SGER: Parameterization of Sea-Salt Cloud Condensation Nuclei (CCN) Production for 3-D Earth System Models

最近的调查的基础上测量的气溶胶在环境空气中提供的证据表明，膜下降从海洋表面上爆裂的气泡产生高浓度的初级，亚微米，有机物丰富的气溶胶与云的特性和气候反馈的潜在重要影响。如果在海洋表面破裂的气泡是一个主要的吸湿性，有机物丰富，亚微米气溶胶在世界海洋的主要来源，那么目前的模式，不考虑这些途径可能会大大高估气溶胶成核的重要性作为云凝结核（CCN）和相关的间接气候强迫的来源。然而，亚微米气溶胶的长寿命（许多天）加上新鲜海洋气溶胶的快速化学转化（秒），严重限制了可靠的区分的基础上测量环境空气中的有机贡献的主要（机械）与次要（冷凝）的途径，涉及海洋，人为和生物的前体。该项目是一项关于海盐气溶胶对大气化学和气候影响的更大规模（已经在进行中）调查的一个组成部分。更大规模研究工作的总体目标是评估1）卤素自由基对对流层O3、氧化硫、活性氮和相应氧化能力的影响，以及2）初级海洋气溶胶作为云凝结核（CCN）的相对重要性。该SGER项目的主要目标是：开发一种可靠的参数化方法，用于确定主要尺寸分辨海洋气溶胶的化学和物理特性，作为风速和表层海洋溶解有机碳（DOC）含量的函数，适用于共同体气候系统模式（CCSM）和其他全球模式系统。完成这项工作是CCSM优先发展可靠的气溶胶云参数化以解决气溶胶间接影响的关键先决条件。更广泛的影响。该项目将为一名研究生提供支持，并将分析纳入他的论文。研究结果还将有助于发展可靠的预测能力，预测对流层气溶胶的产生和间接辐射效应以及对地球气候的相关影响。

Recent investigations based on measurements of aerosols in ambient air provide evidence that film drops from bursting bubbles on the ocean surface produce high concentrations of primary, sub-micron, organic-rich aerosols with potentially important implications for cloud properties and climate feedback. If bursting bubbles on the ocean surface are a major primary source for hygroscopic, organic-rich, sub-micron aerosol over the world's oceans, then current models that do not consider these pathways may substantially overestimate both the importance of aerosol nucleation as a source for cloud condensation nuclei (CCN) and the associated indirect climate forcing. However, the long lifetimes of sub-micron aerosols (many days) coupled with the rapid chemical transformation of fresh marine aerosols (seconds), seriously constrain reliable differentiation based on measurements in ambient air of organic contributions from primary (mechanical) versus secondary (condensation) pathways involving marine, anthropogenic, and biogenic precursors. This project is one component of a larger (already ongoing) investigation of the influence of sea-salt aerosol on atmospheric chemistry and climate. The overall goals of the larger research effort are to evaluate 1) the influences of halogen radicals on tropospheric O3, oxidized S, reactive N, and corresponding oxidative capacity and 2) the relative importance of primary marine aerosol as cloud condensation nuclei (CCN). The principal objective of this SGER project is: To develop a reliable parameterization for the chemical and physical characteristics of primary size-resolved marine aerosol as functions of wind velocity and dissolved organic carbon (DOC) content of the surface ocean that is suitable for application in the Community Climate System Model (CCSM) and other global model systems. Completion of this effort is a critical prerequisite for the CCSM priority of developing reliable aerosol-cloud parameterizations to address the indirect effect of aerosols. Broader Impacts. This project will provide support for one graduate student and the analysis will be incorporated into his dissertation. Results will also contribute to the development of a reliable predictive capability for the production and indirect radiative effects of tropospheric aerosols and the associated influences on Earth's climate.