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，南极臭氧层空洞、南极半岛气温大幅上升和北冰洋海冰消失都表明了这一点。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，风越大，海盐是由风对开放的海洋水域产生的。然而，现在人们认为，极地地区的海盐气溶胶主要来自冰盖内的海冰表面，包括霜花，而不是来自开阔的水域。由于冰冻过程中的分馏作用，气溶胶在冰芯中产生明显的负值非海盐硫酸盐。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，冰包内更多的新鲜冰冻区域伴随着微风。这种通过霜花形成海盐气溶胶的海冰可以解释这样一种观察，即在冰川时期，海盐流向冰芯的通量比暖期更大。霜花几乎肯定也是春季地表臭氧损失的罪魁祸首，因为它们会从花或其气溶胶中产生活性溴气体。如果我们要充分考虑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，这样我们才能对变化进行模拟，但目前还没有对霜花的形成或它们作为气溶胶扩散到大气中的完全参数化。在这里，我们将在实验室中测量霜花生长和它们的气溶胶扩散的物理和化学，并继续对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.