The Influence of the Formulation of Parameterized Convective Processes on Global Climate Model Simulations of the West African Monsoon
Abstract
This study examines the influence of the parameterizations of subgrid-scale convective processes on the capability of a subset the latest generation of global climate models to simulate seasonal rainfall and the associated thermodynamic and radiative environment observed in the West African Monsoon. A single column of grid-scale output from an emissions scenario experiment for two coupled models is compared to the observed evolution of rainfall, surface meteorology, the thermodynamic state of the atmosphere, clouds and radiation measured during 2006 in Niamey, Niger using the Atmospheric Radiation Measurement Mobile Facility #1. Results confirm that deficiencies in subgrid-scale physics can be a significant source of error with regards to the timing of simulated rainfall at seasonal scales and, in some models these deficiencies may dominate non-local sources of error. Comparison of the performance of each model and their respective convective parameterizations indicates that the capability to simulate the seasonal cycle of rainfall in the Sahel with realistic timing appears to be more sensitive to a realistic representation of convective precipitation microphysics than to a realistic representation of the organization of convective structures. The study sheds a positive light on the present capabilities of coupled models to simulate convection in the Sahel and suggests that resolution of the long-standing disagreement in rainfall projections among different coupled models may be more within reach than previously thought.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.A21H2251T
- Keywords:
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- 3311 Clouds and aerosols;
- ATMOSPHERIC PROCESSES