Decadal change in the sea level pressure prediction skill over the Mediterranean region and its contribution to downstream surface air temperature prediction

Abstract

The Mediterranean region is located over the entrance of the Asian upper level jet. The anomalous atmospheric circulation over the region can excite wave train pattern propagating eastward and impacting the climate over the Eurasian continent. In this study, the summer (June–September) sea level pressure (SLP) prediction skill over the Mediterranean region is investigated, based on the May-start hindcasts of five state-of-the-art coupled models from the ENSEMBLES over the period of 1960–2005. The result shows that there are three models that exhibit an increased prediction skill for the Mediterranean SLP after the late 1970s. Tropical sea surface temperature (SST) is generally recognized as the major source for dynamical seasonal climate prediction. The analysis of the three models shows that they can capture well the observed impact of tropical Atlantic and Pacific SSTs on the Mediterranean atmospheric circulation after the late 1970s. Consequently, the three models have an increased prediction skill for the Mediterranean SLP over the time. In contrast, the other two models cannot reproduce the observed relationship of the Mediterranean SLP with the tropical Atlantic and Pacific SSTs, thereby exhibiting low prediction skill for the Mediterranean SLP. Further analysis indicates that the increased prediction of the Mediterranean SLP can improve dynamical prediction of surface air temperature (SAT) over the eastern Mediterranean and central East Asia, which is valuable for current regional dynamical seasonal climate prediction.