Comparison of ARM Cloud Property Observations with CRM Simulations
Xu, K.-M. (a), Cederwall, R.T. (b), Xie, S.C. (b), and Yio, J.J. (b), NASA Langley Research Center (a), Lawrence Livermore National Laboratory (b)
Eleventh Atmospheric Radiation Measurement (ARM) Science Team Meeting
The cloud property observations are compared with cloud-resolving model simulated cloud properties in this study, using the Summer 1997 Intensive Observation Period (IOP) data of the ARM program. Midlatitude continental cumulus convection are simulated by seven 2-D and two 3-D cloud resolving models (CRMs), driven by observed large-scale advective temperature and moisture tendencies, surface turbulence fluxes, and radiative heating profiles during three subperiods of the Summer 1997 IOP. Each subperiod includes two or three precipitation events of various intensities over a span of 4 or 5 days. The observed cloud properties obtained by the ARM Cloud Property Working Group include cloud liquid water path, column cloud fractions and hydrometeor fraction profiles, which are useful for identifying some model deficiencies. Cloud mass fluxes, cloud water mixing ratios and hydrometeor fractions produced by all CRMs are consistent with each other. All CRMs produce large downdraft mass fluxes with magnitudes similar to those of updrafts, in contrast with CRM results for tropical convection. Some intermodel differences in cloud properties are likely to be related to those in the parameterizations of microphysical processes. Uncertainties in diagnosing the mass fluxes will also be discussed using the results from UCLA/CSU CRM. Some comparison with single-column model (SCM) results will also be made, hoping to narrow down the differences among SCMs.
Note: This is the poster abstract presented at the meeting; an extended version was not provided by the author(s).
