Regional temperature and radiation indices and their adjustment to horizontal and inclined forest land
Perttu, Kurth; Morén, Ann-Sofie
Mean temperatures for the normal period (1961-90) from 513 stations in Sweden, together with their geographical positions, are used to derive temperature sums and average lengths of the growing season for different threshold values as functions of latitude and altitude. Maps are drawn showing the distribution of these temperature indices. Swedish regional average forest yield is well correlated with the temperature sums for the threshold value 5°C (Pearson correlation coefficient: 0.89). Solar radiation data for the period 1983-91 from 14 stations in Sweden are used to estimate global radiation reaching the earth's surface during clear days and during days irrespective of cloudiness. This data set is also used to derive global radiation sums expressed as functions of latitude and altitude. Corrections for an approximate adjustment of temperature indices to the soil surface level and with respect to local continentality/maritimity are proposed. The solar radiation on slopes has been calculated for various inclinations and azimuths.
Publisher: Faculty of Forestry, Swedish University of Agricultural Sciences
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