Spatial and temporal characteristics of actual evapotranspiration over Haihe River basin in China

• Spatial and temporal characteristics of actualevapotranspiration over the Haihe River basin in Chinaduring 1960–2002 are estimated using the complementaryrelationship and the Thornthwaite water balance (WB)approaches. Firstly, the long-term water balance equation isused to validate and select the most suitable long-termaverage annual actual evapotranspiration equations for ninesubbasins. Then, the most suitable method, the Pike equation,is used to calibrate parameters of the complementaryrelationship models and the WB model at each station. Theresults show that the advection aridity (AA) model moreclosely estimates actual evapotranspiration than does theGranger and Gray (GG) model especially considering theannual and summer evapotranspiration when compared withtheWBmodel estimates. The results from theAA model andthe WB model are then used to analyze spatial and temporalchanging characteristics of the actual evapotranspirationover the basin. The analysis shows that the annual actualevapotranspirations during 1960–2002 exhibit similardecreasing trends in most parts of the Haihe River basin forthe AA and WB models. Decreasing trends in annual precipitationand potential evapotranspiration, which directlyaffect water supply and the energy available for actualevapotranspiration respectively, jointly lead to the decreasein actual evapotranspiration in the basin. A weakening of thewater cycle seems to have appeared, and as a consequence,the water supply capacity has been on the decrease, aggravatingwater shortage and restricting sustainable social andeconomic development in the region.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences (hsv//eng)

Nyckelord

Haihe River basin

Complementary relationship

Actual evapotranspiration

Trend

China

Thornthwaite water balance model

Complementary relationship; Thornthwaite water balance model; Actual evapotranspiration; Trend; Haihe River basin; China

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