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    辽宁两类暴雨期间东亚静止卫星成像仪资料观测特征

    The Observation Characteristics of East Asia Geostationary Satellite Imager Data during Two Types of Rainstorm in Liaoning

    • 摘要: 对冷涡和副热带高压背景下辽宁地区4次降水过程进行了分析,探讨了风云四号A星、B星和葵花8/9号(分别简称为FY-4A、FY-4B和H 8/9)静止气象卫星的红外通道亮温和水汽通道亮温之间的相关性,同时利用FY-4B、ERA5再分析和自动气象站资料对比分析了不同天气系统背景下降水云的观测特征差异及成因。结果表明: FY-4B和H 8/9卫星资料的相关性明显高于FY-4A。对于不同量级降水,5 min降水量越大,降水云的红外和水汽通道亮温越低,水汽与红外通道亮温差也更接近0 ℃,5 min降水量大于10 mm的强降水云集中分布在红外通道亮温低于-40 ℃、水汽与红外通道亮温差在-5~2 ℃的区域。对于同一量级降水,冷涡降水云的红外通道亮温和水汽通道亮温低于副热带高压边缘降水云,水汽与红外通道亮温差也更加接近。冷涡降水云常发生在强静力不稳定、强垂直风切变且更干冷的环境下,由于低层温度露点差较大,云底以下的蒸发作用对降水的削弱更明显,因此对于相同降水强度的降水云,冷涡降水云的红外通道亮温要比副热带高压降水云低。

       

      Abstract: Four precipitation processes in the Liaoning Province under the background of the Cold Vortex and Subtropical High were analyzed,and the correlation between the infrared channel brightness temperature(center wavelength around 12.0 μm) and water vapor channel brightness temperature(center wavelength around 7.0 μm) of the FY-4B,ERA5 reanalysis,and automatic weather station data of the stationary meteorological satellites FY-4A,FY-4B,and H8/9(respectively referred to as FY-4B,FY-4B,and H8/9) was explored.Moreover,the observation characteristics and formation mechanism of precipitation clouds under different weather systems were compared and analyzed based on FY-4B,ERA5 reanalysis,and automatic weather station data.The analysis results are shown as follows.The correlation coefficient between FY-4B and H8/9 satellite data is significantly higher than that of FY-4A.For different levels of precipitation,the larger the 5-minute precipitation,the lower the brightness temperature of the infrared and water vapor channels of precipitation clouds,and the temperature difference between water vapor and infrared channels is also closer to 0 ℃.The infrared channel brightness temperature of strong precipitation clouds with a 5-minute rainfall greater than 10 mm are concentrated in below -40 ℃,and the temperature difference between water vapor and infrared channels of the strong precipitation clouds is within the range of -5 to 2 ℃.For precipitation of the same magnitude,the infrared channel brightness and water vapor channel brightness temperature of precipitation clouds under the influence of Cold Vortex are lower than those of precipitation clouds at the edge of the Subtropical High,and the temperature difference between water vapor and infrared channel brightness is also closer.Precipitation clouds of Cold Vortex generally appear in environments with strong static instability,strong vertical wind shear,and more dry and cold conditions.Due to the large difference in dew-point temperature at lower levels,the evaporation below the cloud base weakens precipitation more significantly.Therefore,for precipitation clouds with the same precipitation intensity,the infrared channel brightness temperature of precipitation clouds under Cold Vortex is lower than that of Subtropical High precipitation clouds.This research provides a reference for strengthening the comprehensive application of satellite data and improving rainstorm monitoring capability in the future.

       

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