A computational study of the relationships linking lightning frequency and other thundercloud parameters

摘要: In an effort to optimize the value of global-scale measurements obtained with NASA/MSFC satelliteborne Lightning Imaging System (LIS), a simple computational model thundercloud electrification has been developed, from which it is possible derive crude relationships between lightning frequency f (which LIS will measure) and cloud parameters such as radar reflectivity Z, precipitation rate P, updraught speed w, radius R, ice-crystal concentration i graupel-pellet Ng. Electric field-growth assumed occur via non-inductive charging mechanism, for both Fletcher Hallett-Mossop types glaciation mechanisms. A criterion used distinguish cloud-to-ground intracloud discharges. found be especially sensitive w in situations where, increases, temperature at balance level, Tbal, upper boundary zone falls. these circumstances N1 sizes ice hydrometeors are significantly increased, corresponding enhancement effectiveness charge transfer. Over wide range conditions, roughly proportional first power R1NiNg Z (in some circumstances) least sixth w. relationship P depends critically on whether or not Tbal strongly linked. capable producing inverted-polarity thunderclouds; not.