|Identifying drizzle within marine stratus with W-band radar reflectivity|
Wang, J.; Geerts, B. (2003). Identifying drizzle within marine stratus with W-band radar reflectivity. Atmos. Res. 69(1-2): 1-27
In: Atmospheric Research. Elsevier: Tokyo; Oxford; New York; Amsterdam. ISSN 0169-8095, more
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Airborne cloud radar and cloud microphysical data, collected in summertime stratus clouds offthe Oregon coast, are analyzed to obtain an empirical threshold radar reflectivity above which drizzlecan be expected in warm marine stratus. Such clouds, which are prevalent over the easternsubtropical oceans, have a profound impact on global climate.This study finds that the threshold reflectivity for drizzle is a strong function of height within thecloud layer. Both radar reflectivities and calculated reflectivities (based on measured droplet spectra)indicate that the threshold is most crisply defined in the lower half of the stratus cloud deck. The useof the threshold reflectivity profile to flag drizzle is illustrated by examining the dependency of radarreflectivity on cloud water content. Such dependency is non-existent in marine stratus in general, buta clear relationship emerges when drizzle cases are excluded.