Airborne Studies of Ocean-Particle-Cloud Interactions in the Arctic

本项目是利用激光雷达和多频辐射计远程探测北极海冰中铅的物理特性，以及海洋中二甲硫化物（DMS）的排放对云凝结核（CCN）的影响，北极雾霾和层云的结构和辐射特性的空中实地调查。该项目将使用华盛顿大学拥有的C-131飞机，并将成为北极铅动力学实验（LEADEX）和北极气体和气溶胶采样计划（agaspiv）的组成部分。虽然海冰覆盖的开阔水域仅占北冰洋的百分之几，但它们在向大气传递热量的湍流和挥发性生物物质的传递中发挥着重要作用。该项目将集中研究海洋DMS的通量，DMS是大气硫收支的重要贡献者，通过氧化生成二氧化硫和硫酸盐，是海洋大气中云凝结核的主要来源。首席研究员还将研究DMS对北极雾霾的影响，这是一种在各种北极过程中被认为是重要的大气现象。它通过改变云顶的反照率和热红外通量直接影响辐射收支，通过云凝结核对云辐射特性的调制作用间接影响辐射收支。如果能够证明当地云凝结核浓度取决于DMS排放，就有可能确定对北极海洋平流层反照率的生物控制。也可能是北极雾霾中沉积的微量元素为敏感的北极生态系统贡献了大量的污染物通量。

This project is an airborne field investigation of the physical characteristics of leads in arctic sea ice using a lidar and multi- frequency radiometers to remotely probe the ice surface, as well as of the emission of dimethylsulfide (DMS) from the ocean of its effects on cloud condensation nuclei (CCN), the structure and radiative properties of arctic haze and stratus clouds. The project will make use of an instrumented C-131 aircraft owned by the University of Washington, and will be a component of the Arctic Lead Dynamics Experiment (LEADEX) and the Arctic Gas and Aerosol Sampling Program (AGASP-IV). Although leads, or areas of open water in the sea ice cover, account for only a few percent of the Arctic Ocean, they play a major role in the turbulent transfer of heat to the atmosphere, and in the transfer of volatile biogenic material. This project will concentrate on the flux of oceanic DMS, which is an important contributor to the atmospheric sulfur budget and, through oxidation to sulfur dioxide and sulfates, is a primary source of cloud condensation nuclei in the marine atmosphere. The principal investigator will also study the effect of DMS on arctic haze, which is an atmospheric phenomenon considered to be important in a variety of arctic processes. It affects the radiation budget directly by modifying the albedo and the thermal infra-red flux at cloud top levels, and indirectly through the modulation effect on cloud radiative properties by cloud condensation nuclei. If it can be shown that local Cloud Condensation Nuclei concentrations depend upon DMS emissions, it may be possible to identify a biological control of the arctic marine stratus albedo. It may also be that deposited trace elements from arctic haze contribute significant fluxes of contaminants to sensitive arctic ecosystems.