用TRMM资料研究江淮、华南降水的微波特性
STUDY OF MICROWAVE CHARACTERISTICS OF RAINFALL OVER SOUTH CHINA AND YANGTZE RIVER BASIN USING TRMMDATA
-
摘要: 热带测雨卫星TRMM (Tropical Rainfall Measuring Mission) 于1997年11月发射成功, 其首次携带了空载雷达, 有关资料已在网上对公众发布。利用热带测雨卫星上的微波成像仪TMI (TRMM Microw ave Imager) 资料以及其和测雨雷达TRMM/PR (Precipitation Radar) 资料联合反演的地面瞬时降水产品, 采用散射指数 (Is) 法从理论上探讨了我国江淮、华南降水尤其是暴雨的微波特性, 其中Is表达式通过江淮、华南晴空TMI资料统计回归得到。以联合反演的地面瞬时降水产品为真值, 用面积相当法对14个降水个例求Is降水阈值, 研究了阈值和降水面积以及85.5 GHz垂直通道最低亮温的关系, 并寻求了Is和降水的相关特征。研究表明:Is降水阈值随降水面积的增大或85.5 GHz垂直通道最低亮温的降低有增高的趋势; Is与强对流性降水瞬时雨强对应很好, Is≥60 K是一个好的暴雨指标。最后进行了初步的雨强反演试验研究, 由于TMI资料分辨率的提高以及时空配合较好的真值, 反演的地面瞬时降水与真值相关效果大大提高。Abstract: TRMM (Tropical Rainfall Measurement Mission) was launched in December 1997, which carried a space radar for the first time and the related data have been made available to the public users since June 1998.The microwave characteristics of rainfall over South China and the Yang tze river basin are investigated by using TMI (TRMM Microwave Imager) data and TRMM-derived precipitation products through Is (Scattering Index) algorithm.The expression of the Isis regressed by the TMI data on sunny days.For 14 rainfall cases, the relationship between the Isprecipitation threshold obtained through the "area equal" method and the precipitation area and the coldest top temperature of 85.5 GHz vertical channel is investigated.At the same time, the correlation between Isand surface instantaneous rain intensity is studied.The result shows that the Isthreshold has the increasing tendency when the precipitation area increases or the top temperature decreases, and Is≥60 K is a good index of rainstorm.The instantaneous rain intensity is retrieved, and it is found that Iscan be used to retrieve rain intensity better because of the improvement of data resolution and the temporal and spatial consistency of the data.
-
Key words:
- TMI;
- Scattering index;
- Threshold;
- Instantaneous rain intensity
-
表 1 TMI各通道参数
表 2 面积相当法得到的阈值及其准确性检验
表 3 14个个例的降水面积、最低云顶亮温和Is降水阈值
-
[1] 陈渭民, 夏浣清, 陈光宇.卫星气象学.北京:气象出版社, 1989.1-9. [2] Cheng M.Estimation of Precipitation Using Satellite, Radar and Rain Gauge :[ Ph.D.Thesis].University of Bristol, 1994. [3] Cheng M, Brown R, Collier C G.Delineation of rain areas using Meteosat infrared and visible data in the region of the United Kingdom.Journal of Applied Meteorology, 1993, 32 :884-898. doi: 10.1175/1520-0450(1993)032 & lt; 0884:DOPAUM & gt; 2.0.CO; 2 [4] 周秀骥.大气微波辐射及遥感原理.北京:科学出版社, 1982.71-88. [5] Liu G, Curry J A.Retrieval of precipi tation from satellite microwave measurement using both emission and scattering.Journal of Geop.Hysical Research, 1992, 97:9959-9974. doi: 10.1029/92JD00289 [6] Spencer R W, Goodman H M, Hood R E.Precipitation retrieval over land and ocean with the SSM/ I:Identification and characteristics of the scat tering signal.Journal of Atmospheric and Oceanic Technology, 1989, 6(4):254-273. [7] Kummerow C D, Simpson J, Thiele O, et al.The status of the Tropical Rainfall Measuring Mission (TRM M) after two years in orbit.Journal of Applied Meteorology, 2000, 39(12):1965-1982. doi: 10.1175/1520-0450(2001)040 & lt; 1965:TSOTTR & gt; 2.0.CO; 2 [8] Haddad Z S, Smith E A, Kummerow C D, et al.The T RMM " day-1" radar/ radiometer combined rain-profiling algorithm.Journal of the Meteorological Society of Japan, 1997, 5(4):799-809. [9] Cheng Minghu, He Huizhong, Mao Dongyan, et al.Study of 1998 heavy rainfall over the Yangtze river basin using T RMM data.Advances in Atmospheric Sciences, 2001, 18 :387-396. doi: 10.1007/BF02919317 [10] Kummerow C D, Barnes W, Kozu T, et al.The Tropical Rainfall Measuring Mission (T RMM) package.Journal of Atmospheric and Oceanic Technology, 1998, 15(6):809-817. [11] Aonashi, Kazumasaand L G.Passive microwave precipitation retrievals using TMI during the Baiuperiod of 1998.PartⅠ :Algorithm description and validation.Journal of Applied Meteorology, 2000, 39(12):2024-2037. doi: 10.1175/1520-0450(2000)039 & lt; 2024:PMPRUT & gt; 2.0.CO; 2 [12] Shin D, North G R, Bowman K P.A summary of reflectivity profiles from the first year of T RMM radar data.Journal of Climate, 2000, 13 :4072-4086. [13] Grody N C.Classification of snow cover and precipitation using the Special Sensor Microwave / Imager (SSM/ I).J.Geophys.Res., 1991, 96 :7423-7435. doi: 10.1029/91JD00045 [14] Ferraro R R, Marks G F.The developmen t of SSM/ I rain-rate ret rieval algorithms using ground-based radar measurements.Journa l of Atmospheric and Oceanic Technology, 1995, 12(8):755-770. https://www.researchgate.net/publication/249604298_The_Development_of_SSMI_Rain-Rate_Retrieval_Algorithms_Using_Ground-Based_Radar_Measurements