LONG-TERM INCREASES IN WESTERN MEDITERRANEAN SALINITIES AND TEMPERATURES - ANTHROPOGENIC AND CLIMATIC SOURCES

The deep water of the western Mediterranean Sea is known to have becom e warmer and saltier since about the 1950s. The causes of these change s have, however, not yet been sactisfactorily determined. Previous stu dies speculated on decreasing precipitation, greenhouse warming and/or anthropogenic reduction of the freshwater flux into the eastern Medit erranean. Here we report on results from a new oceanographic database of the western Mediterranean Sea together with determinations of longt erm changes of the fresh water budget. We analyzed temperature and sal inity data of the past 40 years to detect deviations from the longterm average. Certain areas and depth ranges are showing increases in temp erature or salinity some of which have been found earlier and some whi ch are new. From the regional and vertical distribution we conclude th at the observed increases of temperature and:salinity in the western M editerranean Sea are caused both by changes in atmospheric conditions as described by the NAO-index and by the regulation of Spanish rivers.