A Numerical Simulation of the Impacts of Ozone in the Ground Layer Atmosphere on Crop Photosynthesis
近地层大气臭氧对作物光合作用影响的数值模拟研究

The increase of O 3 concentration in the ground layer has negative impacts on crop photosynthesis. The O 3 concentration above the wheat field was observed hour by hour with TE-49C ozone automonitor in Changshu, and the impact of O 3 on the wheat leaf photosynthesis was measured in the OTC-1 open top chamber simultaneously. Based on the observed parameters, a numerical model for simulating the impact of O 3 on wheat canopy photosynthesis was developed, which has higher resolution and accuracy. The results of O 3 observation showed that there are three typical patterns of O 3 diurnal variation in the Yangtze River Delta, including the unimodal curve with high concentration, multimodal curve with high concentration and smooth variation curve with low concentration. The result of numerical analysis identified that the unimodal variation with high concentration has greater impact on daily photosynthesis than the others. When the O 3 concentration and daily radiation changed synchronously, the impact of O 3 on photosynthesis becomes more intense as daily radiation increasing. The lost of the wheat photosynthesis due to O 3 in the whole growth period was integrated, and the calculated results showed that the accumulated lost of daily photosynthesis is about 9.22% in the wheat growth period under suitable moisture and fertilizer conditions.