Verificação das previsões de tempo para precipitação usando ensemble regional para o estado do Ceará em 2009

Abstract

This work presents a verification study of rainfall forecast by a regional model ensemble prediction system. The ensemble is formed by six members; four of them using RAMS 6.0, and two using WRF 3.1, all initialized by CPTEC or GFS general circulation model data and making use of different convection parameterizations. The verification focuses on rainfall forecasts for 24, 48 and 72 hours and rainfall thresholds of 1 mm, 5 mm and 10 mm over the Ceará State. All ensemble members have better skill than persistence in the entire verification domain. RAMS shows a larger accuracy, especially at the northern coast of Ceará, but gives also a larger false alarm ratio than WRF model. The quality of the rainfall forecasts system decreases as either, the rainfall intensity or the forecast horizon time increase.