中尺度对流系统中的湿中性层结结构特征

Structure Characteristics of Moist Neutral Stratification in a Mesoscale Convective System

基于CloudSat卫星获得的高分辨率中尺度对流系统垂直剖面结构,结合大气参量相对湿度和相当位温的诊断分析,在低纬度、中高纬度地区、陆地或海洋以及不同天气形势下,发现了多个非常典型的中尺度对流系统(MCS)内部具有湿中性层结特征的个例。进一步利用静止卫星普查到的东亚地区MCS分布情况,结合NCEP再分析资料诊断MCS重心位置处大气状态廓线,利用大量的例子从统计的角度揭示了湿中性层结结构特征在MCS中存在的普遍性,并且从动力学和热力学的角度探讨了湿中性层结结构在MCS发生和发展中所起到的作用。

Many vertical sections of Mesoscale Convective System （MCS） detected by CloudSat satellite in regions of high humidity have a structural trait whereby the equivalent potential temperature is close to uniform in the vertical. This is called the moist neutral stratification, commonly found in East Asia in low or medium-high latitudes, over land or sea. Further information regarding the centroid distribution of MCSs was obtained from geostationary satellite cloud infrared image, and the NCEP reanalysis data was used to diagnose some profiles of atmospheric parameters over the centroid of the MCSs. The statistical results show that a moist neutral stratification structure was common in the MCSs. The role that moist neutral stratification plays in the initiation and development of a MCS is discussed from a kinetic and thermodynamic point of view.