Meteorological Analysis Systems in North-East Spain: Validation of SAFRAN and SPAN

Abstract

We present an application and validation of the SAFRAN meteorological analysis system for north-east Spain. SAFRAN is also compared to the SPAN analysis system and the meteorological model HIRLAM-HNR, both operational at AEMET. This application of SAFRAN is intended for hydrological studies. This is the first study that shows an application of SAFRAN outside of France and that compares it with SPAN. This is also the first article validating SPAN's rainfall values. Using one year of observational data, the results show that both SAFRAN and SPAN have a similar performance, which is also similar to SAFRAN's performance in France. Thus, SAFRAN and SPAN are both good tools to force land surface models at high resolution in the area of SAFRAN works under the assumption of the existence of climatically homogeneous zones. Two different sets of zones were tested, one based on the AEMET meteorological warning zones and another one based on hydrological catchments. Better results were obtained when using meteor-ological warning zones. However, the difference is small. In north-east Spain, SAFRAN has the same limitations that were previously shown in France: the spatial structure of the fields is not realistic enough and wind speed is underestimated. As expected, both SAFRAN and SPAN work better in flat areas than over areas of steep relief. This can be a problem in hydrological studies, especially for the Ebro river basin, where most of the runoff is generated in the Pyrenees.

Keywords: meteorological analysis, high resolution grid, optimal interpolation, SAFRAN, SPAN, HIRLAM