2018年青海人工增雨天气环流形势及作业条件统计分析

Analysis of circulation situation and operating conditions for artificial precipitation enhancement in Qinghai in 2018

对2018年飞机人工增雨作业时的77个天气样本进行分析,以大气环流形势配合冷空气入侵青海的不同路径将人工增雨降水过程分为4种环流型:两槽一脊型、东高西低型、纬向环流型、横槽转竖型。作业云系以层状云和积层混合云为主;主要作业层风速在16 m·s^(-1)左右;作业层主导风向在230°~280°。雷达回波强度和雷达回波顶高在4种环流型中没有明显区别。卫星反演云顶高度中东高西低型云系平均发展较深厚,纬向环流型和横槽转竖型中云系发展较高但并不深厚;云顶温度最低在-40℃;最大光学厚度在13左右;过冷层厚度在2.7 km左右。云内微观条件中:有效粒子半径在13μm左右;液水路径在东高西低型中较高在209μm左右。

Based on analysis of 77 samples of artificial precipitation operation in 2018,the artificial precipitation process was divided into four types of atmospheric circulation patterns based on the paths of the cold air intrusioninto Qinghai under certain atmospheric circulation situation:‘Two-trough and one-ridge’,‘East-high and west-low’,‘Zonal circulation’and‘Transverse to vertical’.The cloud system for operation was dominated by stratiform cloud and stratiform mixed cloud.The wind speed of the main operating layer was about 16 m·s^(-1),andthe dominant wind direction was between 230 and 280 degrees.The differencesof radar echo intensity and radar echo ceiling height was negligible among the four circulation patterns.Satellite-retrieved cloud development were relatively deep,and cloud top height is relatively high in the Middle East and low in the west.The cloud top height of the cloud with‘zonal circulation’type and the‘transverse to vertical’type was relatively high but the development of cloud systems was not deep.The lowest cloud top temperature was-40℃.The maximum optical thickness was about 13.The thickness of the supercooled layer was about 2.7 km.From the perspective of cloud microphysics,the effective particle radius was around 13 microns,andthe liquid water path of clouds in the‘East-high and west-low’type was about 209 microns.