Verification of the vertical motion generation mechanisms in global models and their initial fields in connection with precipitation numerical forecasting

Abstract

Verification of dynamic mechanisms of vertical motion forcing of four global atmosphere's models is performed. A new approach to the verification problem is proposed, which includes: (1) choice of a set of physically substantial criteria of the forecasting efficiency (diagnostic characteristics) of the studied mechanisms, (2) computation of these diagnostic characteristics both from the model output data and from objective analysis used in the models, (3) comparison of the computed values in the forecasting fields, reanalysis data at the forecast time and reanalysis fields obtained from different models, (4) estimation of differences between the compared diagnostics not only on the average over the computation domain, but also over the intervals of their values in the whole range. The proposed approach is applied to reveal reasons of errors in precipitation forecasting in two Russian models (the spectral model of T85L31 of Hydrometeorological Research Center of the Russian Federation and semi-Lagrangian model developed in the Russian Academy of Sciences Institute for Numerical Mathematics in cooperation with Hydrometcenter of Russia, in comparison with the models of the U.K. Met Office (UKMO) and U.S. National Center for Environment Prediction (NCEP).