Open AccessAnalysis of cloud‐resolving simulations of a tropical mesoscale convective system observed during TWP‐ICE: Vertical fluxes and draft properties in convective and stratiform regions
Author(s) -
Mrowiec Agnieszka A.,
Rio Catherine,
Fridlind Ann M.,
Ackerman Andrew S.,
Del Genio Anthony D.,
Pauluis Olivier M.,
Varble Adam C.,
Fan Jiwen
Publication year - 2012
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2012jd017759
Subject(s) - graupel , convection , atmospheric sciences , mass flux , environmental science , mesoscale meteorology , precipitation , mesocyclone , mesoscale convective system , ice crystals , wind profiler , free convective layer , meteorology , climatology , geology , mechanics , radar , physics , doppler radar , telecommunications , computer science
We analyze three cloud‐resolving model simulations of a strong convective event observed during the TWP‐ICE campaign, differing in dynamical core, microphysical scheme or both. Based on simulated and observed radar reflectivity, simulations roughly reproduce observed convective and stratiform precipitating areas. To identify the characteristics of convective and stratiform drafts that are difficult to observe but relevant to climate model parameterization, independent vertical wind speed thresholds are calculated to capture 90% of total convective and stratiform updraft and downdraft mass fluxes. Convective updrafts are fairly consistent across simulations (likely owing to fixed large‐scale forcings and surface conditions), except that hydrometeor loadings differ substantially. Convective downdraft and stratiform updraft and downdraft mass fluxes vary notably below the melting level, but share similar vertically uniform draft velocities despite differing hydrometeor loadings. All identified convective and stratiform downdrafts contain precipitation below ∼10 km and nearly all updrafts are cloudy above the melting level. Cold pool properties diverge substantially in a manner that is consistent with convective downdraft mass flux differences below the melting level. Despite differences in hydrometeor loadings and cold pool properties, convective updraft and downdraft mass fluxes are linearly correlated with convective area, the ratio of ice in downdrafts to that in updrafts is ∼0.5 independent of species, and the ratio of downdraft to updraft mass flux is ∼0.5–0.6, which may represent a minimum evaporation efficiency under moist conditions. Hydrometeor loading in stratiform regions is found to be a fraction of hydrometeor loading in convective regions that ranges from ∼10% (graupel) to ∼90% (cloud ice). These findings may lead to improved convection parameterizations.