An Analysis on Agricultural Temperature Indicators in Yulin and Hanzhong of Shaanxi Province from 2000 to 2020

In order to explore the change trend of temperature and its influence on crop growth in Yulin and Hanzhong areas of Shaanxi province under the background of global warming. The change trend of negative accumulated temperature, effective accumulated temperature, active accumulated temperature and accumulated days of each accumulated temperature in the two places in recent 20 years were analyzed, and the impact on crop growth was evaluated. Since 2012, all temperature elements in Yulin and Hanzhong show an increasing trend, and the fluctuation range has decreased. Since 2012, the annual maximum temperature in Yulin has been increasing at the rate of 0.44°C/year, and the annual minimum temperature has shown an obvious upward trend. The annual maximum temperature and annual minimum temperature in Hanzhong showed an increasing trend as a whole. The accumulated amount of negative accumulated temperature and the number of days of negative accumulated temperature in two places showed a downward trend. Compared with Yulin, the effective accumulated temperature, active accumulated temperature, frost-free period and growing season showed an obvious increasing trend. The highest effective accumulated temperature was 5958.8°C, the highest active accumulated temperature was 5390.8°C, and the active accumulated temperature was increasing at the rate of 20.1°C/year.