What determines cloud radiative forcing in a cloud resolving model?
Abstract
We show that the cloud radiative forcing in a cloud resolving model run to radiative convective equilibrium is sensitive to the microphysics parameterizations used and not model conditions such as sea surface temperature, domain size, or even the use of a mixed layer ocean in place of fixed SSTs. Using the model's microphysics, we find that the shortwave cloud radiative forcing is larger in magnitude than the longwave cloud radiative forcing - in contrast to observations where they are nearly equal. When we tune the microphysics following the methods of Lopez et al. (2009), we produce a simulated MODIS histogram of optical depths and cloud top temperatures that more closely matches observations over the Tropical West Pacific (compared to the model's base microphysics) as well as a net cloud radiative forcing near zero. Changes to surface conditions do little to alter the net cloud radiative forcing for either of the microphysics choices.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.A54D..03H
- Keywords:
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- 0321 ATMOSPHERIC COMPOSITION AND STRUCTURE Cloud/radiation interaction;
- 3310 ATMOSPHERIC PROCESSES Clouds and cloud feedbacks;
- regional cloud models