Simulation and analysis of cucumber canopy temperature in greenhouse in Yangtze River delta during summer

A greenhouse vegetation canopy temperature simulation model was developed based on vegetation canopy energy balance. Experiment was carried out in a Dutch Venlo-type greenhouse in Shanghai during summer to collect microclimate and vegetation data to validate the model, and the sensitivity of the canopy temperature to interior air temperature, net radiation and transpiration rate was analyzed. The simulated canopy temperature agreed well with the measured data. The correlation determination coefficient (R²) and standard error(SE) between the simulated and measured canopy temperature were 0.8321 and 0.0037℃(June 24 to July 12, 2002), respectively. The multiple regression model between canopy temperature and interior air temperature, interior air humidity, net radiation and transpiration rate was developed and validated during experimental period with R² and SE being 0.9996 and 0.8829℃, respectively. The sensitivity study of the canopy temperature shows that the interior air temperature is the most influential factor,and it can be regarded as main factor to predict canopy temperature.