[Objective]The study aimed to analyze the changing characteristics of evaporation in Cangzhou City in recent 40 years. [Method] Based the observation data of evaporation measured by small evaporation pans( with the caliber of 20 cm) from weather stations of Cangzhou during 1971-2010,the monthly,seasonal,annual and decadal variation of evaporation were analyzed using conventional assessment methods. [Result] During 1971-2010,monthly average evaporation in Cangzhou fluctuated within a year,and the maximum value appeared in June,while the minimum value appeared in January. Within a year,average evaporation was the highest in summer,and its variation was the greatest; it was the lowest and varied most slightly in winter. During 1971- 2010,evaporation in winter showed an increasing trend,while evaporation showed a decreasing trend in spring and autumn,and there was no obvious change in evaporation in summer. Annual average evaporation in Cangzhou showed a decreasing trend from 1971 to 2010,and the highest evaporation reached 2 273. 3 mm,appearing in 1972. The lowest evaporation was only 1 681. 4 mm,appearing in 1990,and the difference between them reached 591. 9 mm. Average evaporation in each decade showed a decrease trend,and the maximum value appeared in the 1980s( 1 958. 6 mm),while the minimum value appeared in the first ten years of the 21stcentury( 1 880.9 mm). [Conclusion]The research could provide theoretical references for studies on climate change in Cangzhou in future.
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