WRF evaluation exercise using open sea in situ measurements

Abstract

This work regards a model evaluation exercise concerning the WRF meteorological model and in situ measurements collected both over land, at four WMO meteorological stations, and over open sea, by ODAS Italia 1, the only spar buoy in the Mediterranean Sea. In particular, this exercise is finalised to understand the ability of the model to act as meteorological pre-processor to simulate aerosol emissions from the sea, an important factor to correctly predict pollutant levels. The test is carried out for the August to December 2005 period over the Ligurian Sea region, a very complex area where the strong air-sea interactions and orography significantly affect the atmospheric circulation. Performances of two model versions, WRF-ARW 3.0 and WRF-ARW 3.2.1, applied at two different horizontal resolutions, have been compared. The results show that the new parameterisations introduced in WRF 3.2.1 improve the performance of the model with respect to version 3.2.0. Increasing the model domain resolution from 15 km to 5 km does not generally improve the model performance, except for the wind direction reconstruction. The model proved its reliability as meteorological processor, although further efforts are required to improve wind field simulation, mainly in order to reduce the low bias still affecting the reconstruction at high wind speed.