Thursday, 27 January 2011
Washington State Convention Center
For convective regions of mesoscale convective systems (MCSs) the heating profile has warming at all levels with a maximum at midlevels, whereas in stratiform regions there is a warming peak in the upper troposphere and a cooling peak at low levels (Houze 1982; Johnson and Young 1983). The resulting MCS heating profile is positive at all levels, but with a maximum value in the upper troposphere. Hartmann et al. (1984) demonstrated with a simple linear global model that the top-heavy heat source produces a Walker circulation, which is in much better agreement with observations than those that are produced with a more conventional heat source having a maximum value in the middle troposphere. Recently, Schumacher et al. (2004) showed that the horizontal variation of the vertical distribution of heating, controlled by the horizontal variation of stratiform rain fraction [as obtained from TRMM PR data by Schumacher and Houze (2003)], is also very important in simulating the large-scale tropical circulation correctly. Schumacher et al. (2004) did take into account the effect of shallow as well as deep convection, but they did not fully take into account the variation of height of the profile from region to region. By utilizing the information about precipitation profiles, the spectral latent heating (SLH) algorithm (Shige, Takayabu et al. 2004, 2007) retrieves differences in the shape of convective heating profile between the eastern Pacific and the western Pacific. The differences in the shape of convective heating profiles across the Pacific could have an important effect on the tropical circulation. In this study, the large-scale response of tropical atmosphere to SLH-estimated latent heating is examined, using a global circulation model. Preliminarily results will be shown at the Symposium.
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