Response of Changes in Soil Seasonal Freeze/Thaw to Climate Change from 1950 to 2010 in China

Abstract:

Soil seasonal freeze/thaw is an important indicator of climate change and have significant influence on ground thermal and hydrological regimes, surface energy and moisture balance. In this study, we used data and information from more than 800 national meteorological stations across China to study soil seasonal frreze/thaw for the period from 1950 through 2010. Mean monthly grid air temperature data are used to investigate soil seasonal freeze/thaw state change and its response to climate change across China. The results show that mean annual air temperature(MAAT) and mean annual ground surface temperature (MAGST) are in the increasing trend by 0.029℃/year and 0.041℃/year respectively from 1967 to 2013; Declined trend of freeze day (FD) and freeze/thaw cycle (FTC) is significant, by -0.22 d/year, and -0.039 frquencies/year respectively. There is an inverse correlation between FD and MAAT and between FTC and MAAT; Mean annual area extent of soil seasonal freeze/thaw state shows a declined trend as MAAT increases. These results are important for understanding the soil freeze/thaw dynamics and effects in the ecosystem in the cold and arid regions.

Key words: climate change; freeze/thaw state; freeze day; freeze/thaw cycle;