Spatial distribution and temporal variation of reference evapotranspiration during 1961–2006 in the Yellow River Basin, China
2011
Yang, Zhifeng | Liu, Qiang | Cui, Baoshan
To explore the spatial and temporal variations of the reference evapotranspiration (ETᵣₑf) is helpful to understand the response of hydrological processes to climate changes. In this study, ETᵣₑf was calculated by the Penman-Monteith method (P-M method) using air temperature, wind speed, relative humidity and sunshine hours at 89 meteorological stations during 1961–2006 in the Yellow River Basin (YRB), China. The spatial distribution and temporal variations of ETᵣₑf were explored by means of the kriging method, the Mann-Kendall (M-K) method and the linear regression model, and the causes for the variations discussed. The contribution of main meteorological variables to the variations of ETᵣₑf was explored. From the results we found that: (1) the spatial distributions of ETᵣₑf display seasonal variation, with similar spatial patterns in spring, summer and autumn; (2) temporal trends for ETᵣₑf showed large variation in the upper, middle and lower regions of the basin, most of the significant trends (P = 0.05) were detected in the middle and lower regions, and, in particular, the upward and downward trends were mainly detected in the middle region and lower region of the basin, respectively; and (3) sensitivity analysis identified the most sensitive variable for ETᵣₑf as relative humidity, followed by air temperature, sunshine hours and wind speed at the basin scale.
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