Spatial and seasonal patterns of precipitation in Greece: the terrain segmentation approach

The aim of the study is to investigate the spatial and seasonal variation of precipitation in Greece using multi-temporal data analysis techniques. Mean monthly precipitation grids of 1 km² resolution of the period 1950-2000 were used in the analysis. Cross correlation quantified spatio-temporal patterns which are summarized as follows a) the absolute correlations of precipitation versus elevation and longitude are minimized during the winter period, b) the latitude dependency of precipitation presents a seasonal shift where winter precipitation tends to be higher in northern Greece, while summer precipitation tends to be higher in southern Greece. Principal components analysis indicated that the first two components account for the 92.8% of variance in the spatio-temporal variability of precipitation in Greece. Cluster analysis segmented the terrain to 27 regions with distinct seasonal variability of precipitation. The majority of irrigated agricultural land (plains of Macedonia, Thessaly and Thrace) belong to clusters which present the lowest values of annual precipitation (<600 mm year^-1). The derivation of precipitation signatures for each region of Greece using the proposed terrain segmentation approach can support environmental decision and agricultural planning at a regional (country) scale in relation to water resources management.