HR: 1330h
AN: A53A-05    [Abstracts]
TI: Marine Stratus Cloud Objects Simulated by a Cloud-Resolving Model and Observed by Earth Observing System Satellite
AU: Luo, Y
EM: yali@nianet.org
AF: National Institute of Aerospace, 144 Research Drive, Hampton, VA 23666 United States
AU: * Xu, K
EM: Kuan-Man.Xu@nasa.gov
AF: NASA Langley Research Center, Mail Stop 420, Hampton, VA 23681 United States
AB: Using a new approach proposed by Xu et al. (2005), 2162 stratus cloud objects are diagnosed using the Clouds and the Earth's Radiant Energy System (CERES) Single Scanner Footprint (SSF) product on board the Tropical Rainfall Measuring Mission (TRMM) satellite during January-August 1998 at three regions of east Pacific: north subtropical, east equatorial, and south subtropical. A cloud object is identified as a contiguous region of the Earth composed of individual satellite footprints within a single dominant cloud-system type. To be identified as a stratus cloud object, the cloud top height must be less than 3 km and cloud fraction is 0.99-1.00. The probability density functions (PDFs) of several observed and retrieved fields from the CERES SSF product are found to be different among the three regions. Two versions of a cloud-resolving model (CRM), which includes either a two-moment or a one-moment microphysics scheme, are used to simulate a number of the observed marine stratus cloud objects. Number concentrations of cloud droplets and rain drops, in addition to their mixing ratios, are predicted by the CRM version with the two-moment microphysics scheme while they are not predicted by the CRM version with the one-moment microphysics scheme. ECMWF meteorological fields matched with the instantaneous satellite cloud-object data are used to drive the CRM, i.e. to provide initial atmospheric state, large-scale total advective tendencies of temperature and moisture, large-scale horizontal wind speed, and sea surface temperature for the CRM simulations. Detailed analyses of the satellite cloud object data and the CRM simulations will be performed (1) to evaluate the CRM, with focus on how the microphysics schemes influence the simulated cloud properties and cloud radiative forcing, and (2) to understand the physical mechanisms for the differences among the three regions of east Pacific. A bootstrapping technique will be used to identify the statistical differences between the simulated and observed histograms.
DE: 0320 Cloud physics and chemistry
DE: 3307 Boundary layer processes
DE: 3337 Numerical modeling and data assimilation
DE: 3374 Tropical meteorology
SC: Atmospheric Sciences [A]
MN: 2005 Joint Assembly