Arctic Mixed-Phase Cloud Properties from AERI Lidar Observations: Algorithm and Results from SHEBA

Journal Article · Fri Apr 01 04:00:00 EST 2005 · Journal of Applied Meteorology, 44(4):427-444

DOI:https://doi.org/10.1175/JAM2208.1· OSTI ID:15020524

Turner, David D

A new approach to retrieve microphysical properties from mixed-phase Arctic clouds is presented. This mixed-phase cloud property retrieval algorithm (MIXCRA) retrieves cloud optical depth, ice fraction, and the effective radius of the water and ice particles from ground-based, high-resolution infrared radiance and lidar cloud boundary observations. The theoretical basis for this technique is that the absorption coefficient of ice is greater than that of liquid water from 10 to 13 μm, whereas liquid water is more absorbing than ice from 16 to 25 μm. MIXCRA retrievals are only valid for optically thin (τvisible < 6) single-layer clouds when the precipitable water vapor is less than 1 cm. MIXCRA was applied to the Atmospheric Emitted Radiance Interferometer (AERI) data that were collected during the Surface Heat Budget of the Arctic Ocean (SHEBA) experiment from November 1997 to May 1998, where 63% of all of the cloudy scenes above the SHEBA site met this specification. The retrieval determined that approximately 48% of these clouds were mixed phase and that a significant number of clouds (during all 7 months) contained liquid water, even for cloud temperatures as low as 240 K. The retrieved distributions of effective radii for water and ice particles in single-phase clouds are shown to be different than the effective radii in mixed-phase clouds.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 15020524
• Report Number(s): PNNL-SA-39408
• Journal Information: Journal of Applied Meteorology, 44(4):427-444, Journal Name: Journal of Applied Meteorology, 44(4):427-444 Journal Issue: 4 Vol. 44
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ABSORPTION
ALGORITHMS
ARCTIC OCEAN
CLOUDS
ICE
INTERFEROMETERS
OPTICAL PROPERTIES
OPTICAL RADAR
WATER VAPOR
doppler radar
emitted radiance interferometer
independent spheres
infrared observations
nonspherical ice particle
optical-constants
radiative properties
resolving simulations
stratus cloud
surface heat-budget