The skill of ECMWF precipitation and temperature predictions in the Danube basin as forcings of hydrological models.

TitleThe skill of ECMWF precipitation and temperature predictions in the Danube basin as forcings of hydrological models.
Publication TypeMiscellaneous
Year of Publication2008
AuthorsPappenberger, F, Buizza, R
Secondary TitleTechnical Memorandum
Number558
Abstract

In this paper the suitability of ECMWF forecasts for hydrological applications is evaluated. This study focuses on three spatial scales: the upper Danube (which is upstream of Bratislava), the entire Danube catchment and the whole of Europe. Two variables, 2-meter temperature and total precipitation, are analyzed. The analysis shows that precipitation forecasts follow largely in pattern the observations. The timing of peaks between forecasted and observed precipitation and temperature is good although precipitation amounts are often underestimated. Catchment scale influences the skill scores significantly. Small catchments exhibit a larger variance as well as larger extremes. The analysis of the performance of ensemble forecasts show a positive trend of skill scores for the probabilistic prediction of moderate precipitation amounts can be observed towards the end of 2006, following the increase of the ensemble resolution and the implementation of a new convection scheme. A water balance analysis suggests a 10% underestimation by the ensemble mean and an overestimation by the high resolution forecast over the last years. Precipitation and Temperature predictions are skillful up to day 5-7. Forecasts accumulated over a longer time are largely more skillful than forecasts accumulated over short time periods.