Numerical simulation of a deep Mediterranean storm and its sensitivity on sea surface temperature

Abstract. The development and evolution of a deep low-pressure system over the Eastern Mediterranean has been investigated in comparative numerical experiments with a limited area model using climatological, gridded analyses, satellite-derived and high-resolution re-analysis sea surface temperatures (SSTs) as lower boundary conditions. The severe event of 21–22 January 2004 was selected in view of its strength and considerable impact on the coastal communities of the Northern Aegean Sea. The aim of this study is to investigate the sensitivity of storm development and intensity to the different SST sources. High resolution model simulations were performed resolving mesoscale features modulated by the different source of SSTs. Although the atmospheric response was considerable in terms of rain bands and surface fluxes, the general structure of the system was not significantly affected by the different air-sea interaction forcing. The impact on the model performance (and therefore its forecasting skill) was further assessed on the basis of quantitative verification statistics estimated throughout the period of the simulations. The methodology was based on the verification against surface observations from the World Meteorological Organization network, covering Southern Greece and the coastal areas of Western Turkey. The estimated statistical scores revealed small but noticeable deviations among the forecast skills of the simulations.