Collaborative Research: VOCALS--Interaction of Aerosols with Marine Boundary Layer Clouds

这项研究将侧重于2008年VAMOS海洋-云-大气-陆地研究区域实验(VAMOS海洋-云-大气-陆地研究区域实验)项目期间从NSF C-130飞机在东南太平洋(SEP)上空获得的环境气溶胶和残余云滴核的物理和化学分析。这项工作解决了下列声学假设：1)气溶胶性质的变异性影响层积云中毛毛雨的形成，2)SEP上的小气溶胶半径主要由人为的而不是自然的气溶胶生产控制，来自自由对流层低层的污染空气的夹带是云凝结核(CCN)的重要来源，以及3)海洋上涌影响气溶胶前体气体和SEP上方大气边界层中的气溶胶尺寸分布。为了探索这些假设，将在使用逆流虚拟撞击器(CVI)采样后测量云滴中剩余核的大小和化学成分，CVI将液滴从间隙气溶胶中分离并蒸发。云外的气溶胶将用冲击器进行采样。剩余核和周围气溶胶的过滤器和撞击器样品将通过电子显微镜和X射线分析进行分析。这些数据将与云微物理测量相结合，以确定气溶胶对云的光学性质和寿命的影响，以及形成云滴的气溶胶粒子的特征。还将探索引发毛毛雨产生的较大液滴的核。这些测量将补充其他研究人员在声乐方面的观察结果。这项工作将有助于深入了解人类活动产生的气溶胶如何影响降水以及云对地球气候的辐射影响。教育计划包括一名本科生和博士后学者，他们将与调查人员合作，分析和解释收集的数据。

This study will focus on physical and chemical analysis of ambient aerosol and residual cloud droplet nuclei obtained from the NSF C-130 aircraft over the southeast Pacific (SEP) during the 2008 VOCALS-REx (VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment) project. This work addresses the following VOCALS hypotheses: 1) Variability in aerosol properties impacts the formation of drizzle in stratocumulus clouds over the SEP, 2) The small aerosol radii over the SEP are primarily controlled by anthropogenic, rather than natural, aerosol production, and entrainment of polluted air from the lower free troposphere is an important source of cloud condensation nuclei (CCN), and 3) Ocean upwelling affects aerosol precursor gases and the aerosol size distribution in the atmospheric boundary layer over the SEP. To explore these hypotheses, the size and chemical composition of residual nuclei in cloud droplets will be measured following sampling with a counterflow virtual impactor (CVI), which separates droplets from interstitial aerosol and evaporates them. Aerosols outside of clouds will be sampled with an impactor. Filter and impactor samples of residual nuclei and ambient aerosol will be analyzed by electron microscopy with X-ray analysis. These data will be combined with cloud microphysical measurements to determine aerosol effects on cloud optical properties and lifetimes and the characteristics of aerosol particles that nucleate cloud droplets. Nuclei of larger droplets, which initiate drizzle production, will also be explored. These measurements will complement observations being made by other investigators in VOCALS. This work will lead to insight into how aerosol production due to human activity influences precipitation and the radiative impact of clouds on Earth's climate. The educational plans include an undergraduate student and postdoctoral scholar who will work with the investigators to analyze and interpret the data collected.