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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

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:
Grant/Contract Number:
SC0014568
Type:
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
Research Org:
National Oceanic and Atmospheric Administration, Boulder, CO (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES
OSTI Identifier:
1364422