我国东西部地区地气温差的年代际变化特征

Characteristics of Interdecadal Variability in the Difference Between Surface Temperature and Surface Air Temperature in Southeast and Northwest China

利用1960～2006年我国地温、气温逐日4个时次[02：00（北京时间，下同）、08：00、14：00和20：00]的台站观测资料，计算并分析了我国东南、西北地区各季地气温差的年代际变化特征。分析结果表明：我国东南部地区各季地气温差在20世纪70年代末以前，大部分年份偏高，高于平均值，而在20世纪70年代末以后，我国东南部地区各季地气温差偏低，在夏季和冬季表现尤为明显。我国西北地区春季和夏季地气温差在20世纪70年代末以前大部分年份偏低，低于平均值；而在20世纪70年代末以后，地气温差则大部分年份明显偏高。我国西北地区秋季地气温差的年代际变化特征不明显，而冬季地气温差的年代际变化趋势与春夏季相反，在20世纪70年代末以前大部分年份偏高，高于平均值，而在20世纪70年代末以后偏低。另外，发现地温和气温对我国东南、西北地区各季地气温差的年代际变化在各季所起的贡献作用不同。

The characteristics of the interdecadal variability in the differences between surface temperature （Ts） and surface air temperature （Ta） are analyzed, using daily-observed surface temperature and surface air temperature data from 1960 to 2006. Analysis results show that there is a clear interdecadal variability in Ts-Ta in Southeast and Northwest China. Before the late 1970s, the Ts-Ta anomalies were mostly positive in Southeast China, but they mostly became negative after this period. In contrast, in Northwest China, the Ts-Ta anomalies were mostly negative in spring and summer before the late 1970s, but became largely positive after this time. The opposite trend can be seen in the variability of Ts-Ta in Northwest China in the winter. However, in the autumn in Northwest China, the interdecadal variability of Ts-Ta was not as clear as during the other seasons. The analyzed results of Ts and Ta over the study period show that their contributions to interdecadal variability of in Ts-Ta differed between different seasons.