Interannual variability of Mediterranean evaporation and its relation to regional climate
2012 (English)In: Climate Dynamics, ISSN 0930-7575, E-ISSN 1432-0894, Vol. 38, no 3-4, 495-512 p.Article in journal (Refereed) Published
Gridded monthly evaporation data for 1958-2006 from the Woods Hole Oceanographic Institution data set are used to investigate interannual variability of Mediterranean evaporation during cold and hot seasons and its relation to regional atmospheric dynamics, sea surface temperature and atmospheric elements of the hydrological cycle. The first EOF mode of Mediterranean evaporation, explaining more than 50% of its total variance, is characterized by the monopole pattern both in winter and summer. However, despite structural similarity, the EOF-1 of Mediterranean evaporation is affected by different climate signals in cold and hot seasons. During winter the EOF-1 is associated with the East Atlantic teleconnection pattern. In summer, there is indication of tropical influence on the EOF-1 of Mediterranean evaporation (presumably from Asian monsoon). Both in winter and summer, principal components of EOF-1 demonstrate clear interdecadal signals (with a stronger signature in summer) associated with large sea surface temperature anomalies. The results of a sensitivity analysis suggest that in winter both the meridional wind and the vertical gradient of saturation specific humidity (GSSH) near the sea surface contribute to the interdecadal evaporation signal. In summer, however, it is likely that the signal is more related to GSSH. Our analysis did not reveal significant links between the Mediterranean evaporation and the North Atlantic Oscillation in any season. The EOF-2 of evaporation accounts for 20% (11%) of its total variance in winter (in summer). Both in winter and summer the EOF-2 is characterized by a zonal dipole with opposite variations of evaporation in western and eastern parts of the Mediterranean Sea. This mode is associated presumably with smaller scale (i.e., local) effects of atmospheric dynamics. Seasonality of the leading modes of the Mediterranean evaporation is also clearly seen in the character of their links to atmospheric elements of the regional hydrological cycle. In particular, significant links to precipitation in some regions have been found in winter, but not in summer.
Place, publisher, year, edition, pages
2012. Vol. 38, no 3-4, 495-512 p.
Regional hydrological cycle, Interannual climate variability, Seasonality, Evaporation, Mediterranean Sea
Meteorology and Atmospheric Sciences
IdentifiersURN: urn:nbn:se:su:diva-76310DOI: 10.1007/s00382-011-1218-7ISI: 000299899300004OAI: oai:DiVA.org:su-76310DiVA: diva2:526917