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Title: A long-term study of aerosol–cloud interactions and their radiative effect at the Southern Great Plains using ground-based measurements

Abstract

Empirical estimates of the microphysical response of cloud droplet size distribution to aerosol perturbations are commonly used to constrain aerosol–cloud interactions in climate models. Instead of empirical microphysical estimates, here macroscopic variables are analyzed to address the influence of aerosol particles and meteorological descriptors on instantaneous cloud albedo and the radiative effect of shallow liquid water clouds. Long-term ground-based measurements from the Atmospheric Radiation Measurement (ARM) program over the Southern Great Plains are used. A broad statistical analysis was performed on 14 years of coincident measurements of low clouds, aerosol, and meteorological properties. Here two cases representing conflicting results regarding the relationship between the aerosol and the cloud radiative effect were selected and studied in greater detail. Microphysical estimates are shown to be very uncertain and to depend strongly on the methodology, retrieval technique and averaging scale. For this continental site, the results indicate that the influence of the aerosol on the shallow cloud radiative effect and albedo is weak and that macroscopic cloud properties and dynamics play a much larger role in determining the instantaneous cloud radiative effect compared to microphysical effects. On a daily basis, aerosol shows no correlation with cloud radiative properties (correlation = -0.01 ± 0.03),more » whereas the liquid water path shows a clear signal (correlation = 0.56 ± 0.02).« less

Authors:
 [1];  [2];  [3]
  1. Univ. of Sao Paulo, Sao Paulo (Brazil); NOAA Chemical Sciences Division, Boulder, CO (United States)
  2. NOAA Global Monitoring Division, Boulder, CO (United States)
  3. NOAA Chemical Sciences Division, Boulder, CO (United States)
Publication Date:
Research Org.:
National Oceanic and Atmospheric Administration, Boulder, CO (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1364422
Grant/Contract Number:
SC0014568
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Atmospheric Chemistry and Physics (Online)
Additional Journal Information:
Journal Name: Atmospheric Chemistry and Physics (Online); Journal Volume: 16; Journal Issue: 17; Journal ID: ISSN 1680-7324
Publisher:
European Geosciences Union
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES

Citation Formats

Sena, Elisa T., McComiskey, Allison, and Feingold, Graham. A long-term study of aerosol–cloud interactions and their radiative effect at the Southern Great Plains using ground-based measurements. United States: N. p., 2016. Web. doi:10.5194/acp-16-11301-2016.
Sena, Elisa T., McComiskey, Allison, & Feingold, Graham. A long-term study of aerosol–cloud interactions and their radiative effect at the Southern Great Plains using ground-based measurements. United States. doi:10.5194/acp-16-11301-2016.
Sena, Elisa T., McComiskey, Allison, and Feingold, Graham. Tue . "A long-term study of aerosol–cloud interactions and their radiative effect at the Southern Great Plains using ground-based measurements". United States. doi:10.5194/acp-16-11301-2016. https://www.osti.gov/servlets/purl/1364422.
@article{osti_1364422,
title = {A long-term study of aerosol–cloud interactions and their radiative effect at the Southern Great Plains using ground-based measurements},
author = {Sena, Elisa T. and McComiskey, Allison and Feingold, Graham},
abstractNote = {Empirical estimates of the microphysical response of cloud droplet size distribution to aerosol perturbations are commonly used to constrain aerosol–cloud interactions in climate models. Instead of empirical microphysical estimates, here macroscopic variables are analyzed to address the influence of aerosol particles and meteorological descriptors on instantaneous cloud albedo and the radiative effect of shallow liquid water clouds. Long-term ground-based measurements from the Atmospheric Radiation Measurement (ARM) program over the Southern Great Plains are used. A broad statistical analysis was performed on 14 years of coincident measurements of low clouds, aerosol, and meteorological properties. Here two cases representing conflicting results regarding the relationship between the aerosol and the cloud radiative effect were selected and studied in greater detail. Microphysical estimates are shown to be very uncertain and to depend strongly on the methodology, retrieval technique and averaging scale. For this continental site, the results indicate that the influence of the aerosol on the shallow cloud radiative effect and albedo is weak and that macroscopic cloud properties and dynamics play a much larger role in determining the instantaneous cloud radiative effect compared to microphysical effects. On a daily basis, aerosol shows no correlation with cloud radiative properties (correlation = -0.01 ± 0.03), whereas the liquid water path shows a clear signal (correlation = 0.56 ± 0.02).},
doi = {10.5194/acp-16-11301-2016},
journal = {Atmospheric Chemistry and Physics (Online)},
number = 17,
volume = 16,
place = {United States},
year = {Tue Sep 13 00:00:00 EDT 2016},
month = {Tue Sep 13 00:00:00 EDT 2016}
}

Journal Article:
Free Publicly Available Full Text
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Cited by: 1work
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  • In this study the long-term trends of non-refractory submicrometer aerosol (NR-PM1) composition and mass concentration measured by an Aerosol Chemical Speciation Monitor (ACSM) at the U.S. Department of Energy’s Southern Great Plains (SGP) site are discussed. Over the period of 19 months (Nov. 20, 2010 – June 2012) highly time resolved (~30 min.) NR-PM1 data was recorded. Using this dataset the value-added product (VAP) of deriving organic aerosol components (OACOMP) is introduced. With this VAP, multivariate analysis of the measured organic mass spectral matrix can be performed on long term data to return organic aerosol (OA) factors that are associatedmore » with distinct sources, evolution processes, and physiochemical properties. Three factors were obtained from this VAP including two oxygenated OA (OOA) factors, differing in degrees of oxidation, and a biomass burning OA (BBOA) factor. Back trajectory analyses were performed to investigate possible sources of major NR-PM1 species at the SGP site. Organics dominated NR-PM1 mass concentration for the majority of the study with the exception of winter, when nitrate increased due to transport of precursor species from surrounding urban and agricultural areas and also due to cooler temperatures. Sulfate mass concentrations showed little seasonal variation with mixed regional and local sources. In the spring BBOA emissions increased and were mainly associated with local fires. Isoprene and carbon monoxide emission rates were computed by the Model of Emissions of Gases and Aerosols from Nature (MEGAN) to represent the spatial distribution of biogenic and anthropogenic sources, respectively. From this model there is evidence to support that biogenic emissions from the southeast contribute to SOA formation at the SGP site during the summer.« less
  • In this study the long-term trends of non-refractory submicrometer aerosol (NR-PM1) composition and mass concentration measured by an Aerosol Chemical Speciation Monitor (ACSM) at the Atmospheric Radiation Measurement (ARM) program's Southern Great Plains (SGP) site are discussed. NR-PM1 data was recorded at ~30 min intervals over a period of 19 months between November 2010 and June 2012. Positive Matrix Factorization (PMF) was performed on the measured organic mass spectral matrix using a rolling window technique to derive factors associated with distinct sources, evolution processes, and physiochemical properties. The rolling window approach also allows us to capture the dynamic variations ofmore » the chemical properties in the organic aerosol (OA) factors over time. Three OA factors were obtained including two oxygenated OA (OOA) factors, differing in degrees of oxidation, and a biomass burning OA (BBOA) factor. Back trajectory analyses were performed to investigate possible sources of major NR-PM1 species at the SGP site. Organics dominated NR-PM1 mass concentration for the majority of the study with the exception of winter, when ammonium nitrate increases due to transport of precursor species from surrounding urban and agricultural areas and also due to cooler temperatures. Sulfate mass concentrations have little seasonal variation with mixed regional and local sources. In the spring BBOA emissions increase and are mainly associated with local fires. Isoprene and carbon monoxide emission rates were obtained by the Model of Emissions of Gases and Aerosols from Nature (MEGAN) and the 2011 U.S. National Emissions Inventory to represent the spatial distribution of biogenic and anthropogenic sources, respectively. The combined spatial distribution of isoprene emissions and air mass trajectories suggest that biogenic emissions from the southeast contribute to SOA formation at the SGP site during the summer.« less
  • A 25-month database of the macrophysical, microphysical, and radiative properties of isolated and overcast low-level stratus clouds has been generated using a newly developed parameterization and surface measurements from the Atmospheric Radiation Measurement central facility in Oklahoma. The database (5-min resolution) includes two parts: measurements and retrievals. The former consist of cloud base and top heights, layer-mean temperature, cloud liquid water path, and solar transmission ratio measured by a ground-based lidar/ceilometer and radar pair, radiosondes, a microwave radiometer, and a standard Eppley precision spectral pyranometer, respectively. The retrievals include the cloud-droplet effective radius and number concentration and broadband shortwave opticalmore » depth and cloud and top-of-atmosphere albedos. Stratus without any overlying mid or high-level clouds occurred most frequently during winter and least often during summer. Mean cloud-layer altitudes and geometric thicknesses were higher and greater, respectively, in summer than in winter. Both quantities are positively correlated with the cloud-layer mean temperature. Mean cloud-droplet effective radii range from 8.1 {mu}m in winter to 9.7 {mu}m during summer, while cloud-droplet number concentrations during winter are nearly twice those in summer. Since cloud liquid water paths are almost the same in both seasons, cloud optical depth is higher during the winter, leading to greater cloud albedos and lower cloud transmittances. (c) 2000 American Geophysical Union.« less
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