Quantifying the impact of biomass burning and stratosphere-troposphere exchange on tropospheric ozone using Aura data and 3-D modelling

平流层中的臭氧保护地球上的生命免受有害的紫外线辐射。然而，在对流层中，它是一种有害的污染物，会增加肺病的发病率，降低作物的产量。人类活动并不直接排放臭氧。然而，它们确实会释放出许多分子，这些分子参与形成臭氧的化学反应。因此，在我们控制臭氧水平之前，我们需要了解这些其他分子来自哪里以及它们如何导致臭氧形成。臭氧前体分子的一个主要来源是生物质的燃烧：这也以其他方式造成空气质量差。生物质燃烧产生的污染扩散到地球仪各地，影响到距离污染源很远的地区。对流层的化学成分很复杂，需要详细的计算机模型来模拟其行为。由于对流层中的一些臭氧来自平流层，因此使用一个模拟两个区域及其之间空气输送的单一模型是有利的。TOMCAT/SLIMCAT三维模型是这种类型的最先进的模型。几十年来，卫星对平流层中的痕量化学物质进行了全球测量。对对流层做同样的事情要困难得多。Aura是2004年7月发射的一颗卫星，执行这一使命。四个仪器在Aura上飞行，其中三个用于测量对流层化学。这三个工具以不同的方式运作，具有非常不同的优缺点。本提案的目的是增进对产生对流层臭氧的过程的了解。为了实现这一点，我们将联合收割机的数据从Aura与TOMCAT/SLIMCAT模型。首先有必要评估模型与测量值的一致程度。为了进行这种比较，有必要在进行测量的相同时间和地点以相同的方式从模型中提取数据。在完成这项评估后，我们打算从测量结果向后推算，以估计有多少各种污染物分子被排放，从而估计有多少生物质被燃烧。我们还将估计对流层中有多少臭氧来自平流层。

Ozone in the stratosphere protects life on Earth from harmful ultraviolet radiation. In the troposphere, however, it is a harmful pollutant, increasing the incidence of lung disease and decreasing the productivity of crops. Human activities do not emit much ozone directly. However, they do emit many molecules which participate in chemical reactions which form ozone. So, before we can control the levels of ozone, we need to understand where these other molecules come from and how they cause ozone to form. A major source of ozone precursor molecules is the burning of biomass: this also contributes to poor air quality in other ways. Pollution from biomass burning spreads around the globe, affecting areas at great distances from its sources. The chemistry of the troposphere is complex, requiring detailed computer models in order to simulate its behaviour. Because some of the ozone in the troposphere comes from the stratosphere, it is advantageous to use a single model that simulates both regions and the transport of air between them. The TOMCAT/SLIMCAT three-diemnsional model is a state-of-the-art model of this type. Satellites have made global measurements of trace chemicals in the stratosphere for several decades. To do the same for the troposphere is much more difficult. Aura is a satellite, launched in July 2004, which carries out this mission. Four instruments fly on Aura of which three make measurements of tropospheric chemistry. These three instruments operate in different ways and have very different strengths and weaknesses. The purpose of this proposal is to gain an improved understanding of the processes that produce tropospheric ozone. To achieve this, we will combine data from Aura with the TOMCAT/SLIMCAT model. It will first be necessary to assess the degree to which the model agrees with the measurements. In order for this comparison to be made, it is necessary to extract data from the model at the same times and places and in the same manner as the measurements are made. With this assessment done, we then intend to work backwards from the measurements, in order to estimate how much of various pollutant molecules are being emitted and hence how much biomass is being burned. We will also estimate how much of the ozone in the troposphere comes from the stratosphere.