基于植被分区的秦岭年降水分区验证及其年际变化

The validation of precipitation zones in Qinling Mountains by vegetation classification and its inter-decadal change

通过旋转经验正交分解方法对秦岭年降水量进行分区,比较秦岭降水量客观分区与植被南北分界线的一致性,运用滑动t检验、累积距平和小波方法分析了各分区的气候变化特征。主要结论为:秦岭区域可以按年降水量分为4个区域,其中秦岭中段南北分区与植被分区界线相近,走向相同;秦岭各分区多年降水量一致表现为减少趋势,近57年来,各区大约减少了一成左右的降水量;秦岭区域年降水量在近57年里发生了多次转折,最明显的转折期发生在20世纪80年代,2001年前后秦岭区域降水出现了波动增加的趋势,但增加的趋势强度还比较弱,难以达到20世纪80年代的丰水顶峰时期;秦岭各分区最显著震荡周期2~4年。建议在开展气候区划和气候变化研究时,应该考虑年降水量分区与植被自然分区的一致性。

The coherence between the objective precipitations regional differentiation and the boundary of vegetation classification from south to north in the Qinling Mountains was compared based on REOF(Rotated Empirical Orthogonal Function)analysis,and areas with similar precipitation change in the time evolution were classified as one zone.The precipitation change feature is analyzed by using the moving t test,cumulative anomaly and wavelet method.The main conclusions can be drawn as follows:the Qinling Mountains area was divided into four zones,the boundary between middle sections on the north and south sides had similar locations and directions with the boundary of vegetation classification in the same area;precipitation in all the zones showed a decreasing trend and the reduction amount was about-10%in the last 57 years;there were several fluctuations of precipitation in the study period,and the peak amount was observed in the 1980 s.An ascending trend appeared after 2001,but it was too weak to reach the peak point in the 1980 s;the strongest period in the four zones was 2-4 a.At last,it is suggested that the coherence between the division zone of annual precipitation and natural vegetation should be involved in the study of climate classifications and climate change.