Bromide in Snow in the Sea Ice Zone

极地纬度的一系列化学和微物理途径，包括春季（对流层）臭氧耗损、汞的氧化途径以及导致云量和随之而来的地表能量收支变化的云凝结核（CCN）的产生，都被认为依赖于海冰中形成的卤素气体的排放。气候变暖导致海冰范围减少的前景，导致这些不完全已知的地表-大气反馈和相互作用的改变，需要在实验室研究和实地活动中确认机理细节。其中一个机制问题是，富溴（BrO和Br）的雪是如何通过海冰的过程迁移或形成的，然后再以气溶胶的形式被强风动员到大气中。一旦升到高空，它可能与臭氧和其他大气物质发生反应。达特茅斯学院的研究人员将从海冰表面、自由吹起的雪和罗斯海伯德角的海冰核中收集雪。随后将使用一系列光谱、微分析和微观结构方法来确定海冰中溴的分布梯度，以阐明海冰如何首先形成，然后将溴释放到极地大气边界层中。

A range of chemical and microphysical pathways in polar latitudes, including spring time (tropospheric) ozone depletion, oxidative pathways for mercury, and cloud condensation nuclei (CCN) production leading to changes in the cloud cover and attendant surface energy budgets, have been invoked as being dependent upon the emission of halogen gases formed in sea-ice. The prospects for climate warming induced reductions in sea ice extent causing alteration of these incompletely known surface-atmospheric feedbacks and interactions requires confirmation of mechanistic details in both laboratory studies and field campaigns. One such mechanistic question is how bromine (BrO and Br) enriched snow migrates or is formed through processes in sea-ice, prior to its subsequent mobilization as an aerosol fraction into the atmosphere by strong winds. Once aloft, it may react with ozone and other atmospheric species. Dartmouth researchers will collect snow from the surface of sea ice, from freely blowing snow and in sea-ice cores from Cape Byrd, Ross Sea. A range of spectroscopic, microanalytic and and microstructural approaches will be subsequently used to determine the Br distribution gradients through sea-ice, in order to shed light on how sea-ice first forms and then releases bromine species into the polar atmospheric boundary layer.