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Convection in high stratiform cloud bands, some numerical experiments
Author(s) -
Ryan Brian F.,
Tripoli Gregory J.,
Cotton William R.
Publication year - 1990
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.49711649408
Subject(s) - squall line , radiative transfer , convection , radiative cooling , cloud base , meteorology , geology , atmospheric sciences , evaporative cooler , cloud computing , environmental science , cloud physics , cloud top , mechanics , physics , optics , computer science , operating system
The Colorado State University Regional Atmospheric Modelling System is used to test the hypothesis that unstable convection might be initiated by virga settling from the stratiform region of the conveyor belt into the pre‐frontal airmass below. Both three‐dimensional and two‐dimensional numerical experiments show that evaporative cooling at cloud base and evaporative and radiative cooling at cloud top play important roles in the initiation and organization of high‐based squall lines. However, the formation of virga is neither a necessary nor a sufficient condition for these squall lines. Sensitivity experiments reveal that the simulated squall‐line circulation is mildly sensitive to the size of raindrops assumed to settle from the cloud layer. the circulation, however, is a great deal more responsive to the destabilization caused by cloud‐top radiative cooling.