The North-Africa/Western Asia (NAWA) sea level pressure index: A Mediterranean signature of the Northern Annular Mode (NAM)

Abstract

Following work by Paz et al. [2003], the relationship between NAWA and the Eastern Mediterranean (EM) winter climate is explored further. It is found that NAWA can be viewed as the regional signature of the hemispheric northern annular mode (NAM), at all time scales. While in-phase variability of winter NAM and NAWA increased after the so-called climate shift of 1976-77, largest correlation between the two indices is found during January. This is also the month when largest correlations are to be found between NAM and the NAWA poles. Correlations between NAWA and NAM are larger than that between NAWA and the North Atlantic Oscillation (NAO). Further evidence of direct relationship between NAM, NAWA, winter air temperature and rainfall in the EM is given. Copyright 2004 by the American Geophysical Union.