新疆层云和层积云冰粒子属性的季节变化

Seasonal variations of microphysical properties of ice particles for stratus and stratocumulus in Xinjiang

利用CloudSat卫星资料,选取冰粒子的等效半径(IER)、数浓度(INC)、含水量(IWC),统计分析了层云、层积云微物理量的垂直分布和季节变化。层云/层积云小粒子(0~50μm)、中等粒子(50~80μm)、大粒子(≥80μm)出现频率分别为18.7%/16.3%、77.6%/62.6%、3.7%/21.2%。在IER垂直分布上,层云小、中等粒子在云层中部出现较多,层积云小粒子在云层上部出现较多,中等、大粒子在云层中部出现较多。层云/层积云INC低值段(0~50 L^(-1))、中值段(50~100 L^(-1))、高值段(≥100 L^(-1))出现频率分别为90.1%/76.5%、9.6%/19.5%、0.3%/4.1%。在INC垂直分布上,层云低、中值段在云层中部出现较多,层积云低、中值段分别在云层中部、上部出现较多。层云/层积云IWC低值段(0~50 mg·m^(-3))、中值段(50~100 mg·m^(-3))、高值段(≥100 mg·m^(-3))出现频率分别为96.7%/82.8%、3.2%/13.4%、0.1%/3.7%。在IWC垂直分布上,层云低值段在云层中部出现较多,层积云低、中值段分别在云层中部、上部出现较多。

The vertical distributions and seasonal variations of microphysical quantities for stratus and stratocu- mulus were analyzed in term of ice particle equivalent radius （IER）, the number concentration of ice particles （INC）, ice water content （IWC） by using CloudSat satellite data. The results were of great significance for carry- ing out artificial precipitation operation. The occurrence frequencies of the small particles （0-50 μm）, medium particles （50-80 μm）, large particles （over 80μm） in stratus （stratocumulus） were 18.7% （16.3%）, 77.6% （62.6%） and 3.7% （21.2%）, respectively. In the vertical distribution of IER, small and medium particles distrib- uted over the stratus and more frequently appeared in the middle parts, while large particles mainly distributed in the bottom parts. Meanwhile, for stratocumulus, except for winter, the distribution of IER were observed over the clouds; more small particles appeared in the upper part, more medium and large particles appeared in the middle parts. In the vertical direction, the stratification for stratus was obvious while it for stratocumulus was not obvi- ous. The occurrence frequencies of ice number concentration （INC） in low value （0-50 L-1） , median value （50-100 L-1） and high value （more than 100 L-1） for stratus （stratocumulus） were 90.1% （76.5%） , 9.6% （19.5%） and 0.3% （4.1%）, respectively. In the vertical distributions of INC, the low value oflNC distributed over the stratus, and the distributions of medium value was in middle and upper parts while the distributions of low and median value appeared more frequently in middle parts. At the same time, the distribution of low value of INC was over the stratocumulus, the distribution of medium value was in middle and upper parts while the dis- tribution of low and median value oflNC appeared more frequently in middle and upper part. The occurrence fre- quencies of ice water content （IWC） in low value （0-50 mg. m-3）, median value （50-100 mg. m-3） and high val- ue （more than 100 mg. m-3） for stratus （stratocumulus） were 96.7% （82.8%）, 3.2% （ 13.4%）, 0.1% （3.7%）, re- spectively. In the vertical distributions oflWC, the low value oflWC distributed over the stratus, and the distribu- tions of medium value of IWC was in middle parts, the distribution of low value oflWC appeared more frequent- ly in middle parts. At the same time, the distributions of low value and medium value of IWC were over the strato- cumulus, high value was in the upper parts, low and median values appeared more frequently in the middle and upper parts.