Typology and cartography of the average climate in the northern half of France - Prospects for use in forest-environment relations

Abstract

In order to establish a relationship between the environment and the yield of forest species, this article studies and maps the variability of the medium climate in the plain areas of the northern half of France. The data used are the monthly means of temperature (64 experiment stations) and precipitation (624 experiment stations) obtained between 1951 and 1980. The sums of the temperature values registered between October and March and between April and September reflect the variability of the monthly temperature. A predictive model of the monthly temperature values is defined in relation with the altitude, the latitude and the longitude. The annual precipitations and the type of pluviometric distribution synthesize well the twelve monthly precipitations. The modelization of the water balance using the Thornthwaite method allows one to build an index : the relative water deficit is mainly related to the height of precipitations for the April - September period. This index should be connected with the yield of forest species.