近地层O_3和CO_2浓度变化对冬小麦影响的数值模拟:Ⅰ模型结构

NUMERICAL SIMULATION STUDY ON THE IMPACTS OF TROPSHERE O_3 AND CO_2 CONCENTRATIONS CHANGES ON WINTER WHEAT: ⅠMODEL DESCRIPTION

在试验研究的基础上,文中尝试利用数值模拟方法评估O3和CO2浓度变化对作物的影响。以农田生态系统碳氮生物化学模型(DNDC)为基础,对其中的作物子模型进行改进,加入O3对冬小麦光合作用和叶片生长影响的模拟,结合原模型中有关CO2对冬小麦光合作用影响的模拟,建立反映O3和CO2浓度变化对冬小麦生长发育和产量形成影响的作物模型。文章对DNDC模型进行了参数修正以适用于中国华北地区;文章参考前人的工作,引用了两种O3对作物光合作用影响的模拟方法进行比较,分别是O3对初始光利用率的影响和O3对叶片光合作用的直接影响;在此基础上,进一步考虑O3对冬小麦叶片生长的影响,根据试验资料,建立了O3对叶片生长影响系数。

Ozone is well documented as the air pollutant most damaging to agricultural crops and other plants. It is reported that troposphere O_3 concentration has been increased rapidly in recent 20 years. Evaluating and predicting impacts of ozone concentration changing on crops are drawing great attention in the scientific community. In China, main study method on this field is controlled experiments, for example open top chambers, but numerical simulation study about impacts of ozone on crops using crop model is rare, what’s more, the simulation study about combined impacts of ozone and carbon dioxide has not been reported. The improved agroecosystem model is presented to evaluate simultaneous impacts of troposphere O_3 and CO_2 concentration changes on crops in the paper by integrating impacts of ozone on crop growth and development algorithms with an existing agroecosystem biogeochemical model, DNDC. The main crop physiological process of crop growth (phenology, leaf area index, photosynthesis, respiration, assimilate allocation and so on) in former DNDC are kept. The algorithms about impacts of ozone on photosynthesis and winter wheat leaf are added in improved model to reveal impacts of ozone and carbon dioxide on growth development and yield formation of winter wheat coupling the simulation about impacts of carbon dioxide on photosynthesis of winter wheat which exists in former DNDC. In the paper, firstly assimilate allocation algorithms and some specie parameters (such as daily thermal time of different development stage) were modified in order that DNDC can be applied to North of China. Secondly two different kinds of impacts of ozone on crops algorithms were tried to coupling with the former model the one was impacts of ozone on light use efficiency, another was direct effects of ozone on leaves photosynthesis. The later were closer to experiment measurements through comparing results of two group simulated. At last, the method of direct impacts of ozone on leaves growth was adopted and the coefficients about impacts of ozone on leaf growth and senescence were ascertained. Effects of climate changes, increasing ozone and carbon dioxide concentration on agroecosystem are attempted to be simulated numerically in the study which is considered to be advanced and credible.