The eastern Mediterranean teleconnection pattern: identification and definition

摘要

In this study, an attempt is made to investigate possible teleconnection patterns of atmospheric circulation, centered over eastern Mediterranean (EM) with the aid of gridded NCEP/NCAR daily values of geopotential heights for the period 1958-2003. For this purpose, two approaches have been used: correlation analysis and rotated principal component analysis (PCA) on a seasonal and monthly basis. A teleconnection pattern between the EM and northeastern Atlantic was identified at 500 and 300 hPa in winter, which will be referred to as the Eastern Mediterranean Pattern (EMP), appearing as an independent mode of the upper circulation. The pattern also exists in autumn but is substantially weakened with its dipole centers being shifted eastwards. Significant monthly variations were found in the location, strength and structure of the pattern. The employment of a standardized index demonstrated that the negative phase of the EMP prevails throughout the year with the maximum frequency at wintertime. Copyright (c) 2006 Royal Meteorological Society