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Title: Characteristic Vertical Profiles of Cloud Water Composition in Marine Stratocumulus Clouds and Relationships With Precipitation

Abstract

This study uses airborne cloud water composition measurements to characterize the vertical structure of air-equivalent mass concentrations of water-soluble species in marine stratocumulus clouds off the California coast. A total of 385 cloud water samples were collected in the months of July and August between 2011 and 2016 and analyzed for water-soluble ionic and elemental composition. Three characteristic profiles emerge: (i) a reduction of concentration with in-cloud altitude for particulate species directly emitted from sources below cloud without in-cloud sources (e.g., Cl-, Na+); (ii) an increase of concentration with in-cloud altitude (e.g., NO2-, formate); and (iii) species exhibiting a peak in concentration in the middle of cloud (e.g., non-sea salt SO42-, NO3-, organic acids). Vertical profiles of rainout parameters such as loss frequency, lifetime, and change in concentration with respect to time show that the scavenging efficiency throughout the cloud depth depends strongly on the thickness of the cloud. Thin clouds exhibit a greater scavenging loss frequency at cloud top, while thick clouds have a greater scavenging loss frequency at cloud base. The implications of these results for treatment of wet scavenging in models are discussed.

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3]; ORCiD logo [4]; ORCiD logo [1]; ORCiD logo [5]; ORCiD logo [6]; ORCiD logo [6]; ORCiD logo [7]
  1. Department of Chemical and Environmental Engineering, University of Arizona, Tucson AZ USA
  2. Earth and Planetary Sciences, University of California, Santa Cruz CA USA
  3. Science Systems and Applications, Inc., Hampton VA USA; NASA Langley Research Center, Hampton VA USA
  4. Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland WA USA
  5. Department of Meteorology, Naval Postgraduate School, Monterey CA USA
  6. Department of Chemical Engineering, California Institute of Technology, Pasadena CA USA
  7. Department of Chemical and Environmental Engineering, University of Arizona, Tucson AZ USA; Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson AZ USA
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1439004
Report Number(s):
PNNL-SA-133226
Journal ID: ISSN 2169-897X; KP1703020
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Geophysical Research: Atmospheres; Journal Volume: 123; Journal Issue: 7
Country of Publication:
United States
Language:
English
Subject:
cloud water; Stratocumulus; scavenging; rainout; sea salt; aerosol

Citation Formats

MacDonald, Alexander B., Dadashazar, Hossein, Chuang, Patrick Y., Crosbie, Ewan, Wang, Hailong, Wang, Zhen, Jonsson, Haflidi H., Flagan, Richard C., Seinfeld, John H., and Sorooshian, Armin. Characteristic Vertical Profiles of Cloud Water Composition in Marine Stratocumulus Clouds and Relationships With Precipitation. United States: N. p., 2018. Web. doi:10.1002/2017JD027900.
MacDonald, Alexander B., Dadashazar, Hossein, Chuang, Patrick Y., Crosbie, Ewan, Wang, Hailong, Wang, Zhen, Jonsson, Haflidi H., Flagan, Richard C., Seinfeld, John H., & Sorooshian, Armin. Characteristic Vertical Profiles of Cloud Water Composition in Marine Stratocumulus Clouds and Relationships With Precipitation. United States. doi:10.1002/2017JD027900.
MacDonald, Alexander B., Dadashazar, Hossein, Chuang, Patrick Y., Crosbie, Ewan, Wang, Hailong, Wang, Zhen, Jonsson, Haflidi H., Flagan, Richard C., Seinfeld, John H., and Sorooshian, Armin. Fri . "Characteristic Vertical Profiles of Cloud Water Composition in Marine Stratocumulus Clouds and Relationships With Precipitation". United States. doi:10.1002/2017JD027900.
@article{osti_1439004,
title = {Characteristic Vertical Profiles of Cloud Water Composition in Marine Stratocumulus Clouds and Relationships With Precipitation},
author = {MacDonald, Alexander B. and Dadashazar, Hossein and Chuang, Patrick Y. and Crosbie, Ewan and Wang, Hailong and Wang, Zhen and Jonsson, Haflidi H. and Flagan, Richard C. and Seinfeld, John H. and Sorooshian, Armin},
abstractNote = {This study uses airborne cloud water composition measurements to characterize the vertical structure of air-equivalent mass concentrations of water-soluble species in marine stratocumulus clouds off the California coast. A total of 385 cloud water samples were collected in the months of July and August between 2011 and 2016 and analyzed for water-soluble ionic and elemental composition. Three characteristic profiles emerge: (i) a reduction of concentration with in-cloud altitude for particulate species directly emitted from sources below cloud without in-cloud sources (e.g., Cl-, Na+); (ii) an increase of concentration with in-cloud altitude (e.g., NO2-, formate); and (iii) species exhibiting a peak in concentration in the middle of cloud (e.g., non-sea salt SO42-, NO3-, organic acids). Vertical profiles of rainout parameters such as loss frequency, lifetime, and change in concentration with respect to time show that the scavenging efficiency throughout the cloud depth depends strongly on the thickness of the cloud. Thin clouds exhibit a greater scavenging loss frequency at cloud top, while thick clouds have a greater scavenging loss frequency at cloud base. The implications of these results for treatment of wet scavenging in models are discussed.},
doi = {10.1002/2017JD027900},
journal = {Journal of Geophysical Research: Atmospheres},
number = 7,
volume = 123,
place = {United States},
year = {Fri Apr 13 00:00:00 EDT 2018},
month = {Fri Apr 13 00:00:00 EDT 2018}
}