傅云飞 ,冯静夷 ,朱红芳 ,李锐,刘栋 . 2005. 西太平洋副热带高压下热对流降水结构特征的个例分析[J]. 气象学报, 63(5):750-761, doi:10.11676/qxxb2005.072
西太平洋副热带高压下热对流降水结构特征的个例分析
STRUCTURES OF A THERMAL CONVECTIVE PRECIPITATIONSYSTEM HAPPENED IN CONTROLLING OF THEWESTERN SUBTROPICAL PACIFIC HIGH
投稿时间:2005-03-08  修订日期:2005-05-25
DOI:10.11676/qxxb2005.072
中文关键词:  热对流降水,副热带高压,热带测雨卫星,测雨雷达,红外辐射温度
英文关键词:Thermal convective system, Subtropical high, TRMM PR and IR.
基金项目:国家重点基础研究专项经费(2004CB418304)、中国科学院知识创新工 程重要方向项目基金(ZKCX2-SW-210)、国家自然科学基金(40175015,40375018)、国家自然科学基金海外杰出青年基金(40428006)、王宽诚教育基金
作者单位
傅云飞 中国科学技术大学地球与空间科学学院合肥, 230026 
冯静夷 安徽省人工影响天气办公室合肥230026
安徽省气象台合肥230026 
朱红芳 安徽省人工影响天气办公室合肥230026
安徽省气象台合肥230026 
李锐 中国科学技术大学地球与空间科学学院合肥230026 
刘栋 中国科学技术大学地球与空间科学学院合肥230026 
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中文摘要:
      利用热带测雨卫星的测雨雷达和红外辐射计的探测结果,对2003年8月2日15时(北京时)中国东南部副热带高压下发生的热对流降水结构特征、云和降水云之间的关系进行了分析研究。大气背景分析表明,500 hPa副热带高压中心附近的较强上升运动和850 hPa的水汽通量辐合为此次午后热对流降水云团的发生提供了动力和水汽条件。热带测雨卫星的测雨雷达探测结果表明,热对流降水云团的水平尺度多为30~40 km,平均垂直尺度均超过10 km,最高达17.5 km;云团的最大近地面雨强超过50 mm/h。热对流降水云团的平均降水廓线表明,其最大降水率出现在5 km的高度,这一高度比估计的环境大气0 ℃层高度低1 km。与“98.7.20"中尺度强降水的对流降水廓线比较表明,两者的最大降水率高度相同,但热对流降水云团更深厚;在4 km高度至近地面,热对流的降水率减少速度比“98.7.20"强对流降水的快,表明前者雨滴在下降过程中因气温高而发生强烈蒸发。对降水云团顶部特征与近地面雨强关系的分析结果表明,雨顶高较低时,云顶高度变化范围大;当雨顶越高时,云顶高度与雨顶高度越相近;平均而言,给定地面降水率,云顶高度比雨顶高度高出1~4 km;当近地面雨强越大,则云顶高度和雨顶高度越高、且越相近。结果还表明,非降水云面积约占86%,晴空面积仅占2%,而降雨云面积约为云面积的1/8。
英文摘要:
      A thermal convective precipitating cloud system occurred in the southeastern mainland of China at 15:00 on August 2, 2003 under controlling of the western subtropical Pacific high was studied by using TRMM PR and IR measurements. Rainfall structures in both horizontal and vertical, relationship among rain-top, cloud-top and surface rainfall rate were particularly analyzed. Results show that a strong ascending air at 500 hPa and a strong convergence of moisture flux at 850 hPa near the center of the western subtropical Pacific High supply necessary conditions both in dynamics and moisture for the occurrence of the thermal convective rainfall system. TRMM PR detective shows that the horizontal scale of the thermal convective precipitating clouds are about 30-40 km mainly, and their averaged vertical scale is above 10 km, the maximum can reach to 17.5 km. The maximum rainfall rate near surface of those clouds is beyond 50 mm/h. The mean precipitation profile of those clouds shows their maximum rainfall rate at 5 km altitude that is 1 km lower than the estimated freezing level of the environment. Comparing with the mesoscale convective system of “98.7.20”, both systems have the same altitude of the maximum rainfall rate displayed from both mean precipitation profiles. But the thermal convective precipitating system is much deeper than that mesoscale convective system. From 4 km to near surface, profiles show that rainfall rate reducing in the thermal convective system is faster than that in the mesoscale convective system, which implies a strong droplet evaporation process occurring in the former system. Relationship among cloud-top, rain-top and surface rainfall rate analysis indicates a large amplitude variation of cloud-top when rain-top is lower. On the contrary, the higher the rain-top, the more consistent both cloud-top and rain-top is. Generally, cloud-top is 1-4 km higher than rain-top for a given surface rainfall rate. The bigger the surface rainfall rate, the higher and more consistent both cloud-top and rain-top is. Finally, results reveal that area fractions of no-precipitating clouds and clear sky are 86% and 2%, respectively. The area fraction of precipitating clouds is only about 1/8 that of no -precipitating clouds.
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