YAN Wei, HAN Ding, LU Wen, Lei Xiao-Long
.2012.Research of cloud-base height retrieval based on COSMIC occultation sounding data.Chinese Journal Of Geophysics,55(1): 1-15,doi: 10.6038/j.issn.0001-5733.2012.01.001
基于COSMIC掩星探测资料的云底高反演研究
严卫, 韩丁, 陆文, 雷霄龙
解放军理工大学气象学院, 南京 211101
Research of cloud-base height retrieval based on COSMIC occultation sounding data
YAN Wei, HAN Ding, LU Wen, Lei Xiao-Long
Institute of Meteorology, PLA University of Science and Technology, Nanjing 211101, China
Abstract:Based on the idea of retrieving cloud-base height by using the mutation of relative humidity profile when it comes into cloud, this paper gets information of cloud-base height by using COSMIC wet air data from November 2008 to January 2009, and after comparing with the results retrieved from radiosonde data, it acquires the following important conclusions: (1)When the temperature of cloud layer is between 0 and -40 Celsius Degree, this paper retrieves the cloud-base height when cloud phase is respectively thought as liquid cloud or ice cloud, and finds that it may fail to detect high cloud and multilayer cloud if cloud phase is considered as pure liquid; (2)COSMIC gets worse cloud-base height results for low cloud and better ones for high cloud and multilayer cloud, and its retrieval results are generally greater than radiosonde's; (3)To further analyze the differences of retrieval results between COSMIC and radiosonde when they both detect cloud, this paper discusses the retrieval results respectively as their cloud-layer numbers are equal or not. When the cloud-layer numbers are equal, the differences are larger in low-latitude regions and for the single layer cloud by calculating their mean and standard deviation, but they have consistent results for three-layer and four-layer cloud. When the numbers are different, some single layer clouds from COSMIC split up into multilayer clouds in the radiosonde results, which leads to the great differences between them.
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