Physics and Chemistry of Frost-Flowers and Their Resultant Sea -Salt Aerosol

极地地区是环境因素对全球气候影响的有力指标，南极臭氧洞、南极半岛大幅升温和北极海冰损失都表明了这一点。冰芯记录也为过去的气候变化提供了强有力的记录，如果它们能被准确地解释的话。传统上，人们一直认为，冰芯中海盐浓度越高，海冰越少，风越强，海盐是由风对开阔海水的作用产生的。然而，现在人们认为，极地地区的海盐气溶胶主要是由浮冰内的海冰表面产生的，包括霜花，而不是来自开阔的水域。由于冰芯在冻结过程中的分馏，气溶胶在冰芯中引起明显的负非海盐硫酸盐。这意味着，现实与传统观点截然相反：冰芯中海盐的增加与更多的海冰有关，而冰芯中更多的新结冰区域与微风有关。这种通过霜花产生的海盐气溶胶的海冰来源可以解释冰期海盐到冰芯的通量比暖期更大这一观察结果。霜花也几乎肯定要对春季地表臭氧的损失负责，因为霜花或其气溶胶会产生活性溴气体。如果我们要充分解释过去和未来的极地环境变化，我们对这些复杂过程的理解是至关重要的。我们还必须将它们参数化，以便我们能够模拟变化，但目前还没有完整的参数化霜花的形成或它们以气溶胶的形式扩散到大气中。在这里，我们将测量霜花生长的物理和化学以及它们的气溶胶在实验室中的扩散，并对所涉及的过程进行参数化。

Polar regions are strong indicators of the impact of environmental factors upon global climate, as indicated by the Antarctic ozone hole, by large temperature increases on the Antarctic Peninsula, and by Arctic sea ice loss. Ice core records also contribute a powerful record of past climate changes provided they can be interpreted accurately. Traditionally, it has been assumed that greater sea salt concentrations in ice cores showed less sea ice and stronger winds, with sea salt being generated by the action of wind on open ocean water. However, it is now believed that sea salt aerosol in polar regions is generated mostly from the sea ice surface within the ice pack, including from frost flowers, rather than from open water. The aerosol causes apparent negative non-sea-salt sulphate in ice cores because of fractionation during freezing. This implies that the reality is diametrically opposed to the traditional view: increased sea salt in ice cores is associated with more sea ice, and more freshly freezing areas within the ice pack with light winds. This sea ice origin of sea salt aerosol via frost flowers would make sense of the observation that the flux of sea salt to ice cores is larger during glacial periods than warm periods. Frost flowers are also almost certainly responsible for surface ozone loss in spring by production of reactive bromine gases from the flowers or their aerosol. Our understanding of these complex processes is vital if we are to fully account for past and future polar environmental changes. We must also parameterise them so that we can model the changes, but at present there is no complete parameterisation of either the formation of frost flowers or their dispersal into the atmosphere as aerosol. Here, we will measure the physics and chemistry of frost flower growth and the dispersal of their aerosol in the laboratory, and proceed to parameterisation of the processes involved.