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

霜花及其生成的海盐气溶胶的物理和化学

• 批准号: NE/D004543/1
• 负责人: Michael Smith
• 金额: $ 15.71万
• 依托单位: British Antarctic Survey
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FD004543%2F1
• 关键词: Physics; Chemistry; Frost; Flowers; Their

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.

极地地区是环境因素对全球气候影响的有力指标，南极臭氧空洞、南极半岛气温大幅上升以及北极海冰消失就表明了这一点。冰芯记录还可以为过去的气候变化提供有力的记录，只要它们能够被准确地解释。传统上，人们认为冰芯中海盐浓度越高，表明海冰越少，风就越强，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冰袋内的海冰表面产生的，包括霜花，而不是开放水域。由于冻结过程中的分馏，气溶胶会在冰芯中产生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以及微风下冰袋内更多新结冰的区域有关。海盐气溶胶通过霜花的海冰起源使得观察到的现象有意义，即冰期期间海盐到冰芯的通量比温暖时期更大。几乎可以肯定，霜花也会因花朵或其气溶胶产生活性溴气体而导致春季表面臭氧损失。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至关重要。我们还必须对它们进行参数化，以便我们能够对变化进行建模，但目前还没有对霜花的形成或其作为气溶胶扩散到大气中的完整参数化。在这里，我们将在实验室中测量霜花生长的物理和化学及其气溶胶的扩散，并继续对所涉及的过程进行参数化。