Abstract:

Accumulative temperature is an important climate resource and crop growth and development index.In this paper,using daily average temperatures of five meteorological stations in Shiyang River Basin,Gansu Province,China during 1960-2017,acumulative ≥10 ℃ temperature was determined using the sliding average method.Spatiotemporal changes in acumulative ≥10 ℃ temperature were analyzed via multiple linear regression,mean square deviation (σ),linear trend coefficient,cumulative anomaly,and signal-to-noise ratio methods.The results showed that the acumulative ≥10 ℃ temperature of Shiyang River Basin has obvious regional characteristics.In the desert area,the average and extreme values of acumulative ≥10 ℃ temperature were higher than those in the oasis plain,and the temperature in the oasis plain was higher than that in the mountainous area.The regional distribution of acumulative ≥10 ℃ temperature was closely related to the weather system,longitude,latitude,and altitude.In normal years,acumulative ≥10 ℃ temperature was the most common,the probability of which exceeded 65%,which was the ends of decline.Annual and decadal acumulative ≥10 ℃ temperatures showed a significant upward trend.The acumulative ≥10 ℃ temperature mainly occurs from May to September,with the highest peak in July.Abrupt changes in acumulative ≥10 ℃ temperature occurred in the entire basin,including Minqin and Tianzhu in 1996,and Liangzhou,Yongchang,and Gulang in 1997.When the acumulative ≥10 ℃ temperature in the Shiyang River Basin rises,the planting zones decrease and the growth period becomes shorter,which is not favorable for the high yields of cool-weather crops and while it is favorable for the warm-weather crops.This paper revealed new pattern of heat resources and its impacts on agriculture in Shiyang River Basin.This is very important for modern agricultural planning,crop variety adjustment,and agricultural quantitative evaluation.

Key words: ≥10 ℃ accumulative temperature, spatio-temporal change, multiple linear regression, Shiyang River Basin