Joint Seminar: Use of simulated CloudSat/CALIPSO data to evaluate numerical models

CloudSat radar reflectivities are simulated in the Met Office global forecast model in a manner which is consistent with the CloudSat observations. The method is described and applied in an evaluation study of the model's performance over the period December 2006 to February 2007. The study uses both statistical and case study approaches and examines the model's simulation of cloud systems globally and in three regions of contrasting weather and cloud regimes: the tropical warm pool, the north Atlantic Ocean and the stratocumulus region off the west coast of California. In general, the model shows a good represention of the vertical structure of clouds systems, although a lack of mid-level cloud is ubiquitous. The model shows a non-drizzling cloud mode and a clearly separated drizzling mode that is not seen in the observations, independent of the geographical region. The comparisons suggest that the intensity of drizzle is too high, confirming on a global basis what recent ground-based measurements have also shown. They also suggest that the parametrization of ice cloud fraction as a monotonic function of the grid-box mean ice water content is not consistent with the observations. The last part of the talk will be dedicated to present the CFMIP ISCCP/CloudSat/CALIPSO simulator (CICCS). CICCS is a colaboration effort that aims to facilitate the exploitation of CloudSat, CALIPSO and ISCCP data in numerical models. It is a system that allows to simulate the signal that CloudSat/CALIPSO/ISCCP would see in a model-generated world. An overview of the on-going work with CICCS will be presented.




13:30 Uhr


Bundesstr. 53, room 022/023
Seminar Room 022/023, Ground Floor, Bundesstrasse 53, 20146 Hamburg, Hamburg


A. Bodas-Salcedo, MetOffice


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