祁连山地区云物理参数特征及其与降水的关系

Characteristics of cloud physical parameters and their relationship to the rainfall over Qilian Mountains Areas

利用2006年1月-2015年12月的中分辨率成像光谱仪数据和网格化地面降水资料对祁连山地区云参数的时空特征及其与降水的关系进行了分析.结果表明,云量、云水路径、云顶温度、云粒子有效半径的区域平均值分别为55.50%、148.95 g/m^2、-21.13℃、21.04μm.过去10 a间,云量、云水路径和云粒子有效半径分别下降了2.3%、21 g/m^2和0.51μm,云顶温度上升了1.9℃.夏季云水丰沛、云发展旺盛且云滴较小,冬季则相反.云参数的高、低值中心的空间分布与研究区域的山脉走向一致.乌鞘岭地区与降水相关的云参数条件相对最好,冬季云参数的空间分布相对于其他季节有明显的变化.季节降水效率的区域平均值分别为9.53%(春)、12.54%(夏)、8.85%(秋)、3.51%(冬)且高值区均位于主山脉区.降水效率与云水路径相关性最好,与云顶温度相关性最差.云量、云水路径、云顶温度与降水效率相关性最好的季节均为冬季,分别为0.62、0.88、-0.52,云粒子有效半径与降水效率相关性最好的是秋季,为-0.60.

The temporal and spatial characteristics of cloud parameters and the relationship with the precipitation efficiency over the Qilian Mountains were analyzed by using the moderate resolution imaging spectroradiometer data from January 2006 to December 2015,combined with grid ground precipitation data from China Meteorological Administration.The results showed that the regional averages of cloud amount(CA),cloud water path(CWP),cloud top temperature(CTT),cloud effective radius(CER)were55.50%,148.95 g/m^2,-21.13℃,21.04μm,respectively.Over the past 10 a,CA,CWP,CER decreased by 2.3%,21 g/m^2 and 0.51μm respectively,while CTT increased by 1.9℃.In summer,the cloud water was abundant and clouds became exuberant and the cloud droplets were small,while in winter it was just the opposite.The high and low centers of the cloud parameters were distributed along the direction of the mountain ranges in the study area.The cloud parameters condition related to the rainfall in the Wushaoling area were the best.The spatial distribution of cloud parameters in winter underwent obvious changescompared with other seasons.The seasonal regional mean values of precipitation efficiency were 9.53%(spring),12.54%(summer),8.85%(autumn)and 3.51%(winter).The high value area of precipitation efficiency in every season was located in the main mountain area.Precipitation efficiency had the best correlation with CWP and the worst with CTP.The best correlations between CA,CWP,CTT and precipitation efficiency were in winter,with values of 0.62,0.88 and-0.52 respectively,while the correlation between CER and precipitation efficiency was best in autumn,with a value of-0.60.