A Simple Analysis/Diagnosis System for Real Time Evaluation of Vertical Motion.

摘要

Operational forecasters have realized for many years the importance of vertical motion in determining the birth and decay of weather systems. Qualitative or quasi-quantitative determination of vertical motion from synoptic reasoning is familiar to all operational forecasters. Consideration of vorticity advection,temperature advection,divergence and convergence,differential heating,and orographic effects have long been used by the forecaster as aids in producing precipitation forecasts. A diagnostic vertical motion model using a simple,modified Cressman objective analysis technique and a new 'one-level'version of the quasi-geostrophic omega equation is investigated. The program is designed to run on an AFOS-type minicomputer. The diagnosed vertical motion field is compared with satellite and precipitation data. The results are in good agreement with the observed data,except in data-poor areas and for weak,small-scale systems. Some applications of this technique to operational forecasting are discussed.