Variability of Lightning Activity as a Function of Tropical Easterly Wave Phase
نویسندگان
چکیده
3-5 day Tropical Easterly Waves (TEWs) significantly modulate tropical convection, which in turn influences tropical cyclogenesis. Geostationary satellite imagery provides a robust tool for tracking these disturbances in data sparse regions of the globe; however, the satellite imagery provides little information on TEW convective vertical structurea key parameter in both the understanding and prediction of TEW evolution. Hence we pose the following question: Can lightning data be used to reliably indicate changes in mean convective vertical structure, and as a result, latent heating as a function of easterly wave-phase? To answer this question, we present a combined analysis of ship, space, and ground based radar and lightning data (TRMM-LIS, long range NLDN) for regions of prolific TEW activity (tropical eastern Pacific Ocean and tropical western Africa). By compositing lightning and radar data based on the phase of TEWs at 700 hPa (ridge, northerly, trough and southerly wind phases) we find that the lightning data can be used as a reliable metric of changes in convective vertical structure across different synoptic phases of TEWs. Since changes in convective vertical structure are indicative of related changes in the vertical profiles of cloud mass flux and latent heating, it may be possible to use lightning data to infer changes in latent heating profile across TEWs.
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