HR: 09:15h
AN: A31D-06    [Abstracts]
TI: A Satellite Analysis of the Evolution of Tropical Deep Convection, Upper Tropospheric Clouds, and Humidity
AU: * Zelinka, M D
EM: mzelinka@atmos.washington.edu
AF: Department of Atmospheric Sciences University of Washington, Box 351640, Seattle, WA 98195, United States
AU: Hartmann, D L
EM: dennis@atmos.washington.edu
AF: Department of Atmospheric Sciences University of Washington, Box 351640, Seattle, WA 98195, United States
AB: The ability of the Earth to regulate its energy budget is strongly dependent on the concentration of water vapor in the atmosphere. Increases in humidity at upper levels of the troposphere have a greater radiative impact on the climate than equivalent increases closer to the surface. In this study, I investigate the evolution of the moisture and cloud distribution in deep convective systems over the tropical Pacific using retrievals of water vapor, temperature, and cloud properties from AMSR-E, AIRS, and MODIS. Using a compositing technique centered in space and time on locations having high rain rates, I have identified systematic lags in both the fractional coverage of anvil clouds and in the moistening of the upper troposphere following peak convection. Anvil cloud fractions peak 3 hours after the strongest convection while the upper troposphere is most humid 9-15 hours following the strongest convection. Composited vertical velocity profiles from the ERA-40 Reanalysis show anomalous ascent in the upper troposphere following peak convection, which likely has a role in sustaining the moist signature aloft. Correspondingly, clear-sky outgoing longwave radiation remains significantly reduced for several hours after the convection, indicating that the sustained moist anomaly at upper levels continues to affect the local radiation budget well after the convective event.
DE: 0321 Cloud/radiation interaction
DE: 3310 Clouds and cloud feedbacks
DE: 3314 Convective processes
DE: 3360 Remote sensing
DE: 3374 Tropical meteorology
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting