Long-term changes in annual rainfall patterns in southern Israel

Within the study region in southern Israel, the annual average rainfall during the period 1961-1990 increased by up to ~ 30%, with only minor changes in the control stations representing the central and northern parts of the country. The retreat of aridity is made even more pronounced by an appreciable decrease in the coefficient of variation (CV) in nearly all of the 30 rain stations within the study region. The geographical area where maximum CV reductions were found correlates well with the area where intensive land-use variations took place with the initial operation of the National Water Carrier in 1964. A global climate change in the sea surface temperatures starting in the early 1960's may have had an effect to increase seasonal rainfall. Current research is aimed at resolving this issue.