A comparison of TWP-ICE observational data with cloud-resolving model results

Authors

A. M. Fridlind, NASA Goddard Institute for Space Studies
A. S. Acherman, NASA Goddard Institute for Space Studies
J. -P Chaboureau, University of Toulouse/CNRS
J. Fan, Atmospheric Sciences and Global Change Division,
W. W. Grabowski, Mesoscale and Microscale Meteorology, National Center for Atmospheric Research, Boulder, Colorado
A. A. Hill, Met Office, Exeter, UK
T. R. Jones, Colorado State University - Fort Collins
M. M. Khaiyer, Science Systems, and Applications, Inc.,
G. Liu, Florida State University
P. Minnis, NASA Langley Research Center
H. Morrison, Mesoscale and Microscale Meteorology, National Center for Atmospheric Research, Boulder, Colorado
L. Nguyen, NASA Langley Research Center
S. Park, Iowa State University, University of Nebraska, Lincoln
J. C. Petch, Met Office, Exeter, UK
J. -P. Pinty, University of Toulouse/CNRS
C. Schumacher, Texas A&M University
B. J. Shipway, Met Office, Exeter, UK
A. C. Varble, University of Utah
X. Wu, Florida State University
S. Xie, Lawrence Livermore National Laboratory
M. Zhang, State University of New York at Stony Brook

Date of this Version

2012

Citation

Fridlind, A. M., et al. (2012), A comparison of TWP-ICE observational data with cloud-resolving model results, J. Geophys. Res., 117, D05204, doi:10.1029/2011JD016595.

Comments

This article is a U.S. government work, and is not subject to copyright in the United States.

Abstract

Observations made during the TWP-ICE campaign are used to drive and evaluate thirteen cloud-resolving model simulations with periodic lateral boundary conditions. The simulations employ 2D and 3D dynamics, one- and two-moment microphysics, several variations on large-scale forcing, and the use of observationally derived aerosol properties to prognose droplet numbers. When domain means are averaged over a 6-day active monsoon period, all simulations reproduce observed surface precipitation rate but not its structural distribution. Simulated fractional areas covered by convective and stratiform rain are uncorrelated with one another, and are both variably overpredicted by up to a factor of ~2. Stratiform area fractions are strongly anticorrelated with outgoing longwave radiation (OLR) but are negligibly correlated with ice water path (IWP), indicating that ice spatial distribution controls OLR more than mean IWP. Overpredictions of OLR tend to be accompanied by underpredictions of reflected shortwave radiation (RSR). When there are two simulations differing only in microphysics scheme or large-scale forcing, the one with smaller stratiform area tends to exhibit greater OLR and lesser RSR by similar amounts. After ~10 days, simulations reach a suppressed monsoon period with a wide range of mean precipitable water vapor, attributable in part to varying overprediction of cloud-modulated radiative flux divergence compared with observationally derived values. Differences across the simulation ensemble arise from multiple sources, including dynamics, microphysics, and radiation treatments. Close agreement of spatial and temporal averages with observations may not be expected, but the wide spreads of predicted stratiform fraction and anticorrelated OLR indicate a need for more rigorous observation-based evaluation of the underlying micro- and macrophysical properties of convective and stratiform structures.