Assessing precipitation distribution impacts on droughts on the island of Crete

摘要

Precipitation records from 56 stations on the island of Crete (Greece) revealed that areal mean annual precipitation is of a strong orographic type and its magnitude decreases in west-east direction by as much as 400mm on average. Amongst many parameters that influence precipitation, the elevation and longitude were the most important and provided the highest spatial correlation. It was found that during the year with minimum precipitation, the precipitation shortage was greater at high elevations while the precipitation excess during the year with maximum precipitation was greater in the western part of the island. The assessment of the spatial and temporal distribution of droughts was carried out with the aid of the Spatially Normalized Standardized Precipitation Index (SN-SPI) for the period 1974–2005 in order to compare drought conditions between neighbouring areas of differing precipitation heights. The analysis showed that severe droughts occurred around the year 1992–1993, with a duration of up to 3 yr. Multiple linear regression (MLR) modeling of precipitation in conjunction with cluster analysis of drought duration exhibits the linkage between precipitation, droughts and geographical factors. This connection between spatial precipitation distribution and geographical parameters provides an important clue for the respective spatial drought pattern. The above findings on the spatio-temporal drought distribution will update the current drought management plans by developing more precise drought warning systems.