Probing the roles of reactive iodine and bromine in Arctic halogen chemistry

在这个项目中，研究小组将重新分析作为北极观测网组成部分部署的15个浮标先前收集但未经检查的反应性卤素光谱数据，以便研究溴和碘之间可能的协同作用的大小及其对北极臭氧消耗的影响。研究小组将主要关注碘化学对臭氧耗损的影响，因为最近的出版物表明，碘在北极的卤素和臭氧化学中可能比以前认为的起更关键的作用。由于本项目将使用的数据已经存在于以往的浮标光谱仪观测中，因此本工作的重点是重新分析数据，将数据与其他观测数据进行比较，并进行模拟实验，以研究北极地区潜在的碘影响大气化学。在这项拟议的工作中要检验的主要假设是，虽然活性溴在北极大部分地区仍主导着臭氧消耗化学，但与活性碘的化学协同作用可能会加速这一进程，特别是在某些地区。该项目的成功可能会对北极大气化学界、更广泛的气候研究界和公众产生强烈的积极影响。在之前NSF资助的项目中，主要关注溴化学，研究小组利用多轴微分光学吸收光谱（MAX-DOAS）从自由漂浮的浮标上观测，作为NSF北极观测网络的一部分，并确定溴是北极地区主要的消耗臭氧的反应性卤素。新的研究表明，碘的作用可能比以前认为的更为关键。现在，这些现有的测量结果将被重新分析，重点放在碘化学上，并与最近对北极地区卤素的观测结果进行比较。碘和溴量的季节性和区域分布将通过协作地面测量进行量化和验证，并将使用一维化学模型来确定碘和溴在浮标位置臭氧消耗化学中的相对作用。本项目将资助一名博士后研究员和一名本科生。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In this project the research team will reanalyze previously gathered but unexamined reactive halogen spectroscopy data from fifteen buoys deployed as a component of the Arctic Observing Network in order to study the magnitude of possible synergies between bromine and iodine and their impact on Arctic ozone depletion. The research team will focus primarily on the impact of iodine chemistry on ozone depletion as recent publications indicate that iodine may have a more critical role in halogen and ozone chemistry in the Arctic than previously assumed. As the data to be used in this project already exists from previous buoy spectrometer observations, this work focuses on reanalyzing the data, comparing the data to other observations, and conducting modeling experiments to examine the potential iodine-influenced atmospheric chemistry in the Arctic. The main hypothesis to be tested in this proposed work is that while reactive bromine still dominates ozone depletion chemistry for most of the Arctic, chemical synergies with reactive iodine may accelerate the process, particularly in some regions. Success in this project is likely to have a strong positive impact on the Arctic atmospheric chemistry community, the broader climate research community, and the public.In the previous NSF-funded project, which focused primarily on bromine chemistry, the research team utilized multiple-axis differential optical absorption spectroscopy (MAX-DOAS) observations from free-floating buoys as a part of the NSF Arctic Observing Network and determined that bromine is the dominant ozone depleting reactive halogen in the Arctic. New research indicates that iodine may have a more critical role than previously assumed. These existing measurements will now be reanalyzed with a focus on iodine chemistry and compared to recent observations of halogens within the Arctic. Seasonal and regional distributions of iodine and bromine amounts will be quantified and validated with collaborative ground-level measurements and a 1-D chemical model will be used to determine the relative role of iodine and bromine in ozone depletion chemistry at buoy locations. A postdoctoral researcher and an undergraduate student will be supported during this project.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.