Effective temperature sums and durations of the vegetative period in Fennoscandia (1921-1950)

Abstract

Maps present the beginning, the end, the duration and the effective tem­perature sum of the vegetative period which denotes the duration of daily, mean, screen air temperatures of 5°C or more calculated from observations over period of 30 years. The maps are reduced to sea level, to rural con­ditions, to conditions without any lake effect and to conditions prevailing at sites with a low relative height. Values representative of their geographical location are calculated by making the following corrections to the values presented on the maps: the altitude correction, the lake effect correction, the urban effect correction and the relative height correction. On the basis of the data it is possible to perform general comparisons within extensive areas and detailed local comparisons within relatively small areas.