The interdependence of continental warm cloud properties derived from unexploited solar background signals in ground-based lidar measurements

We have extensively analysed the interdependence between cloud optical depth, droplet effective radius, liquid water path (LWP) and geometric thickness for stratiform warm clouds using ground-based observations. In particular, this analysis uses cloud optical depths retrieved from untapped solar bac...

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Main Authors: J. C. Chiu, J. A. Holmes, R. J. Hogan, E. J. O'Connor
Format: Article
Language:English
Published: Copernicus Publications 2014-08-01
Series:Atmospheric Chemistry and Physics
Online Access:http://www.atmos-chem-phys.net/14/8389/2014/acp-14-8389-2014.pdf
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author J. C. Chiu
J. A. Holmes
R. J. Hogan
E. J. O'Connor
author_facet J. C. Chiu
J. A. Holmes
R. J. Hogan
E. J. O'Connor
author_sort J. C. Chiu
collection DOAJ
description We have extensively analysed the interdependence between cloud optical depth, droplet effective radius, liquid water path (LWP) and geometric thickness for stratiform warm clouds using ground-based observations. In particular, this analysis uses cloud optical depths retrieved from untapped solar background signals that are previously unwanted and need to be removed in most lidar applications. Combining these new optical depth retrievals with radar and microwave observations at the Atmospheric Radiation Measurement (ARM) Climate Research Facility in Oklahoma during 2005–2007, we have found that LWP and geometric thickness increase and follow a power-law relationship with cloud optical depth regardless of the presence of drizzle; LWP and geometric thickness in drizzling clouds can be generally 20–40% and at least 10% higher than those in non-drizzling clouds, respectively. In contrast, droplet effective radius shows a negative correlation with optical depth in drizzling clouds and a positive correlation in non-drizzling clouds, where, for large optical depths, it asymptotes to 10 μm. This asymptotic behaviour in non-drizzling clouds is found in both the droplet effective radius and optical depth, making it possible to use simple thresholds of optical depth, droplet size, or a combination of these two variables for drizzle delineation. This paper demonstrates a new way to enhance ground-based cloud observations and drizzle delineations using existing lidar networks.
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spelling doaj.art-0797418bf12f46549540ca4ae0d962a02022-12-22T03:22:53ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242014-08-0114168389840110.5194/acp-14-8389-2014The interdependence of continental warm cloud properties derived from unexploited solar background signals in ground-based lidar measurementsJ. C. Chiu0J. A. Holmes1R. J. Hogan2E. J. O'Connor3Department of Meteorology, University of Reading, Reading, UKDepartment of Physical Sciences, Open University, Milton Keynes, UKDepartment of Meteorology, University of Reading, Reading, UKDepartment of Meteorology, University of Reading, Reading, UKWe have extensively analysed the interdependence between cloud optical depth, droplet effective radius, liquid water path (LWP) and geometric thickness for stratiform warm clouds using ground-based observations. In particular, this analysis uses cloud optical depths retrieved from untapped solar background signals that are previously unwanted and need to be removed in most lidar applications. Combining these new optical depth retrievals with radar and microwave observations at the Atmospheric Radiation Measurement (ARM) Climate Research Facility in Oklahoma during 2005–2007, we have found that LWP and geometric thickness increase and follow a power-law relationship with cloud optical depth regardless of the presence of drizzle; LWP and geometric thickness in drizzling clouds can be generally 20–40% and at least 10% higher than those in non-drizzling clouds, respectively. In contrast, droplet effective radius shows a negative correlation with optical depth in drizzling clouds and a positive correlation in non-drizzling clouds, where, for large optical depths, it asymptotes to 10 μm. This asymptotic behaviour in non-drizzling clouds is found in both the droplet effective radius and optical depth, making it possible to use simple thresholds of optical depth, droplet size, or a combination of these two variables for drizzle delineation. This paper demonstrates a new way to enhance ground-based cloud observations and drizzle delineations using existing lidar networks.http://www.atmos-chem-phys.net/14/8389/2014/acp-14-8389-2014.pdf
spellingShingle J. C. Chiu
J. A. Holmes
R. J. Hogan
E. J. O'Connor
The interdependence of continental warm cloud properties derived from unexploited solar background signals in ground-based lidar measurements
Atmospheric Chemistry and Physics
title The interdependence of continental warm cloud properties derived from unexploited solar background signals in ground-based lidar measurements
title_full The interdependence of continental warm cloud properties derived from unexploited solar background signals in ground-based lidar measurements
title_fullStr The interdependence of continental warm cloud properties derived from unexploited solar background signals in ground-based lidar measurements
title_full_unstemmed The interdependence of continental warm cloud properties derived from unexploited solar background signals in ground-based lidar measurements
title_short The interdependence of continental warm cloud properties derived from unexploited solar background signals in ground-based lidar measurements
title_sort interdependence of continental warm cloud properties derived from unexploited solar background signals in ground based lidar measurements
url http://www.atmos-chem-phys.net/14/8389/2014/acp-14-8389-2014.pdf
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