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Importance of microphysical processes in the dynamics of a CSI mesoscale frontal cloud band
Author(s) -
Marecal Virginie,
Lemaitre Yvon
Publication year - 1995
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49712152205
Subject(s) - mesoscale meteorology , evaporation , snow , precipitation , atmosphere (unit) , environmental science , atmospheric sciences , cloud base , meteorology , geology , climatology , cloud computing , physics , computer science , operating system
Microphysical processes in a cloud band observed during the MFDP/F RONTS 87 experiment are studied. The importance of precipitation evaporation in the downdraught zone of the cloud‐band circulation, due to conditional symmetric instability (CSI), is clearly evidenced thanks to a two‐dimensional (2D) microphysical retrieval model applied to an observed 2D wind field. This study shows the crucial role of snow evaporation in maintaining the descent of the CSI circulation in a nearly saturated state. The evaporation creates a cooling which reduces the resistance of the atmosphere to subsiding motions, and thus reinforces the ascending ones. Comparisons with results on the effect of snow evaporation on mesoscale motions obtained by other authors with a one‐dimensional model clearly show the effect of the horizontal wind component.