Extended Abstract (208K)11.5
Results of using the PSU shallow convection scheme in an ensemble mode: Effects on mass flux profiles and thermodynamic tendencies
Ricardo C. Muņoz, Penn State Univ., University Park, PA; and N. L. Seaman, D. R. Stauffer, and A. Deng
The PSU shallow convection scheme, originally developed with a single cloud size, has been extended to consider an ensemble of clouds by varying the properties of the cloud initiating parcels according to a given distribution. This extension has required among other things revisions to the standard Kain-Fritsch updraft algorithm to ensure smooth behavior for continuous variations in the properties of its initiating parcel. In this paper we describe the modifications made to the shallow cloud scheme and show results from one-dimensional applications for a BOMEX initial profile. The focus of the study is on the effects that the ensemble of clouds, generated through a distribution of thermodynamic perturbations in the boundary layer, has on the shape of entrainment/detrainment and total mass flux profiles and thermodynamic tendencies. Preliminary results obtained with the new scheme are shown to have more realistic profiles, as demonstrated by observations and LES results for trade-wind cases. Sensitivities of the results to the probability distribution assumptions and other parameters are also presented.
Session 11, Ensembles
Thursday, 15 August 2002, 10:30 AM-12:00 PM
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