Sources, Visibility and Climate Effects of Marine Aerosols

液态云和雾滴，就像沸水产生的蒸汽，是在大气中预先存在的气溶胶颗粒上形成的，颗粒的大小和化学成分影响它们变成液滴的能力。粒子的数量可以影响云或雾的反射率，从而影响雾中的能见度或透过云的阳光的比例，从而影响地球的能量收支。然而，粒子、云和气候之间的联系仍然很不明确。海洋，包括沿海和极地地区，覆盖了地球的70%，但我们对它们排放到大气中的颗粒和颗粒前体（即气体）的了解仍然高度不确定，海洋颗粒通过云和雾的形成对气候和能见度的最终影响也是如此。为了解决这个问题，拟议的工作将使用各种技术来1)确定海洋表面化学和物理条件如何在受控的实验室环境中影响海洋气溶胶颗粒的性质，并通过模拟研究将这些发现应用于海洋大气环境；2)通过扩展的众包观测网络和详细的观测研究，在加拿大北部沿海地区测试雾的形成和能见度预测；3)通过实地和模拟研究，确定颗粒化学和物理性质对雾/云性质（如雾滴浓度、能见度和反射率）的影响程度，从而限制海洋地区气溶胶-雾/云的相互作用。总的来说，这项研究将提高我们对海洋、沿海和极地气溶胶的来源和特性的理解，以及它们通过激活云滴的能力对气候的影响。预计这项工作将通过改进雾预报，直接惠及沿海居民，特别是北方居民。这项工作还将通过改进初级和次级海洋气溶胶的特征，使化学输送建模者受益，并通过提供样本数据集来比较他们对气溶胶-云相互作用的模拟，从而使气候建模者受益。

Liquid cloud and fog droplets, like steam from boiling water, form on pre-existing aerosol particles in the atmosphere, and the particle size and chemical composition affect their ability to turn into droplets. The number of particles can affect the reflectivity of a cloud or fog, which affects visibility in a fog or the fraction of sunlight transmitted through a cloud, thus affecting the Earth's energy budget. However, the link between particles, clouds and climate remains poorly constrained. The oceans, including coastal and polar regions, cover 70% of the Earth yet our understanding of the particles and particle precursors (i.e. gases) that they emit into the atmosphere are still highly uncertain as are the ultimate effect of marine particles on climate and visibility through cloud and fog formation. To address this, the proposed work will use a variety of techniques to 1) determine how surface ocean chemical and physical conditions affect the properties of marine aerosol particles in controlled laboratory settings and apply these findings to the ambient marine atmosphere through modelling studies; 2) test fog formation and visibility predictions at northern Canadian coastal locations through an extended crowd-sourced observation network and detailed observational studies; and 3) constrain aerosol-fog/cloud interactions in marine locations by determining the extent to which particle chemical and physical properties affect fog/cloud properties such as droplet concentration, visibility and reflectivity through field and modelling studies. Taken together, this research will improve our understanding of the sources and properties of marine, coastal, and polar aerosols as well as their impact on climate through their ability to activate as cloud droplets. It is expected that this work will directly benefit coastal residents, especially those living in the North, through improved fog predictions. This work will also benefit chemical transport modellers through improved characterization of primary and secondary marine aerosols, and climate modellers by providing sample data sets against which their simulations of aerosol-cloud interactions can be compared.