Sensitivity of a mesoscale model to initial specification of relative humidity, liquid water and vertical motionThe influence of synoptic scale initial conditions on the accuracy of mesoscale precipitation modeling is investigated. Attention is focused on the relative importance of the water vapor, cloud water, rain water, and vertical motion, with the analysis carried out using the Limited Area Mesoscale Prediction System (LAMPS). The fully moist primitive equation model has 15 levels and a terrain-following sigma coordinate system. A K-theory approach was implemented to model the planetary boundary layer. A total of 15 sensitivity simulations were run to investigate the effects of the synoptic initial conditions of the four atmospheric variables. The absence of synoptic cloud and rain water amounts in the initialization caused a 2 hr delay in the onset of precipitation. The delay was increased if synoptic-scale vertical motion was used instead of mesoscale values. Both the delays and a choice of a smoothed moisture field resulted in underestimations of the total rainfall.
Document ID
19870024474
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Kalb, M. W. (NASA Marshall Space Flight Center; Universities Space Research Association, Huntsville, AL, United States)
Perkey, D. J. (Drexel University Philadelphia, PA, United States)