Analysis of growing degree-days as a climate impact indicator in a region with extreme annual air temperature amplitude

Abstract

We used the concept of growing degree-days (GDD) as a measure of the agricultural potential of climate on a regional scale in the southern part of the Russian Far East, the climate of which is characterized by thermal extremes. Daily maximum and minimum air temperatures were used to calculate GDD at 17 locations using threshold base air temperatures of 0, 5, 10 and 15°C, with a high-temperature threshold cut-off of 30°C. GDD increased from north to south in the study area, but the mean GDD varied considerably from one location to another. Marginal thermal conditions were observed in the north, both in the elevated areas and in the coastal regions. There was a high correlation between GDD and mean monthly temperature for the growing season from May to September (T59), such that the latter can be used as a proxy for GDD, which has implications for agricultural management. GDD and T59 had an upward trend over the 1966-2005 period for the study region as a whole. The most significant upward trend was observed for GDD0, while results for GDD15 exhibit little or no trend.