The Role of Moist Processes in Response of Shortwave Cloud Radiative Forcing to El Niño Warming
Abstract
The role of moist processes in the climatological mean clouds and the shortwave cloud radiative forcing (SWCF) responses to El Niño warming over the equatorial Pacific, especially the coordination among them, is investigated through two atmospheric model versions, only differing the moist schemes and the uncertain parameters. The results indicate that the stratiform condensation and evaporation play a key role in improving the water vapor (or relative humidity), cloud and in-cloud liquid water path (ICLWP) simulations, reflecting the importance of the cloud macro/micro-physical processes and their coordination with other moist processes, such as the deep and shallow convections. As for the responses, three factors, dynamical, middle cloud and LWP responses, contribute to the diverse SWCF response strengths over the central equatorial Pacific, wherein the strength of the former two responses are consistent with their mean states whereas the weak positive even negative LWP responses are directly linked to the mismatch between ICLWP and cloud in spite of large grid mean LWP, and the eastward high cloud responses in both models are responsible for the shifts of SWCF and longwave cloud radiative forcing (LWCF) responses which is associated with the poor representation of cirrus outflowed from convection in models. Moreover, the different total precipitation responses between two models mainly result from the stratifrom components as its climatology mean state, again suggesting the role of cloud micro/macro-physical processes and the harmonization with other moist processes.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.A21B0008L
- Keywords:
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- 3310 ATMOSPHERIC PROCESSES Clouds and cloud feedbacks