宁夏中部夏季层状云特征参数与降水相关性研究

Study on the Correlation between Stratiform Cloud Characteristic Parameters and Precipitation in Summer in Central Ningxia

以宁夏中部2016年、2017年夏季8次层状云降水过程为例,基于FY-2G卫星反演的云特征参数和6个国家气象站的降水观测资料,根据云特征参数和降水强度分级方法,统计并分析层状云的结构特征参数与降水的相关性.结果表明,在降水背景下,平均云顶高度为4.0~5.3 km、云顶温度为-19.0~-12.0℃、过冷层厚度为2.0~2.8 km、云光学厚度为11.0~18.0、云粒子有效半径为8.2~11.8μm、云中液态水的质量含量为100~170 g/m^(2)、云黑体亮度温度为-18.0~-5.0℃;云特征参数的空间分布与累计降水量分布趋势相反,其分级自东南向西北递增;云顶高度、云顶温度、云光学厚度和云黑体亮度温度等对降水的响应较好;云特征参数在有降水情况下的频数分布较无降水情况下的更趋于向高等级集中;云特征参数分级较高的云系发生强降水的概率较大、发生弱降水的概率较小,云特征参数分级较低的云系发生强降水的概率较小、发生弱降水的概率较大.研究结果可为分析云降水的发展演变规律、识别人工影响天气的播云条件和效果等提供参考.

Taking eight stratiform cloud precipitation processes in the summer of 2016 and 2017 in central Ningxia as an example,based on the cloud characteristic parameters retrieved by FY-2G satellite and the precipitation observation data of six national meteorological stations,the correlation between stratiform cloud structure characteristic parameters and precipitation was analyzed by referring to the cloud characteristic parameters and precipitation intensity classification method.The results show that under the background of precipitation,the average cloud top height is 4.0 to 5.3 km,the cloud top temperature is-19.0℃to-12.0℃,the thickness of the supercooled layer is 2.0 to 2.8 km,the cloud optical thickness is 11.0 to 18.0,the effective radius of cloud particles is 8.2 to 11.8μm,the mass content of liquid water in cloud is 100 to 170 g/m^(2),and the brightness temperature of cloud black body is-18.0℃to-5.0℃.The spatial distribution of cloud characteristic parameters is opposite to the distribution trend of cumulative precipitation,and its classification increases from southeast to northwest.Parameters such as cloud top height,cloud top temperature,cloud optical thickness and cloud blackbody brightness temperature respond well to precipitation.The frequency distribution of cloud characteristic parameters in the case of precipitation tends to be higher than that in the case of no precipitation.The probability of heavy precipitation is larger and the probability of weak precipitation is smaller in the cloud system with higher cloud characteristic parameter classification.The probability of heavy precipitation is smaller and the probability of weak precipitation is larger in the cloud system with lower cloud characteristic parameter classification.The research results can provide a reference for analyzing the development and evolution of cloud precipitation and identifying the conditions and effects of artificial weather.