Acta Scientiarum Naturalium Universitatis Pekinensis

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The Climatic Characteristics of the Equatorial Zonal Circulation Retrieved with IR and WV Channels on Satellite

SHANG Shurong1,JIANG Shangcheng2   

  1. 1Hebei Meteorology Center of CAAC, Shijiazhuang, 050802;2Department of Geophysics, Peking University, Beijing, 100871
  • Received:2000-06-15 Online:2001-09-20 Published:2001-09-20



  1. 1民航河北省局气象台,石家庄,050802;2北京大学地球物理学系,北京,100871

Abstract: The equatorial zonal circulation is an important component of the tropical general circulation. It's activity and variation are effected both on the anomalies of the mid-high latitudes and the global general circulation. Due to the lack of traditional observation, it is actually not true to describe the zonal circulation over the tropics with conventional data. The OLR observed by satellite observations is appropriate for indicating the convection upward motion over tropics but not for describing the descending motion. It is possible to describe the subsidence over tropics by using HIRS-Tb12 (High-resolution Infra-red Radiation Sounder—HIRS, channel 12, 6.7μm bright temperature Tb12) observed by NOAA satellite. So that the equatorial zonal circulation can be retrieved both with IR and WV channels on the satellite. The climatic characteristics of the equatorial zonal circulation are studied by using monthly 17 years (1979—1995) OLR, HIRS-Tb12 and NCEP/NCAR 2.5°×2.5°reanalysis data.Comparing the OLR, FWV (calculated by HIRS-Tb12 and 500hPa ω climatic mean map, it is further confirmed that it's a good approach to retrieve the equatorial zonal circulation by using the IR(indicate ascending branch) and WV(indicate descending branch) channels. The definition of the index of zonal circulation with the OLR and FWV are presented and the 17 years mean annual and seasonal equatorial circulation are drawn. The climatic characteristics of the equatorial zonal circulation are analyzed in detail. Consequently the fore results of the other observation are corrected.

Key words: satellite, OLR, HIRS-Tb12, equatorial zonal circulation, Walker circulation

摘要: 利用1979—1995年共17年卫星观测的OLR、HIRS-Tb12与NCEP再分析的同期资料进行了分析研究。主要包括以下两部分:用OLR、FWV(Flux Water Vapour,是由HIRS-Tb12通过波耳兹曼公式换算得到的6.7μm水汽辐射通量密度,以便于与OLR比较)与NCEP再分析的500hPa ω 的年气候平均图进行比较,分析其异同,进一步证明了用卫星观测的红外,水汽双通道(OLR表示上升运动,FWV表示下沉运动)去反演纬向垂直环流是一个极好的途径。定义了卫星双通道反演的纬向垂直环流指数,利用该定义对卫星资料计算并反演了气候平均的全年及四季的纬向垂直环流,详细地讨论了它的气候学特征,并修正了过去的各种观测结果。

关键词: 卫星, OLR, HIRS-Tb12, 赤道纬向环流, Walker环流

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