黄河上游玛曲地区浅层地温对气候变暖的响应

Response of Shallow Geotemperature to Climatic Change in the Maqu Area in Upper Reaches of the Yellow River

利用1971—2010年黄河上游玛曲地区5—10月浅层地温观测资料,采用气候倾向率等现代统计诊断方法,对玛曲地区近40 a来浅层地温的变化趋势、气候突变特征进行了分析。结果表明:黄河上游玛曲地区各月平均浅层地温以0.20～0.71℃.(10a)-1的速率上升,其中20 cm平均地温增温的趋势最显著,5 cm平均地温增幅最小,浅层地温升温的趋势随深度的增加而更为显著。在2000年之前,浅层地温以负距平变化为主,2000年之后为正距平。20世纪70年代浅层地温最低,2001—2010年达到最高。1971—2010年夏季玛曲地区5、10、15、20 cm浅层平均地温均发生了升高突变。夏季浅层平均地温与同期的平均气温呈显著的正相关,其中20 cm平均地温与同期平均气温的相关性最为显著,相关系数达到0.922,且两者在变化趋势上有着很强的一致性。夏季浅层平均地温与冬季降水量存在一定的正相关,其变化对冬季降水量产生了一定的影响。

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.