HR: 11:56h
AN: A42C-09    [Abstracts]
TI: A Joint Satellite and Global Cloud-Resolving Model Analysis of the 2006/07 Madden-Julian Oscillation
AU: * Masunaga, H
EM: masunaga@hyarc.nagoya-u.ac.jp
AF: Hydrospheric Atmospheric Research Center, Nagoya University, Furocho Chikusa-ku, Nagoya, 464-8601, Japan
AU: Satoh, M
EM: satoh@ccsr.u-tokyo.ac.jp
AF: Center for Climate System Research, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, 277-8568, Japan
AU: Miura, H
EM: miurah@jamstec.go.jp
AF: Frontier Research Center for Global Change, Japan Agency for Marine-Earth Science and Technology, 3173-25 Showa-machi Kanazawa-ku, Yokohama, 236-0001, Japan
AB: The Madden-Julian Oscillation (MJO) is often considered as a touchstone to test the performance of atmospheric general circulation models (AGCMs). The prescribed parameterization of cumulus convection is likely a major factor that hampers the flexible representation of tropical convection and associated large-scale circulation in AGCMs. The improved treatment of cumulus-scale physics in a way consistent with observations is crucial for further understanding and better model-reproducibility of the MJO. In this study, cloud and precipitation properties associated with the MJO are investigated for 32 days starting from December 15, 2006, based on a joint analysis of global cloud-resolving model simulation and satellite measurements. The model adopted here is the Nonhydrostatic ICosahedral Atmospheric Model (NICAM), where individual convective clouds are explicitly simulated across the entire globe. The simulated cloud/precipitation characteristics are assessed in comparison with satellite observation in the manner described below. Radiative transfer calculations are applied to the NICAM output to simulate 13.8-GHz radar echo and 10.8-μm brightness temperature. The synthesized radar and infrared "observations" are directly comparable with the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) and Visible/Infrared Scanner (VIRS) measurements. The model result exhibits a slow, eastward propagation of convective areas in reasonable agreement with the satellite measurement, although the cloud model tends to excessively produce deep convection. The joint histogram of radar echo-top height and infrared T_b suggests that model-calculated snow may be overly abundant compared to the observation. More analysis focused on large-scale dynamics and the radar sensitivity to microphysics will be presented.
DE: 0320 Cloud physics and chemistry
DE: 0550 Model verification and validation
DE: 6969 Remote sensing
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting