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中国物理学会期刊

1907号台风“韦帕”登陆期间眼壁区的垂直电场探空观测

CSTR: 32037.14.aps.70.20202183

Sounding observation of vertical electric field in eyewall of Typhoon Wipha (No. 1907) during landing period

CSTR: 32037.14.aps.70.20202183
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  • 2019年夏季在海南文昌获取到1907号台风“韦帕”眼壁内的一次电场探空资料, 本文利用卫星、雷达、地面电场及海南省地闪定位资料对该台风特征进行详细分析, 在此基础上, 对探空路径区域内的电场廓线以及电荷区分布进行了分析, 结果显示: 在海拔高度5.74—9.10 km之间共有4个正电荷区和3个负电荷区, 这7个电荷区所处的温度区间在–2.4— –16.7 ℃之间, 自下而上各电荷区的平均电荷密度分别为0.63, –0.33, 0.31, –1.03, 1.70, 1.57和–1.20 nC/m3, 初步分析认为最上部的两个正电荷区应该为同一个电荷区, 由此在综合考虑电荷区厚度的情况下, 发现强度最大的三个电荷区分别为最下部的正电荷区、中部的主负电荷区与上部的主正电荷区, 三者呈三极性电荷结构特征, 其次为云上边界厚度较薄的负极性屏蔽电荷层, 下部正电荷区与主负电荷区之间的两个电荷区最弱.

     

    In the summer of 2019, one case of electric field sounding in eyewall of No.1907 typhoon named Wipha was obtained in Wenchang, Hainan Island, China. Up to now, it has been the first case of electric field sounding results obtained in a typhoon system. In this paper, based on the observations of satellite, meteorological radar, ground electric field and cloud-to-ground flash location data of Hainan province, China, the basic characteristics of the typhoon are analyzed in detail. Owing to the limitation of cloud-to-ground flash location system, only flash activities of the typhoon before and after landing period are analyzed and the result does not show obvious features as reported by other researches. Referring to the radar reflectivity and sounding path, we confirm that the sounding penetrates through the eyewall region of the typhoon from cloud base to top. The electric field profile and the charge region distribution in the sounding path area are analyzed, and the results show that four positive and three negative charge regions exist between 5.74 and 9.10 km above sea level and the corresponding temperatures range from –2.4 to –16.7 ℃ of the seven charge regions. The mean charge densities of each charge region from bottom to top are 0.63 nC/m3, –0.33 nC/m3, 0.31 nC/m3, –1.03 nC/m3, 1.70 nC/m3, 1.57 nC/m3 and –1.20 nC/m3, respectively. According to the preliminary analysis, we consider that the two positive charge layers at the top should be in the same charge region. Under the comprehensive consideration of the thickness of charge regions, the intensities of these six charge regions are 0.33 nC/m2, –0.07 nC/m2, 0.06 nC/m2, –0.87 nC/m2, 0.73 nC/m2, and –0.18 nC/m2, respectively. We can find that there are three dominant charge regions with largest intensity and they are the lowest positive charge region, the middle main negative region, and upper main positive charge region. And these vertical distributions of the three dominant charge regions are characterized by a tripole charge structure. These results are basically consistent with some simulation results. In addition, a negative screen charge region with a shallow depth in a range of 15–20 dBZ of the upper cloud boundary can be found. Combining the popular charging mechanisms, the similarity of tripole charge structure between our sounding and normal thunderstorm are discussed, and we preliminary consider that the non-inductive charging mechanism and the inductive charging mechanism, which originate from normal convection, are also suitable for eyewall region of typhoon.

     

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