Development of a Three-Dimensional Regional and Global Model for Chemical/Dynamical Evolution of Ozone and Nitrogen Oxides in the Troposphere

到目前为止，大多数全球尺度的光化学模型都包括了详细的化学，但用一维或二维处理来表示动力学，基于涡旋扩散系数的输运。这种类型的模型根据整个纬度带上平均的氮氧化物和其他物种的浓度来计算光化学产生和损失项。它们忽略了氮氧化物浓度的地理差异，其范围超过三个数量级。这种类型的模型不能用于评估具有复杂来源-受体关系的特定地点(例如北大西洋)的物种密度。由于化学中的非线性，即使是全球平均物种浓度的计算也可能存在缺陷。污染环境或生物质燃烧地区的光化学产品和损失率与偏远的大陆或海洋地区有很大不同，而且光化学产品的损失率还取决于当地的气象条件。全球光化学生产和损失的模型必须考虑到这些差异。该项目旨在开发一个现实的化学模块，该模块虽然能够模拟与大气污染有关的复杂的氮、碳氢化合物和臭氧化学，但将在全球化学运输模型中高效运行。该化学模块将在GFGL全球化学品运输模型中进行开发和测试。成功地开发了一种化学模块，它真实地模拟了氮氧化物和臭氧的光化学产生和损失，并在全球运输模型中经济地运行，这提供了一些科学上的好处。准确的三维模型是评估全球对流层光化学演化的重要工具，其方式包括地理变化和气象事件的幕式性质。三维模型还允许将结果与观察到的物种浓度进行直接比较。

To date most models for global-scale photochemistry have included detailed chemistry but have represented dynamics with a one- or two-dimensional treatment with transport based on eddy diffusion coefficients. Models of this type calculate photochemical production and loss terms based on concentrations of nitrogen oxides and other species averaged over an entire latitude band. They omit the geographical variation in nitrogen oxides concentrations which ranges over three orders of magnitude. Models of this type cannot be used to evaluate species concentrations in specific locations (e.g. the north Atlantic) that have complex source-receptor relations. Even the calculation of global average species concentrations may be flawed due to nonlinearities in the chemistry. Photochemical production and loss rates are very different in polluted environments or in regions of biomass burning than in remote continental or marine locations, and rates also depend on local meteorology. Models for global photochemical production and loss must account for these differences. This project is designed to develop a realistic chemical module which, while capable of simulating the complex nitrogen, hydrocarbon and ozone chemistry associated with atmospheric pollution, will run efficiently and effectively in a global chemical transport model. The chemical module will be developed and tested in the GFGL global chemical transport model. Successful development of a chemical module that realistically simulates photochemical production and loss of nitrogen oxides and ozone and that economically operates in a global transport model offers a number of scientific benefits. Accurate three imensional models are an essential tool for evaluating photochemical evolution in the global troposphere in a way that includes geographical variation and the episodic nature of meteorological events. A three dimensional model also allows direct comparison of results with observed species concentrations.