欧亚大陆干旱半干旱区感热通量的时空变化特征

利用1958—2002年ERA-40再分析感热通量资料进行EOF分析,结果显示,无论春季还是夏季,欧亚大陆干旱半干旱区感热通量都有3个主模态。第1模态都表示空间分布的一致性,20世纪70年代中后期开始,欧亚大陆干旱半干旱区春季感热通量明显增强,而夏季却明显减弱。第2、3模态表示了空间分布的不一致性,且存在年际、年代际变化特征。小波分析结果表明,欧亚大陆春、夏季感热通量存在明显的年际、年代际变化特征,且年代际变化信号强于年际变化信号。

Characteristics of Temporal and Spatial Variations of Sensible Heat Flux in the Arid and Semi-arid Region of Eurasia

Based on the ERA-40 reanalysis data of sensible heat flux during 1958—2002,the characteristics of temporal and spatial variations of summer and spring sensible heat flux in Eurasia（including Middle Asia,Mongolia and Northwest China） are analyzed by use of EOF and Morlet wavelets analysis methods.The results show that there are three principal spatial patterns of sensible heat flux in the arid and semi-arid region of Eurasia in spring or summer.The first pattern shows the space consistency of sensible heat flux in the region of Eurasia,inwhich the sensible heat flux obviously increases in spring,but markedly decreases in summer from the middle and late of 1970s.The second and third patterns show spatial heterogeneity of sensible heat flux in the region of Eurasia with interannual and interdecadal variabilities.Besides,the Morlet wavelets results show that the sensible heat flux are dominated by interannual and interdecadal variabilities in spring and summer,and the signal of interdecadal variability is more significant than that of interannual variability.