近60年来东北地区参考作物蒸散量时空变化

Spatiotemporal variability of reference evapotranspiration over the Northeast region of China in the last 60 Years

  • 摘要: 利用东北地区106个站点1951~2007年的逐日气象资料,采用Penman-Monteith公式计算得到各站点的逐日、逐年ET0,并通过反距离插值得到逐年ET0及多年平均ET0网格数据,最后通过墨西哥帽小波变换、Mann-Kendall检验、REOF、倾向率等方法探讨了全区平均ET0及多年平均ET0的时空变化特征。研究结果表明:①全区平均ET0总体上表现较小幅度的增长趋势,其倾向率为3.89 mm/(10a),分别在1982、1953年取得最大、最小值;②在8-16年时间尺度上,全区平均ET0的周期振荡非常明显,期间经历了"少→多→少→多"4个循环交替过程,其中又以8~10年周期内的振荡最为强烈;③多年平均ET0在600~1160 mm之间,空间分异明显,其总体分布特征为:南高北低,西高东低,从东北向西南逐渐增加,等值线呈半环状;④从倾向率来看,ET0增加、减少的面积比例分别为72.61%、26.39%,其中嫩江的增加趋势最明显,倾向率为30.6 mm/(10 a),叶柏寿的下降趋势最明显,倾向率为-24.4 mm/(10 a)。

     

    Abstract: Based on the daily meteorological measurements of 106 meteorological stations in Northeast China from 1951 to 2007,the daily reference evapotran spiration (ET0) and yearly ET0 are estmiated using the Penman-Monteith equation1 Gridded annual and annual-average ET0 values for the region are produced using the inverse distance weighted interpolation method.The spatiotemporal variability of ET0 is analyzed using the methods of Mexican hat wavelet transform,Mann-Kendall test,the rotated empirical orthogonal function,and the inclination rate.The results show that:(1) a slightly increasing trend (3.89 mm/10a) is detected in the regional-average ET0 tmie series,and the regional ET0 minmium and maxmium are found in 1953 and 1982,respectively; (2) the temporal variability of regional-average ET0 has a quasi-periodicity of 8216 years experiencing four alternating stages (low-high-low-high),and in which an intensified ET0 oscillation of 8210 years is observed; (3) the annual-average ET0 ranges from 600 mm to 1.60 mm,and appears as obviously spatial difference exhibiting semiring-shaped isogramswith a gradual ET0 increment from Northeast to Southwest; and (4) the annual-average ET0 shows a increase trend over 72161% of the region doma in based on the analysis of inclination rate,while the opposite result is obtained for the rest of the region; the maxmium and minmium values of inclination rate are 3016 mm/10a at Nenjiang station and 224.4 mm/10a at Yebaishou station,respectively.

     

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