 同属热带季风区的IMR和WNPMR全年都有底部在10 km以上的冰晶云, 其月平均云量为20% (冬季)~70% (夏季); 海洋边界层云在WNPMR全年较常见(月平均云量为20%~40%), 而IMR的低云主要出现在夏季(20%~40%); 属副热带季风区的EAMR云层主要位于对流层中低层, 10 km以上高云仅在夏季较多(30%左右), 但其发生频率和垂直位置相对IMR和WNPMR的高云(12~16 km高度的云量为60%~70%) 较低; TPR的云主要位于4~11 km, 等高度上云内滴谱较宽。(3) 云顶在4 km以下的低云在亚洲季风区的分布在春秋季相似、夏冬季差异较大, 冬季低云量最多, 主要分布在西北太平洋、中国大陆南部及其以东的洋面和日本附近地区, 低云量为45%~70%; 低云量与LTS的相关性在冬季不强, 而其他季节相关性较好。(4) 这四个地区都以薄云为主, 有30%~40%的云层物理厚度小于1 km, 而且多层云中相邻云层间的垂直距离约有10%小于1 km, 说明现有大气环流模式需要提高垂直分辨率。

     

    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 Asian Monsoon 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(>90%) 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.

     

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