Collaborative Research: Contrasting the Effects of Aerosols on Marine Boundary Layer (MBL) Cloud-precipitation Properties and Processes in Boreal and Austral Mid-latitude Regions

该项目是为了研究海洋边界层云的形成，这是一种直接受海洋影响的云。尤其是微小的悬浮颗粒或气溶胶如何形成云，以及云如何与气溶胶相互作用。气溶胶是由大气、陆地和海洋过程产生的，如城市/工业活动、沙尘暴、燃烧的植被、生物活动、海雾、风流和火山。某些气溶胶类型比其他类型更容易引发海洋边界层云的发展。这增加了海洋边界层云对天气变化的影响的复杂性和不确定性。海洋边界层云对水文循环和地球辐射平衡有重要的气候影响。例如，全球海洋边界层云的不同分布导致太阳能和降雨量出现赤字和盈余。在全球大部分人口和陆地所在的北半球，已经进行了许多关于气溶胶-云相互作用的研究。关于南半球广阔的偏远陆地和海洋地区，人们所知的并不多。这项研究将通过分析最近的野外观测和利用数值模式模拟来研究南北半球之间气溶胶-云相互作用的异同。该项目邀请本科生和研究生参与研究项目，并将他们培训为下一代科学家。这项研究使用了从北大西洋东部专用观测点进行的长期地面观测和遥感反演，以及2018年两个密集野外活动的飞机现场测量：1)北大西洋东部气溶胶和云实验(ACE-ENA)，2)南大洋云、辐射、气溶胶输送实验研究(苏格拉底)。研究小组利用协同测量/模拟方法与气象模式相结合，通过回答三个科学问题来比较两个半球的海洋边界层气溶胶、云和毛毛雨的特征。它们是：1)地面云凝结核和上升气流在海洋边界层气溶胶-云相互作用和暖雨过程中的相对作用；2)海洋边界层气溶胶、云和毛毛雨特性及其相互作用的特征；3)南大洋海洋边界层气溶胶、云和毛毛雨特性的特征、它们的相互作用及其与东北大西洋东部的异同？对两个环境条件明显不同的地点的降水过程和气溶胶-云相互作用的比较将有助于揭示气溶胶-云相互作用的控制因素，并最终导致适用于全球气候模式的气溶胶-云相互作用的通用参数化。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The project is to investigate formation of marine-boundary-layer clouds, which are clouds that are directly influenced by the ocean. Particularly, how tiny suspended particles or aerosols contribute to clouds and how clouds interact with aerosols. Aerosols are generated from atmospheric, land, and oceanic processes such as urban/industrial activity, dust storms, burning vegetation, biological activity, sea spray, wind currents, and volcanoes. Certain aerosol types can initiate marine-boundary-layer cloud development more easily than others. This adds to the complexity and uncertainty of marine-boundary-layer cloud impacts on weather variations. Marine-boundary-layer clouds have significant climatological effects on the hydrological cycle and the Earth’s radiation balance. For example, varying distributions of marine-boundary-layer clouds around the globe contribute to areas of deficits and surpluses in solar energy and rainfall. Many studies have been conducted on aerosol-cloud interactions in the Northern Hemisphere where most of the global population and landmasses are located. Not much is known over the vast area of remote land and oceanic regions in the Southern Hemisphere. This study will investigate differences and similarities of aerosol-cloud interactions between the Northern and Southern Hemispheres by analyzing recent field observations and utilizing numerical model simulations. The project involves undergraduate and graduate students to participate in the research project and train them to be the next generation of scientists.This study employs long-term ground-based observations and remote sensing retrievals from a dedicated observation site in the Eastern North Atlantic Ocean and aircraft in situ measurements from two intensive field campaigns in 2018: 1) the Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA), and 2) the Southern Ocean Clouds, Radiation, Aerosol Transport Experimental Study (SOCRATES). The research team utilizes a synergistic measurement/modeling approach in conjunction with meteorological patterns to compare the characteristics of marine-boundary-layer aerosol, cloud, and drizzle properties over the two hemispheres through answering three scientific questions. Those are: 1) what are the relative roles of surface cloud condensation nuclei and updrafts in aerosol-cloud interactions over the marine boundary layer and warm rain processes? 2) what are the characteristics of marine-boundary-layer aerosol, cloud and drizzle properties and their interactions during two field campaigns? 3) what are the characteristics of marine-boundary-layer aerosol, cloud, and drizzle properties, their interactions over the Southern Ocean, and their similarities and differences compared with those in the Eastern North Atlantic Ocean? Comparisons of precipitation processes and aerosol-cloud interactions at the two sites with significantly different environmental conditions will shed light on the controlling factors in aerosol-cloud interactions and eventually lead to a generalized parameterization for aerosol-cloud interactions applicable for the global climate models.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.