Experimental and Theoretical Studies of Potential New Atmospheric Sources and Sinks of Nitrous Oxide

9526510葡萄酒这个项目涉及大气一氧化二氮源和汇的问题。该物种是平流层中破坏臭氧的一氧化氮自由基的主要来源。此外，它是一种温室气体，其浓度一直在增加。目前人们认为，一氧化二氮除了在地面和海洋中的微生物活动外，没有其他自然来源，其破坏完全是通过光解和与高层大气中激发的原子氧反应来实现的。然而，目前对源和汇的估计表明，存在一个目前未被识别的源。此外，最近对大气一氧化二氮同位素组成的测量不能用可接受的来源来解释。本项目将进行实验室实验，以研究在氧气存在的情况下，电子激发的二氧化氮和羟基自由基与分子氮反应生成一氧化二氮的可能性。化学动力学模拟研究将调查为什么在没有添加臭氧的氮气/氧气混合物的紫外线照射下有效地生成一氧化二氮，而不是在所有三者的混合物中生成一氧化二氮。这些计算将为今后一氧化二氮产生和销毁问题的实验研究提供指导。***

9526510 Wine This project addresses the subject of sources and sinks of atmospheric nitrous oxide. This species is the dominant source of ozone-destroying nitric oxide radicals in the stratosphere. Furthermore, it is a greenhouse gas, and its concentration has been increasing. The current belief is that nitrous oxide has no natural sources other than microbiological activity in the ground and oceans, and its destruction is solely by photodissociation and reaction with excited atomic oxygen in the upper atmosphere. However, current estimates of sources and sinks suggest the existence of a currently unrecognized source. Furthermore, recent measurements of the isotopic composition of atmospheric nitrous oxide cannot be explained by accepted sources. Laboratory experiments will be performed in this project to investigate the potential formation of nitrous oxide from the reactions of electronically excited nitrogen dioxide and hydroxyl radicals with molecular nitrogen in the presence of oxygen. Chemical kinetics modeling studies will investigate why nitrous oxide is efficiently formed upon UV illumination of a nitrogen/oxygen mixture without ozone added, but not in a mixture of all three. These calculations will provide guidance for future experimental investigation of the issue of nitrous oxide production and destruction. ***