Spatial Variability of Daily Extreme Surface Air Temperatures Over Europe During 1950–2009

Abstract

The spatial variability of extreme surface air temperature has been studied across Europe over the 60-year period 1950–2009. Data of daily maximum and minimum temperature, T_max and T_min, respectively, taken from the European Climate Assessment & Dataset (ECA&D), were used to investigate their spatial variability, through parameters, DT_i = [max(T_i) − min(T_i)] and STDV(T_i), standard deviations, where i = max,min, expressing the absolute and overall spatial variability, respectively. The data are measurements from 181 stations uniformly distributed over Europe with adequate availability. Our results indicate that there is a significant spatial variability of daily T_max and T_min values over Europe. The computed values of DT_max,min range from about 17°C to 58°C, whereas those of STDV(T_max,min) range from about 3.0–11.5°C, depending on the year and season. It is found that the spatial variability of maximum temperatures over Europe has decreased from 1950 to 2009, as indicated by the computed values D(DT_max) = −0.008°C and D[STDV(T_max)] = −0.003°C. Similarly, the overall spatial variability of minimum temperatures over Europe has decreased as well, as indicated by our computed values D(DT_min) = −0.016°C and D[STDV(T_min)] = −0.006°C. The seasonal analysis, however, reveals contrasting tendencies, with decreasing D(DT_i) and D[STDV(T_i)] in winter and spring and increasing in summer.