32nd Conference on Broadcast Meteorology/31st Conference on Radar Meteorology/Fifth Conference on Coastal Atmospheric and Oceanic Prediction and Processes

Friday, 8 August 2003
Simulated KWAJEX convective systems using a 2D and 3D cloud resolving model and their comparisons with radar observations
Chung-Lin Shie, NASA/GSFC, Greenbelt, MD and Goddard Earth Sciences and Technology Center/UMBC, Baltimore, MD; and W. K. Tao and J. Simpson
Poster PDF (370.1 kB)
The 1999 Kwajalein Atoll field experiment (KWAJEX), one of several major TRMM (Tropical Rainfall Measuring Mission) field experiments, has successfully obtained a wealth of information and observational data on tropical convective systems over the western Central Pacific region. In this paper, clouds and convective systems that developed during three active periods (Aug 7-12, Aug 17-21, and Aug 29-Sep 13) around Kwajalein Atoll site are simulated using both 2D and 3D Goddard Cumulus Ensemble (GCE) models. Based on numerical results, the clouds and cloud systems are generally unorganized and short lived. These features are validated by radar observations that support the model results.

Both the 2D and 3D simulated rainfall amounts and their stratiform contribution as well as the heat, water vapor, and moist static energy budgets are examined for the three convective episodes. Rainfall amounts are quantitatively similar between the 2D and 3D simulations, but the stratiform contribution is considerably larger in 2D. Regardless of the dimension, for all three cases, the large-scale forcing and net condensation are the two major physical processes that account for the evolution of the budgets with surface latent heat flux and net radiation (solar and long-wave radiation) being secondary processes. Quantitative budget differences between 2D and 3D as well as between various episodes will be detailed at the conference. Moreover, simulated radar signatures and Q1/Q2 fields from the three simulations are also compared to each other and with radar and sounding observations.

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