Discussion on crop evapotranspiration and its variability regularity

The evapotranspiration in Sanhe city was calculated with Penman-Monteith formula. The relationship between precipitation and reference evapotranspiration in various hydrological years was analyzed and the items of reference evapotranspiration were compared. It was concluded that ET_(rad) of reference evapotranspiration reflects basically the dynamic regularity of reference evapotranspiration, and ET_(rad) was dominant all the year round. ET_(aero), another item of reference evapotranspiration, varied less in the whole year, in general, it was more influential to evapotranspiration in winter than in other seasons.