張 宇,陳加清,蘇滿堂,楊 杰(解放軍理工大學氣象海洋學院,雷電防護與電子偽裝實驗室,南京,210000)
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Meso-nh起電參數化方案研究進展
張 宇,陳加清,蘇滿堂,楊 杰
(解放軍理工大學氣象海洋學院,雷電防護與電子偽裝實驗室,南京,210000)
摘要:大量的試驗結果表明,霰或冰晶上的轉移電荷的極性和量級取決于很多因素。這些影響因素包含碰撞粒子的大小、相對降落末速、云溫、液態水含量等,它們都對非感應起電率都有所影響。當在參數化方案中考慮的因素不同時,每次碰撞時所轉移電荷的數量和極性均有所差異。
關鍵詞:雷暴云電荷結構;模擬;Meso-nh
Meso-NH雷電模式包含了先進的感應、非感應起電方案,它將雷電起電、放電機制直接耦合到高分辨率中尺度非靜力平衡模式中,為中尺度天氣-雷電一體化的數值預報模式,可以像預報其它天氣過程(鋒面、臺風、降雨等)一樣,對雷電天氣過程進行數值預報及模擬。它已經實現并行化計算并成功地應用于法國地區雷電天氣的預報。此模式經項目組調試和改造,已經可以應用于我國雷電天氣數值模擬,但有一些參數和方案針對我國各地區還需要做進一步的優化。
電荷轉移量的計算方案為:

Tsenova and Mitzeva (2011) 對上述實驗室給出的非感應起電方案進行了修訂,其中電荷交換公式改為:






當霰粒子和冰晶粒子碰撞時,電荷轉移量計算方案為:

采用不同的非感應起電參數化方案,雷暴生命史中不同時期
的電荷結構分布有所不同。其可能原因是這幾種方案對微物理條件比較敏感,如溫度、有效液態水含量、淞附增長率、粒子尺寸、碰撞粒子的相對速度等。還應該注意的是,雷暴云內的電荷積累及分離有可能是兩種或更多種機制的共同作用結果,所以對于其它可能的起電機制的認識及各種起電機制之間的互相作用也必須給予重視。
參考文獻
[1] Reynolds S E,Brook M,Gourley M F.1957. Thunderstorm charge separation[J].J.Meteor.,14:426-436.
[2] Saunders, C. P. R. and I. Brooks, 1992:The effects of high liquid water content on thunderstorm charging. J. Geophys. Res., 97 (D13), 14 671-14 676.
[3] Helsdon, J. H., G. Wu, and R. D. Farley, 1992: An intracloud lightning parameterization scheme for a storm electrification model. J. Geophys. Res., 97, 5865-5884. [4] Takahashi, T., 1978: Riming electrification as a charge generation mechanism in thunderstorms. J.Atmos. Sci.,35, 1536-1548.
[5] Tsenova, B. and R. Mitzeva, 2011: Comparative modelling study of the effect of parameterizations based on rime accretion rate and on effective water content on simulated charge density in thunderstorms. IDOJARAS,115 (4), 247-263.
Progress in the electrical parameters of the program from the Meso-nh
Zhang Yu,Chen Jiaqing,Su Mantang,Yang Jie
(PLA Univ. of Sci. & Tech., National Key Laboratory of Science and Technology on Electromagnetic Effects and Electro-optical Engineering, Nanjing 211101,China)
Abstract:A large number of experimental results show that the charge transfer sleet or ice on the polarity and magnitude depends on many factors.These factors contain the size of the colliding particles, relative to the end of the landing speed,temperature and cloud liquid water content,etc.,which are non-inductive power rate has affected right.When the factors considered in the parameterization scheme is not the same each time the collision transfer charge amount and polarity were different.
Keywords:Thunderstorm charge structure;simulation;Meso-nh