Long-term variations in summer temperatures over the Eastern Mediterranean

Abstract

The inter-annual variation of the 850 hPa temperatures over the Eastern Mediterranean (EM) for July-August was analyzed for 1948-2002, using NCEP/NCAR reanalysis data. The time series of seasonal averages and the distribution of 'hot' and 'cool' days indicate the existence of three distinct warm periods. The warmest began in the mid-1990s. A long-term warming trend of 0.013 Ky-1 was found. The warming trend in July was 7 times greater than that of August, and July replaced August as the warmest month of the year. A trend of increasing extremity was also found. This was manifested in increasing seasonal standard deviation of daily temperatures, at a rate of 11% over 55 years, and in an increase in the frequency of both 'hot' and 'cool' days. These trends are also reflected in an increase in the seasonal maximum temperatures, which is 3 times greater than the increase in minimum temperatures.