Multi-factor analysis of DTR variability over Israel in the sea/desert border

The contributions of twelve independent factors/variables to the magnitude of the local diurnal temperature range (DTR) in Israel were examined, and five to seven were found to contribute significantly. Israel was chosen due to its complex terrain with several climatic zones and proximity to the Mediterranean Sea. The seven sites for this study represent different terrains, from mountainous with a Mediterranean climate to desert. Each site had 6 years of data available. Stepwise analysis was performed in order to determine the contribution of each factor/variable at each site. The linear correlations between the DTR and each factor were calculated. These were carried out at each site for the whole year and for each season, separately. Relative humidity was found to have the largest DTR contribution at all sites, for 3 seasons, except summer at shoreline sites and in Jerusalem. The daily cloud cover and the wind speed had small contributions in most sites. The magnitude of the DTR was found to vary largely with location and to be considerably smaller in the seashore sites than those inland.