Estimating grapevine transpiration in greenhouse with three different methods in a Penman–Monteith model in Northeast China

urate estimate of transpiration is fundamental to develop water-saving management practices and optimize irrigation management. Penman–Monteith (P–M) model based on aerodynamic resistance ( r a ) estimated from heat transfer coefficient method and Perrier logarithm method were used to calculate the hourly and daily grapevine transpiration in solar greenhouse. The results show that the daytime canopy resistance ( r c ) of grapevines was basically maintained between 200 and 250 s m −1 during the two growing seasons. The main convection type in the greenhouse was free convection (68.8–87.5