Temporal And Spatial Variations Of 5 Cm Ground Temperature And Its Response To Climate Change In Henan Province During 1961—2020

Since the Industrial Revolution,the global climate is undergoing a remarkable change characterized by warming.Ground temperature is an important index to evaluate climate change,which has an important impact on soil composition,structure,formation and evolution.It is of great significance for deeply understanding the interaction mechanism between earth and atmosphere and predicting the development trend of soil temperature on analyzing the temporal and spatial variations law of soil temperature and its relationship with climate change in the future.Henan Province,located in the middle of China,is a transitional zone between east and west and north and south,which plays a role in connecting east with west and connecting north and south.As a major agricultural province and an important grain production base in China,the study on the temporal and spatial variations of ground temperature in Henan Province can provide reference for rational utilization of climate resources and adjustment of crop planting structure.Based on the monthly data of 5 cm average ground temperature,air temperature,precipitation and sunshine hours at 121 meteorological stations in Henan Province from1961 to 2020,the temporal and spatial variations characteristics of 5cm ground temperature and its response to climate change in recent 60 years were analyzed by mathematical statistical methods such as trend analysis,correlation analysis,partial correlation analysis,sensitivity and relative contribution rate calculation,supplemented by GIS spatial analysis technology.The relative contribution rate of different meteorological elements to 5 cm ground temperature change was quantitatively estimated,and the robustness of ground temperature response to different climate elements was discussed.The main conclusions are as follows:(1)From 1961 to 2020,the annual average temperature in Henan Province showed a significant warming trend,with obvious oscillation periods of 30 years and 15 years;The annual precipitation had a trend of no significant decrease,showing significant periodic signals of 8,10,17 and 31 years;The annual sunshine hours in Henan showed a significant decreasing trend,with 36 year,19 year and 9 year periods detected,and abrupt changes occurred in 1987,but no significant abrupt changes were detected in the annual average temperature and annual precipitation.Spatially,the average annual temperature and annual precipitation were high in the southeast and low in the northwest,while the annual sunshine hours were less in the south and more in the north.The change rate of annual temperature was directly proportional to latitude and altitude.The annual precipitation increases most obviously in eastern Henan,while the change rate of annual sunshine hours was slow in the east and fast in the west.There were significant seasonal differences in temperature,precipitation and sunshine hours changes in Henan Province.(2)From 1961 to 2020,the annual average ground temperature in Henan Province showed a significant increasing trend,with periodic oscillations of 13～16 years and 28～32years,but no obvious abrupt change of climate was detected.There were significant seasonal and regional differences in ground temperature change,and the trend of ground temperature change is increasing in other seasons except summer.Spatially,the annual and four seasons average temperature changes showed a spatial pattern of high in the south and low in the north.(3)The annual average ground temperature of 5 cm in Henan Province was positively correlated with the annual average air temperature,negatively correlated with precipitation,and not significantly correlated with sunshine.The contribution rate of annual average temperature to annual average ground temperature was the largest,which was 82.8%,followed by precipitation,which was 14.1%,and the contribution rate of annual sunshine hours to annual average ground temperature is the smallest,which was only 3.1%.Soil temperature of 5 cm depth has strong robustness to air temperature and precipitation,but relatively weak robustness to sunshine hours.