| 冰雹云降水过程中微波亮温的变化特征 |
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| 引用本文： | 何文英,陈洪滨.冰雹云降水过程中微波亮温的变化特征[J].气象与环境科学,2016,39(1):3-11. |
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| 作者姓名： | 何文英 陈洪滨 |
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| 作者单位： | 中国科学院大气物理研究所中层大气与全球环境探测重点实验室，北京 100029 |
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| 摘 要： | 通过冰雹云模式模拟的一次冰雹云降水过程中降水粒子廓线和微波辐射传输模式结合,分析了冰雹云发展的不同阶段的微物理含量垂直结构变化及其对微波亮温的影响,得到以下几点结论:1)如果微波通道受到降水粒子散射和辐射的共同作用,如降水云早期的85 GHz亮温,成熟期的19 GHz亮温及消散期的37 GHz亮温,由于辐射和散射信息互相抵消,致使亮温随雨强的变化较复杂,这些通道亮温和雨强的相关性明显降低,不宜被用来反演地面雨强。2)根据19 GHz亮温随地面雨强或冰相粒子柱含量的改变,可以大致确定降雨云的不同阶段:在发展阶段,主要是降雨层以上的冰相粒子,尤其霰粒影响19 GHz亮温,致使其亮温与冰相粒子柱含量具有较好的负相关,而与地面雨强相关性较差;在成熟阶段,主要受雨水上层逐渐增加的辐射和冰相粒子散射共同作用,使得19GHz亮温与地面雨强和冰相粒子柱含量的相关性都不太好;在消散阶段,19 GHz亮温主要受较强的雨水辐射影响,与地面雨强和冰相粒子柱含量均有着较高的正相关。3)37 GHz是相对比较稳定的通道,其亮温与地面雨强有较好的线性关系,尤其与冰相粒子柱含量相关性更好,因此是反演地面雨强和冰相粒子柱含量的最佳通道。85 GHz亮温对降雨云体的中高层结构较为敏感,使得其亮温随地面雨强增加而降低的变化比较离散,不如37 GHz的集中。
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| 关 键 词： | 微波亮温 云模式 辐射传输模式 冰雹云降水 |
Variation Characteristics of Microwave Brightness Temperatures During the Evolution of Hailstorm Precipitation |
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| He Wenying,Chen Hongbin.Variation Characteristics of Microwave Brightness Temperatures During the Evolution of Hailstorm Precipitation[J].Meteorological and Environmental Sciences,2016,39(1):3-11. |
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| Authors: | He Wenying Chen Hongbin |
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| Institution: | Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO),Institute of Atmospheric Physics, Chinese Academy of Sciences,Beijing 100029,China |
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| Abstract: | The hydrometeor profiles from convective cloud process are put into a microwave radiative transfer model to investigate the variation characteristics of the microwave brightness temperatures (Tb) for different stages of hailstorm precipitation. Results are as follows.1)When the contributions of scattering and emission radiance from hydrometeors are comparable to one microwave channel, this channel, as 85 GHz Tb at the early stage, 19 GHz at the maturing stage and 37 GHz at the dissipation stage, is not suitable for retrieving surface rainfall because of its poor correlation with precipitation. 2)The variation trends of Tb at 19 GHz with surface rainfall or column ice content can reveal the rainfall developing stages. At the early formation stage of precipitation, 19 GHz Tb is mainly affected by ice particle scattering, resulting in its obvious negative correlation with the ice content. At the storm maturing stage, the emission from liquid water and scattering from ice particle both contribute to 19 GHz Tb, so the Tb rainfall correlations and Tb column ice content correlation are very poor. At the dissipation stage, 19 GHz Tb is mainly determined by the emission of increasing liquid water, leading to its high positive correlation with surface rainfall and column ice content. 3)In addition, 37 GHz is one optimal channel to retrieve surface rainfall and column ice content owing to its stable relationship with them. While 85 GHz Tb is more sensitive to hydrometeors structure above freezing layer so that its correlation with surface rainfall is not as good as 37 GHz. |
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| Keywords: | microwave brightness temperature cloud model radiative transfer model hailstorm precipitation |
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