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郭凤霞, 吴鑫, 梁梦雪, 江涛, 陆干沂. 闪电和固、液态降水关系差异的数值模拟[J]. 大气科学, 2015, 39(6): 1204-1214. DOI: 10.3878/j.issn.1006-9895.1412.14264
引用本文: 郭凤霞, 吴鑫, 梁梦雪, 江涛, 陆干沂. 闪电和固、液态降水关系差异的数值模拟[J]. 大气科学, 2015, 39(6): 1204-1214. DOI: 10.3878/j.issn.1006-9895.1412.14264
GUO Fengxia, WU Xin, LIANG Mengxue, JIANG Tao, LU Ganyi. Numerical Simulation of the Relationships between Lightning and Liquid/Solid Precipitation[J]. Chinese Journal of Atmospheric Sciences, 2015, 39(6): 1204-1214. DOI: 10.3878/j.issn.1006-9895.1412.14264
Citation: GUO Fengxia, WU Xin, LIANG Mengxue, JIANG Tao, LU Ganyi. Numerical Simulation of the Relationships between Lightning and Liquid/Solid Precipitation[J]. Chinese Journal of Atmospheric Sciences, 2015, 39(6): 1204-1214. DOI: 10.3878/j.issn.1006-9895.1412.14264

闪电和固、液态降水关系差异的数值模拟

Numerical Simulation of the Relationships between Lightning and Liquid/Solid Precipitation

  • 摘要: 为了进一步认识闪电和固、液态降水的关系,本文利用三维雷暴云动力-电耦合数值模式,通过设置敏感性试验组,模拟了一次雷暴过程,分析雷暴中闪电和降水的特征,以及闪电和固、液态降水对垂直风速的依赖关系,探讨闪电与固、液态降水的时空分布关系和单次闪电表征的降水量(RPF:rainyields per flash)。结果表明:对流云降水中,液态降水占主要部分,但固态降水比液态降水对于垂直风速的依赖性更强。随着对流的增强,固态降水在总降水中占的比重越来越大。首次放电时间不断提前,闪电峰值落后垂直风速峰值,总闪数一开始随对流的增强而增加,对流一旦增强到一定程度,总闪数则逐渐减小。固态降水和液态降水的开始时间和峰值时间均随着对流的增强而不断提前,而液态降水出现时间和峰值时间均提前于固态降水。雷暴云首次放电的时间滞后于液态降水,而闪电峰值提前固态降水峰值或与固态降水峰值同时产生。雷暴云中的放电活动集中在强降水区域前缘的较弱降水区,强降水区对应的闪电较少,对流的增强会使降水区域面积、降水量和降水强度增加。由于液态降水总量远大于固态降水总量,固、液态RPF的数值相差达到一个量级,但单位时间内固态降水和液态降水增加的速率相近。在单位时间内闪电次数越多,RPF则越小,而固态RPF和闪电次数的线性相关性明显好于液态RPF,所以利用固态降水可以更好地预报闪电。这些结果有助于进一步认识闪电和降水的关系,并可为闪电预报提供新的思路。

     

    Abstract: In order to further understand the differences between lightning and solid/liquid precipitation relationships, a three-dimensional dynamics-electrification coupled model is used to perform sensitivity tests to research the characteristics of lightning and precipitation. The vertical wind upon which lightning and precipitation rely, the spatial and temporal distribution of lightning and solid/liquid precipitation, and rain-yields per flash(RPF) are analyzed in this paper. The results show that the liquid precipitation accounts for the most part of total precipitation, but the solid precipitation is more dependent on vertical wind velocity than liquid precipitation. With the development of convection, the proportion of solid precipitation is increasing. The time of first discharge and the beginning and peak values of liquid and solid precipitation are more advanced. The peak value of lightning lags behind vertical wind and the lightning number first increases then decreases. The liquid precipitation starts before solid precipitation. The first discharge lags behind the beginning of liquid precipitation, but occurs before solid precipitation, or they occur at the same time. The most flashes in the thunderstorms are negative, and the positive and negative leaders' channel projections are located in the slight precipitation area where the leading edge of the heavy precipitation area is. Lightning rarely occurs in the heavy precipitation area. The enhanced convection enlarges the precipitation area and increases the precipitation intensity. Because the amount of liquid precipitation is much more than solid precipitation, there is an order of magnitude difference between the solid RPF and liquid RPF. The growth rates of liquid and solid precipitation are close. The more lightning takes place in unit time, the smaller the RPF is. The relationship between solid precipitation and lightning could be utilized in lightning forecasts, because solid RPF is much more relative to lightning than liquid RPF. The results of this paper offer a further understanding of the relationship between lightning and precipitation, and also suggest a new line of thought regarding lightning forecasts.

     

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