摘要
深对流在地-气系统的物质和能量交换中起着至关重要的作用,伴随而来的暴雨、雷电、冰雹等天气会对人类社会产生影响。利用CloudSat/CALIPSO和FY-2E卫星观测数据,研究了中国海域及周边地区非穿透性对流(DCwo)及穿透性对流(CO)的海-陆分布、云顶红外亮温和云团特征(包括对流系统(CS)和对流单体(CC)的面积、活跃性对流比、偏心率、最低亮温、平均亮温梯度)。结果发现:穿透性对流比非穿透性对流的云顶红外亮温更低,垂直高度上的雷达反射率更高;从发生次数来看,非穿透性对流/穿透性对流在海洋比陆地多,低纬度比高纬度多,夏季比其他季节多,冬季海陆差异最大;从云顶亮温的分布来看,海洋比陆地、穿透性对流比非穿透性对流集中分布区间的亮温值更低,穿透性对流的分布区间比非穿透性对流集出现较大面积的对流系统/对流单体,海洋穿透性对流的活跃性对流比相对较高;偏心率在0.5以上的发生频率较高,对流系统形状更偏向于圆形,在海洋上更加明显;穿透性对流在海陆上的最低亮温集中分布区间为190—195 K,比非穿透性对流的分布更集中,平均亮温梯度在0.1 K/km以下的发生频率较高。
Deep convection plays an important role in affecting the constituents and energy budget of the troposphere. It also brings severe weather like torrential rain, lightning and hail, which has various impacts on human society. Land-sea distributions, characteristics of infrared brightness temperature(BT) and properties of convective system(CS) with convective overshooting(CO) and deep convection without CO(DCwo) in China are analyzed based on the CloudSat/CALIPSO and FY-2 E datasets. Properties of CS, i.e., the area of CS, the area of convective cluster(CC), the convective fraction, the eccentricity, the minimum BT and the average gradient of BT are evaluated. The results indicate that lower BT in cloud top and higher radar reflectivity in the vertical are detected in CO compared to that detected in DCwo. The frequency of CO or DCwo is higher over the sea and the low latitudes as well as in the summer. At the same time, the biggest difference in the frequency of CO/DCwo between the land and the sea is found in the winter. The BT of cloud top over the sea and for CO are lower than that over the land and for DCwo, respectively. The distribution interval of CO is more concentrated than that of DCwo. The frequency of CS or CC decreases with the increase of area. Bigger CS or CC is more likely to occur in CO and over the sea. The value of convective fraction is higher over the sea than over the land. The occurrence of eccentricity of CS larger than 0.5, which implies a circular shape of the CS, is more frequent. Compared to that over the land, this phenomenon is more obvious over the sea. The concentrated distribution interval of minimum BT is 190-195 K in CO and over the sea, which is smaller than that in DCwo. The concentrated distribution interval of average gradient of BT is below 0.1 K/km.
作者
杨冰韵
吴晓京
王曦
YANG Bingyun;WU Xiaojing;WANG Xi(National Satellite Meteorological Center,Beijing 100081,China)
出处
《气象学报》
CAS
CSCD
北大核心
2019年第2期256-267,共12页
Acta Meteorologica Sinica
基金
国家自然科学基金项目(41675110
41575049)
公益性行业(气象)科研专项(GYHY201506022)
