Abstract:
Based on the monthly mean surface air temperature and shallow ground temperature data at the depth of 0~20 cm from 1961 to 2017 in Xinyang City, located in central North and South Transition Zone, the temporal characteristics of shallow ground temperature and its response to climate change were analyzed by using the statistical, Mann-Kendall test and power spectral analysis methods. The main conclusions were as follows:(1) During the past 57 years, the annual mean shallow ground temperature for each layer showed a significantly warming trend. (2) Significant periodicity of 2~4 a was detected in annual and seasonal mean ground temperature over the past 57 years, and the quasi-cycles were obvious especially in the autumn and winter seasons. (3) During the early 1990s, there the existed significant abrupt changes in Xinyang ground temperature of 5 cm, 10 cm and 20 cm. However, the ground temperature of 0 cm turned from cold to warm conditions during the late 1990s. (4) The shallow ground temperature was significantly correlated with the surface air temperature in Xinyang. The most sensitive layer to climate change was the surface layer.