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Reconciling Differences Between Large‐Eddy Simulations and Doppler Lidar Observations of Continental Shallow Cumulus Cloud‐Base Vertical Velocity
Author(s) -
Endo Satoshi,
Zhang Damao,
Vogelmann Andrew M.,
Kollias Pavlos,
Lamer Katia,
Oue Mariko,
Xiao Heng,
Gustafson William I.,
Romps David M.
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl084893
Subject(s) - buoyancy , geology , lidar , large eddy simulation , convection , doppler effect , meteorology , cloud base , atmospheric sciences , vertical velocity , cloud computing , mechanics , physics , remote sensing , turbulence , astronomy , computer science , operating system
We investigate a significant model‐observation difference found between cloud‐base vertical velocity for continental shallow cumulus simulated using large‐eddy simulations (LES) and observed by Doppler lidar measurements over the U.S. Southern Great Plains Atmospheric Radiation Measurement Facility. The LES cloud‐base vertical velocity is dominated by updrafts that are consistent with a general picture for convective clouds but is inconsistent with Doppler lidar observations that also show the presence of considerable downdrafts. The underestimation of simulated downdrafts is found to be a robust feature, being insensitive to various numerical, physical, or dynamical choices. We find that simulations can more closely reproduce observations only after improving the model physics to use size‐resolved microphysics and horizontal longwave radiation, both of which modify the cloud buoyancy and velocity structure near cloud side edges. The results suggest that treatments that capture these structures are needed for the proper simulation and subsequent parameterization development of shallow cumulus vertical transport.