Atmospheric Radiation Measurement Climate Research Facility US Department of Energy
 

CLOUDEXT

 

Parameterization of Extinction Coefficient in Ice and Mixed-Phase Arctic Clouds During ISDAC

1 October 2010 - 31 December 2011

Lead Scientist: Alexei Korolev

Observatory: AAF, NSA

A primary goal of the Atmospheric Radiation Measurement (ARM) Program is to improve the representation of clouds and related processes in Global Climate Models (GCM). Significant effort has been undertaken to improve the parameterization of extinction coefficient of ice and mixed-phase clouds based on measurements collected with airborne cloud particle size spectrometers. However, these techniques have a large uncertainty related to the accuracy of size-to-area conversion used in the calculation of extinction coefficient and more general issues related to the accuracy of particle sizing, measurements of particle concentration, and an unresolved problem with ice particle shattering on instrument inlets. Recently, a major field campaign coordinated by DOE, called the Indirect-Semi-Direct Aerosol Campaign (ISDAC), was conducted in Barrow, Alaska. During ISDAC a newly developed airborne cloud Extinction Probe was installed onboard the NRC Convair-580 research aircraft. This instrument provides measurements of cloud extinction coefficient from first principles based on the Beer-Bouguer law. An advantage of this instrument is the large distance between the transmitter/receiver and the retro-reflector. This makes its measurements practically insensitive to the shattering of ice particles. These new measurements may be used for validation of existing parameterizations of extinction coefficient and for helping to solve a long-standing problem related to the existence of small particles in ice clouds. We performed a set of laboratory and theoretical calibrations of the Extinction Probe. The calibrations were used to establish the correction function for forward scattering which becomes significant when large cloud particles are present. This correction was applied to extinction coefficients reported in ISDAC data. The corrected data was used for parameterization of extinction coefficient in Arctic ice and mixed-phase clouds and for drawing conclusions about the existence of small ice particle based on the closure of measured extinction coefficient and extinction coefficient derived from measurements of ice particle sizes.

Related Publications

2014

Schmid B, JM Tomlinson, JM Hubbe, JM Comstock, F Mei, D Chand, MS Pekour, CD Kluzek, E Andrews, SC Biraud, and GM McFarquhar. 2014. "The DOE ARM Aerial Facility." Bulletin of the American Meteorological Society, 95(5), 10.1175/bams-d-13-00040.1.


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NSA Data Sources

Name Full Name Browse Data
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AOS Aerosol Observing System Browse Data
ARMBE ARM Best Estimate Data Products Browse Data
ARSCL Active Remotely-Sensed Cloud Locations Browse Data
CCN Cloud Condensation Nuclei Particle Counter Browse Data
CEIL Ceilometer Browse Data
CLAP Continuous Light Absorption Photometer Browse Data
CPC Condensation Particle Counter Browse Data
CSPHOT Cimel Sunphotometer Browse Data
DL Doppler Lidar Browse Data
DLPROF Doppler Lidar Profiles Browse Data
ECMWFDIAG European Centre for Medium Range Weather Forecasts Diagnostic Analyses Browse Data
ECOR Eddy Correlation Flux Measurement System Browse Data
GNDRAD Ground Radiometers on Stand for Upwelling Radiation Browse Data
GVRP G-band (183 GHz) Vapor Radiometer Profiler Browse Data
GVRPWV G-Band Vapor Radiometer Precipitable Water Vapor Browse Data
HSRL High Spectral Resolution Lidar Browse Data
INTERPSONDE Interpolated Sonde Browse Data
IRT Infrared Thermometer Browse Data
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KAZR Ka ARM Zenith Radar Browse Data
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KAZRCOR KAZR Corrected Data Browse Data
MERGESONDE Merged Sounding Browse Data
MET Surface Meteorological Instrumentation Browse Data
MFR Multifilter Radiometer Browse Data
MFRSR Multifilter Rotating Shadowband Radiometer Browse Data
MFRSRCLDOD Cloud Optical Properties from MFRSR Using Min Algorithm Browse Data
MICROBASE Continuous Baseline Microphysical Retrieval Browse Data
MMCR Millimeter Wavelength Cloud Radar Browse Data
MMCRMODE MMCR mode moments, derived by ARSCL process Browse Data
MOLTS Model Output Location Time Series Browse Data
MPL Micropulse Lidar Browse Data
MPLAVG MPL: data averaged to fixed 30 second interval, e.g. for polarized data Browse Data
MPLCMASK Cloud mask from Micropulse Lidar Browse Data
MWR Microwave Radiometer Browse Data
MWRHF Microwave Radiometer - High Frequency Browse Data
MWRP Microwave Radiometer Profiler Browse Data
MWRRET MWR Retrievals Browse Data
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NIMFR Normal Incidence Multifilter Radiometer Browse Data
NOAACRN NOAA Climate Reference Network Browse Data
NOAARAD NOAA/ESRL/GMD Radiometers Browse Data
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ORG Optical Rain Gauge Browse Data
PBLHT Planetary Boundary Layer Height Browse Data
PSAP Particle Soot Absorption Photometer Browse Data
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SEBS Surface Energy Balance System Browse Data
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SONDEADJUST Sonde Adjust Browse Data
SURFSPECALB Surface Spectral Albedo Browse Data
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TPS Total Precipitation Sensor Browse Data
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