Influence Of Smog Optical Effect On Plant Photosynthesis And Vegetation Productivity Estimation

With the continuous acceleration of the industrialization process,frequent haze weather has led to an increase in aerosol particles in the air.Aerosols can change the composition of the radiation spectrum that reaches the ground,that is,the light quality.Light is an important factor affecting photosynthesis.It is essential to study how changes in light quality affect the photosynthetic characteristics of plants.At present,there are few studies on changes in light quality and how light quality affects photosynthesis.In this paper,we use FvCB photosynthesis model and Li-6800 photosynthesis instrument to obtain a large amount of measured data of sweetgum leaves,the purpose is to simulate the light quality,that is,the ratio of red and blue light changes on plant photosynthetic characteristics and physiological and biochemical characteristics,and establish a statistical model to quantify this effect.Then,the influence of the light quality factor is added to the estimation model of the total land primary productivity GPP,and finally the estimation accuracy of the model is improved.We Provides new methods and ideas for the improvement and development of the model.The specific results are as follows:(1)Aerosols affect the ratio of red light to blue light in solar radiation.Under the condition of aerosol,the ratio of red light to blue light is higher than that without aerosol.This shows that aerosols cause an increase in the proportion of red light in solar radiation.(2)The simulation results under different light quality conditions based on the FvCB model show that when the ratio of red to blue light is 7: 3,the light response curve and the carbon dioxide response curve have good fitting results.At 7: 3,the net photosynthetic rate(A)and stomatal conductance(gs)were significantly higher than other measured ratios.And the electron transfer rate(J)is also the largest in proportion.By analyzing the light intensity parameters under different light quality conditions,the apparent quantum efficiency(AQY)and dark respiration rate(Rd)are also the largest at a red-to-blue ratio of 7: 3.(3)Quantifying the effect of light quality on photosynthesis by constructing statistical models.First of all,the ratio of red and blue light is 7: 3 as the basis of light quality standardization,and the result is a statistical model of light quality ratio and photosynthetic effective radiation.The model explains the relationship between light quality changes,light intensity and photosynthetic rate.(4)The influence of the quantified light quality on photosynthesis is added to the GPP estimation model,which improves the simulation accuracy of the light energy utilization model.Taking the GPP estimation of the Beijing Da xing site from April to October of 2006-2009 as an example,the simulation accuracy of the VPM-EF model and the MOD algorithm after adding light quality has been improved by 14.97% and 10.37%,respectively.