TY - JOUR
T1 - Cloud-Resolving Model Intercomparison of an MC3E Squall Line Case
T2 - Part II. Stratiform Precipitation Properties
AU - Han, Bin
AU - Fan, Jiwen
AU - Varble, Adam
AU - Morrison, Hugh
AU - Williams, Christopher R.
AU - Chen, Baojun
AU - Dong, Xiquan
AU - Giangrande, Scott E.
AU - Khain, Alexander
AU - Mansell, Edward
AU - Milbrandt, Jason A.
AU - Shpund, Jacob
AU - Thompson, Gregory
N1 - Publisher Copyright:
©2019. The Authors.
PY - 2019/1/27
Y1 - 2019/1/27
N2 - In this second part of a cloud microphysics scheme intercomparison study, we focus on biases and variabilities of stratiform precipitation properties for a midlatitude squall line event simulated with a cloud-resolving model implemented with eight cloud microphysics schemes. Most of the microphysics schemes underestimate total stratiform precipitation, mainly due to underestimation of stratiform precipitation area. All schemes underestimate the frequency of moderate stratiform rain rates (2–6 mm/hr), which may result from low-biased ice number and mass concentrations for 0.2–2-mm diameter particles in the stratiform ice region. Most simulations overestimate ice water content (IWC) at altitudes above 7 km for temperatures colder than −20 °C but produce a decrease of IWC approaching the melting level, which is opposite to the trend shown by in situ observations. This leads to general underestimations of stratiform IWC below 5-km altitude and rainwater content above 1-km altitude for a given rain rate. Stratiform precipitation area positively correlates with the convective condensate detrainment flux but is modulated by hydrometeor type, size, and fall speed. Stratiform precipitation area also changes by up to 17%–25% through alterations of the lateral boundary condition forcing frequency. Stratiform precipitation, rain rate, and area across the simulations vary by a factor of 1.5. This large variability is primarily a result of variability in the stratiform downward ice mass flux, which is highly correlated with convective condensate horizontal detrainment strength. The variability of simulated local microphysical processes in the stratiform region plays a secondary role in explaining variability in simulated stratiform rainfall properties.
AB - In this second part of a cloud microphysics scheme intercomparison study, we focus on biases and variabilities of stratiform precipitation properties for a midlatitude squall line event simulated with a cloud-resolving model implemented with eight cloud microphysics schemes. Most of the microphysics schemes underestimate total stratiform precipitation, mainly due to underestimation of stratiform precipitation area. All schemes underestimate the frequency of moderate stratiform rain rates (2–6 mm/hr), which may result from low-biased ice number and mass concentrations for 0.2–2-mm diameter particles in the stratiform ice region. Most simulations overestimate ice water content (IWC) at altitudes above 7 km for temperatures colder than −20 °C but produce a decrease of IWC approaching the melting level, which is opposite to the trend shown by in situ observations. This leads to general underestimations of stratiform IWC below 5-km altitude and rainwater content above 1-km altitude for a given rain rate. Stratiform precipitation area positively correlates with the convective condensate detrainment flux but is modulated by hydrometeor type, size, and fall speed. Stratiform precipitation area also changes by up to 17%–25% through alterations of the lateral boundary condition forcing frequency. Stratiform precipitation, rain rate, and area across the simulations vary by a factor of 1.5. This large variability is primarily a result of variability in the stratiform downward ice mass flux, which is highly correlated with convective condensate horizontal detrainment strength. The variability of simulated local microphysical processes in the stratiform region plays a secondary role in explaining variability in simulated stratiform rainfall properties.
KW - microphysics parameterization
KW - model intercomparison
KW - squall line
KW - stratiform precipitation
UR - http://www.scopus.com/inward/record.url?scp=85060791960&partnerID=8YFLogxK
U2 - 10.1029/2018JD029596
DO - 10.1029/2018JD029596
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AN - SCOPUS:85060791960
SN - 2169-897X
VL - 124
SP - 1090
EP - 1117
JO - Journal of Geophysical Research: Atmospheres
JF - Journal of Geophysical Research: Atmospheres
IS - 2
ER -