Point Measurement of Reactive Iodine Species by Resonance Fluorescence

大气层的组成对我们日常生活的许多方面都有影响，例如污染的扩散和气候。大气成分是由自然和人造化合物的排放以及转化这些化合物的化学反应决定的。这项研究奖学金的目的是发展我们对海洋地区大气中涉及碘物种的一些化学过程的理解。已知海洋生物会向大气中释放含碘化合物。在阳光的照射下，这些化合物可以分解，释放出它们所含的碘原子，然后发生化学反应，影响海洋大气：碘物质可以影响大气处理污染物排放的能力，如全球变暖气体甲烷，因为它们可以改变氧化剂物质的浓度，引发碳氢化合物的降解。最近的研究还表明，在某些条件下，气相碘物质可以在大气中凝聚形成直径为几纳米的新粒子。在爱尔兰西海岸的梅斯黑德研究站进行的测量中，发现了新粒子的爆发。这些颗粒可以增加云形成的趋势，因为它们充当水蒸气凝结的焦点。由于云层在白天将太阳辐射反射回太空，并在夜间将热量捕获在地球表面附近，海洋碘排放可能会影响我们的天气和气候。这项研究的目的是回答一个基本问题，这些过程：-什么是浓度和分布的含碘化合物在海洋大气中？这项研究将由利兹大学化学学院的William Bloss博士和Dwayne Heard教授进行，该学院将开发一种用于检测碘物质的新仪器，该仪器基于一种称为共振荧光的技术，该技术灵敏，专门检测碘原子，并且可以精确校准。该仪器将能够测量海洋大气中存在的几种碘物质，这将大大提高我们对碘化学沿着海岸线和公海作用的认识。该仪器将在利兹进行测试，并在爱尔兰的梅斯黑德研究站进行试验部署。一个特别的目标是确定碘物质是否仅限于狭窄的沿海地区，或者它们是否在开阔的海洋上以可观的水平被发现-如果是后者，那么上述过程将对大气成分产生重大影响。实地测量还将用于测试数值模型中使用的化学机制，这些模型旨在预测未来大气的组成。

The composition of our atmosphere is responsible for many aspects of our everyday life, such as the spread of pollution and our climate. Atmospheric composition is determined by emissions of natural and man-made compounds, and by chemical reactions which transform those compounds. This research fellowship aims to develop our understanding of some of the chemical processes involving iodine species which occur in the atmosphere in marine areas. Marine organisms are known to release iodine-containing compounds into the atmosphere. In the presence of sunlight, these compounds can be broken down releasing the iodine atoms they contain, which can then undergo chemical reactions which affect the marine atmosphere: Iodine species can affect the ability of the atmosphere to process pollutant emissions such as the global warming gas methane, as they can change the concentrations of the oxidant species which initiate the degradation of hydrocarbons. Recent research has also shown that under certain conditions, gas-phase iodine species can condense to form new particles in the atmosphere, a few nanometres in diameter. Bursts of new particles have been detected during measurements conducted at Mace Head Research Station on the west coast of Ireland. These particles can increase the tendency for clouds to form, as they act as focal points for water vapour to condense upon. As clouds reflect solar radiation back into space during the day, and trap heat close to the earth's surface at night, marine iodine emissions could affect both our weather and climate. This research aims to answer a fundamental question about these processes: -What are the concentrations and distribution of iodine-containing compounds in the marine atmosphere ? The research will be carried out by Dr William Bloss & Professor Dwayne Heard in the School of Chemistry in the University of Leeds, where a new instrument for the detection of iodine species will be developed, based upon a technique called resonance fluorescence, which is sensitive, specifically detects iodine atoms and can be accurately calibrated. The instrument will be able to measure several of the iodine species present in the marine atmosphere, which will greatly improve our understanding of the role of iodine chemistry along the coastline and over the open ocean. The instrument will be tested in Leeds, and during a trial deployment at Mace Head Research Station in Ireland. A particular aim will be to determine if the iodine species are restricted to a narrow coastal region, or if they are found over the open ocean at appreciable levels - if the latter, then the processes described above will have a significant impact upon atmospheric composition. The field measurements will also be used to test the chemical mechanisms used in numerical models which aim to predict the future composition of the atmosphere.