Drought episodes in the climatological sinks of the Mediterranean moisture source: The role of moisture transport

摘要

It is well known from previous work that the regions most affected by moisture transport from the Mediterranean Sea (MED) are central-eastern Europe and the eastern Mediterranean. We apply a Lagrangian approach to investigate whether severe drought episodes observed in these areas, hereafter referred to as the climatological moisture sinks of the MED source, are associated with changes in moisture transport from the basin. The drought events were identified for both hydrological summer and winter using the Standardised Precipitation Evapotranspiration Index (SPEI). The analyses were complemented with fields of precipitation and potential evapotranspiration (PET) over the sinks, together with evaporation over MED and the vertically integrated moisture flux. According to our results, a significant reduction in the moisture contribution from MED is evident in events for both summer and winter, as evidenced by the values accumulated over the episodes concerned. Anomalies in MED evaporation presented seasonal contrasts, i.e., a reduction in winter and an increase in summer episodes. In terms of interannual variability, linear correlation analyses show that in winter, the SPEI over the sinks is more associated with moisture transport from the MED than with MED evaporation. The correlation between moisture contribution from MED and the sink SPEI/precipitation is stronger in winter than summer. (C) 2016 Elsevier B.V. All rights reserved.