AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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Recent Findings from Airborne Cloud Water Measurements off the Western United States Coast
ARMIN SOROOSHIAN, Zhen Wang, Hossein Dadashazar, Alex MacDonald, Ewan Crosbie, Haflidi Jonsson, Richard Flagan, John Seinfeld, University of Arizona
Abstract Number: 42 Working Group: There Must be Something in the Water: Cloud, Fog and Aerosol Aqueous Chemistry for Aerosol Production
Abstract Clouds play several critical roles in the atmosphere including being a key agent in radiative forcing, the hydrological cycle, transferring nutrients and contaminants from one area to another via in-cloud scavenging and eventual rainout, and chemical transformations of gases and particles. Quantifying the nature and magnitude of each of these cloud processes is challenging owing to the difficulty of obtaining measurements at sufficiently fine temporal and spatial scales. Application of chemical tracers presents a potentially effective means to identify emissions sources, dynamical processes, and chemical conversion processes impacting clouds. Of interest in this work are marine stratocumulus clouds, which are the dominant cloud type by global area, exerting a strong negative net radiative effect.
This presentation will report on findings based on cloud water measurements conducted over multiple field campaigns between 2011 and 2016 off the US western coast using the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter. Results to be discussed relate to the relative abundance of non-water dissolved species in cloud water as a function of factors such as altitude in cloud, the degree of coupling of clouds to the surface layer, and air mass source. In these campaigns a suite of carboxylic acids were speciated and quantified in both cloud water and droplet residual particles. Their characteristics, including relationships with metals, will be discussed.