Abstract: In this paper, the change trend and abrupt change of shallow geotemperature in the Maqu area in upper reaches of the Yellow River in recent 40 years (1971-2010) were analyzed using the statistical methods, such as the linear trend and abrupt change analysis. The results showed that the mean monthly shallow geotemperature was significantly increased with an increase rate of 0.20-0.71 ℃·（10a）^-1, especially in soil layer of 20 cm in depth, and the increase of mean monthly shallow geotemperature at soil depth of 5 cm was the least. Shallow geotmeperature in the Maqu area increased with the increase of depth, and its anomaly was negative before 2000 but positive after 2000. The results suggested that the shallow geotemperature be the lowest in the 1970s, and its peak value occurred in the 2000s. There was an abrupt increase of summer shallow geotemperature at depths of 5, 10, 15 and 20 cm in the 1990s, and also a positive correlation between summer shallow geotemperature and summer air temperature, especially the correlation coefficient between mean summer geotemperature in soil layer of 20 cm in depth and summer air temperature was as high as 0.922. The change trends of both mean summer geotemperature in soil layer of 20 cm and air temperature were strongly consistent. There was a certain positive correlation between summer shallow geotemperature and mean winter precipitation, and the change of summer shallow geotemperature affected the winter precipitation to a certain extent.  

Key words: font-family: 宋体, mso-bidi-font-family: 宋体, mso-font-kerning: 1.0pt, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, shallow geotemperature')">mso-bidi-language: AR-SA">shallow geotemperature, font-family: 宋体, mso-bidi-font-family: 宋体, mso-font-kerning: 1.0pt, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, climate change')">mso-bidi-language: AR-SA">climate change, abrupt climate change, linear trend, Maqu, upper reaches of the Yellow River