Spatial Variability And Temporal Change Character Of Soil Temperature In China

We analyzed the spatiotemporal variation of the monthly and annual temperature of 0-320 cm at differ depths,air temperature,sunshine duration and precipitation during 1965-2011.according to latitude and longitude will be divided into eight regions in China,the temporalspatial variation of 0-320 cm geothermal data were calculated by means of trend analysis and correlation analysis,and its changes in the law to make a corresponding explanation.Main conclusion is:1.During the 1965 to 2011,the monthly variation trend of 0-320 cm soil temperature in the growing season showed that the 0-320 cm soil temperature showed a significant increases.With the increase of soil depth,the soil temperature of 0-320 cm in the growing season changed gradually.0-20 cm shallow soil temperature reached the highest value in July,the maximum soil temperature of 40-160 cm in August.320 cm soil temperature is the highest in September.The results showed that the heat exchange of soil temperature at different levels had a certain lag,and with the deepening of soil depth,the soil temperature gradually decreased,and the soil heat transfer process had a certain loss.2.During the whole study period,the 0-320 cm soil temperature in the growing season showed a significant warming trend during 1965 to 2011,which was consistent with the change of air temperature.3.The variation law of the annual soil temperature of the 0-320 cm in the growing season is experienced two periods: there is no obvious change in the soil temperature of 0-320 cm during 1965 to 1987.During the 1988 to 2011,0-320 cm soil temperature showed a significant increasing,80 cm soil temperature increase rate is the highest,is 0.72 ? /10 a.the increase rate of 0-320 cm soil temperature is faster than air temperature,indicating that the response to climate change in soil temperature is more significant.4.After 1998,the air temperature increased slowly,but the inter annual variation of soil temperature continued to show a significant increase.The air temperature and soil temperature at differ depths show significant differentiation phenomenon.5.Spatially,the growth season of 0-320 cm soil temperature showed a significant increase in most areas of China during 1965 to 2011,and the high latitude areas and arid regions of the heating rate is higher than the low latitude and humid areas in China.After 1998,0-80 cm soil temperature in the southwest,northwest and Tibet Plateau showed a significant increase especially in June and August.6.During the whole study period,there is a good correlation between differ depths of soil temperature,and with the depth,the correlation between the soil temperature decreasedgradually,that heat transfer downward gradually weakened,indicating that air temperature is dominant effect on soil temperature.7.During 1998 to 2011,there was a significant positive correlation between the soil temperature and sunshine duration at differ depths of 0-40 cm in high latitude areas and arid regions,but negatively correlated with precipitation.Therefore,the change of soil temperature is not consistent with the temperature change after 1998,mainly due to the significant increase of regional sunshine duration and precipitation.Through the study,it provides a basis for the study of soil temperature at differ depths in China,and it has certain guiding significance for revealing the law of the soil temperature during the global climate change.