Temperature Change Characteristics in Gansu Province of China

Abstract

The applicability of reanalysis data has been widely addressed in climate and hydrology studies over the past two decades. In this study, we analyzed spatiotemporal variations in ERA-Interim temperature data from four climate zones within Gansu Province from 1979 to 2017 by using linear regression model and Mann-Kendall mutation test. Results showed that: (1) The highest temperature was found in the subtropical monsoon climate zone, and the lowest in the plateau mountain climate zone. Temperatures in high-elevation regions were lower than those in low-elevation regions; (2) The annual mean temperature increased across Gansu Province from 1979 to 2017. The lowest warming rates of annual mean, annual maximum, and annual minimum temperatures were found in the subtropical monsoon climate zone, and these were 0.334, 0.300, and 0.336 °C/10a, respectively. The highest warming rates of annual mean and annual minimum temperature were found in the temperate monsoon climate zone, and these were 0.420 and 0.464 °C/10a, respectively. The highest warming rate of annual maximum temperature was found in the temperate continental climate zone (0.471 °C/10a); (3) The Mann-Kendall analysis showed that the mutation times of annual mean temperature of the subtropical monsoon, temperate monsoon, and temperate continental climate zones in Gansu Province were all in 1997. The mutation times of annual maximum temperature were found in the subtropical monsoon climate zone (1997) and temperate monsoon climate zone (1997). The mutation times of annual minimum temperature were found in the temperate continental climate zone (1997) and plateau mountain climate zone (1994). ERA-Interim reanalysis data are reliable for capturing mutation time of temperature, especially in the high-elevation areas with rare meteorological station. This study can provide a reference when analyzing climate change at different climatic zones using reanalysis data.