HR: 1340h
AN: A23C-0957    [Abstracts]
TI: Derivation of Cloud Heating Rate Profiles using observations of Mixed-Phase Arctic Clouds: Impacts of Solar Zenith Angle
AU: * Zhang, G
EM: gzhang2@atmos.uiuc.edu
AF: Department of Atmospheric Sciences, University of Illinois, Department of Atmospheric Sciences 105 S Gregory Street, Urbana, IL 61801 United States
AU: McFarquhar, G
EM: mcfarq@atmos.uiuc.edu
AF: Department of Atmospheric Sciences, University of Illinois, Department of Atmospheric Sciences 105 S Gregory Street, Urbana, IL 61801 United States
AU: Poellot, M
A23C-0957 AF: Department of Atmospheric Sciences, University of North Dakota, Department of Atmospheric Sciences PO Box 9006 , Grand Forks, ND 58202 United States
AU: Verlinde, J
A23C-0957 AF: Department of Meteorology, Pennsylvania State University, Department of Meteorology, 503 Walker Bldg. , University Park, PA 16802 United States
AU: Heymsfield, A
A23C-0957 AF: National Center for Atmospheric Research, National Center for Atmospheric Research PO Box 3000, Boulder, CO 80307 United States
AU: Kok, G
A23C-0957 AF: Droplet Measurement Technologies, 5710 Flatiron Parkway Suite B , Boulder, CO 80301 United States
AB: Arctic stratus clouds play an important role in the energy balance of the Arctic region. Previous studies have suggested that Arctic stratus persist due to a balance among cloud top radiation cooling, latent heating, ice crystal fall out and large scale forcing. In this study, radiative heating profiles through Arctic stratus are computed using cloud, surface and thermodynamic observations obtained during the Mixed-Phase Arctic Cloud Experiment (M-PACE) as input to the radiative transfer model STREAMER. In particular, microphysical and macrophycial cloud properties such as phase, water content, effective particle size, particle shape, cloud height and cloud thickness were derived using data collected by in-situ sensors on the University of North Dakota (UND) Citation and ground-based remote sensors at Barrow and Oliktok Point. Temperature profiles were derived from radiosonde launches and a fresh snow surface was assumed. One series of sensitivity studies explored the dependence of the heating profile on the solar zenith angle. For smaller solar zenith angles, more incoming solar radiation is received at cloud top acting to counterbalance infrared cooling. As solar zenith angle in the Arctic is large compared to low latitudes, a large solar zenith angle may contribute to the longevity of these clouds.
DE: 0320 Cloud physics and chemistry
DE: 0321 Cloud/radiation interaction
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005