Temperature fluctuations in the mediterranean area during the last 120 years

Abstract Based upon sea‐surface temperature (SST) data, recently corrected for bucket‐intake observational change, the SST fluctuations since 1873 in the Mediterranean are studied and compared with air temperature (AT) fluctuations at some land stations of this area and for the Northern Hemisphere (ATNH). Instead of the actual temperature, we used the frequency difference (per cent) of the number of the warm minus cold months, ( f w — f c ) annually and seasonally, smoothed using 10‐year moving averages. This frequency difference was found to be a linear function of the actual temperature. For the whole Mediterranean, the trend of the SST is simple enough, with a minimum in about 1910 and a double maximum in about 1940 and 1965. A secondary minimum follows in 1975–1980, very strong in the eastern Mediterranean, with a rise after that to the present. This trend when compared with ATNH presents some differences: in the ATNH a minimum appears earlier, in 1890, but this is shown only slightly in the Mediterranean SST. The second SST maximum, in 1965, is not shown in ATNH, and the general rise of recent years starts in the ATNH about 10 years earlier. When considering the AT of the Mediterranean stations, it can be seen that the rise, after the minimum of 1910, stops 15 years earlier than the SST and ATNH. Then, an anomalous and slow decrease follows until about 1975–1980, followed by a rise to the present, which is delayed in the eastern Mediterranean.