DOAS (Differential Optical Absorption Spectroscopy) Measurements during CONTRAST (CONvective Transport of Active Species in the Tropics)

科罗拉多大学博尔德分校的研究人员试图测量一些微量卤素化合物的柱丰度，如氧化溴（BrO）、氧化碘（IO）、氧化碘（IO）、氧化溴（BrO）、氧化碘（IO）、氧化溴（BrO）等。二氧化氯（OClO）和其他微量气体。在北方冬季，含有这些反应性气体的对流层表面气团可能优先被强烈的热带对流输送到太平洋暖池区域上方的TTL平流层低层。在这里，它们可能会影响平流层下层的化学成分，包括臭氧的化学成分。对流层上层独特的低臭氧环境预计会导致OH自由基水平非常低，这可能会增加主要通过羟基（OH）自由基氧化损失的活性气体的寿命。深层对流的同时发生和TTL中有机化合物寿命的延长对平流层卤素收支有显著影响。CONTRAST实验的时间被设计为利用计划在同一时间和地理位置进行的两个国际机载研究的合作。它们是NASA EV1项目ATTREX（机载热带对流层顶实验）和欧洲CAST（热带协调机载研究）。通过互补的仪器有效载荷，NSF GV、NASA“全球鹰”和英国BAE146的协同飞行，将对热带西太平洋从地表到19公里的整个大气柱进行前所未有的检查。

As part of the larger CONTRAST (Convective Transport of Active Species in the Tropics) measurement campaign, which has the main objective of measuring the transport of reactive chemical species into the topical Tropopause Transition Layer (TTL) over the western Pacific warm pool, University of Colorado-Boulder researchers seek to measure the column abundances of a number of trace halogen compounds e.g., bromine oxide (BrO), iodine oxide (IO), chlorine dioxide (OClO) along with other trace gas species.During northern winter, surface tropospheric air masses containing these reactive gases may be preferentially transported by intense tropical convection high into the TTL lower stratosphere over the region of the Pacific warm pool. Here they may impact the chemistry of the lower stratosphere, including its ozone chemistry. The unique low-ozone environments in the upper troposphere are expected to result in very small levels of OH radicals, which can be expected to increase the lifetime of reactive gases whose main loss is through hydroxyl (OH) radical oxidation. The simultaneous occurrence of deep convection and prolonged lifetime of organic compounds in the TTL can have significant impact on the stratospheric halogen budget.The timing of the CONTRAST experiment has been designed to take advantage of collaborations with two international airborne studies planned for the same time and geographic location. These are the NASA EV1 project ATTREX (Airborne Tropical Tropopause Experiment) and the European CAST (Coordinated Airborne Studies in the Tropics). With complementary instrument payloads, coordinated flights of the NSF GV, the NASA Global Hawk and the UK BAE146 will provide an unprecedented examination of the full atmospheric column, from surface to 19 km, in the Tropical Western Pacific.