P1.46
Retrievals of Mixed-Phase Cloud Properties During NPOESS
S. C. Ou, Univ. of California, Los Angeles, CA; and X. Wang, D. Hagan, A. W. Dybdahl, M. Mussetto, L. D. Carey, K. N. Liou, J. Niu, J. A. Kankiewicz, S. Kidder, and T. H. Vonder Haar
An ability to detect mixed phase conditions and to retrieve their optical properties is important for numerical weather prediction and civil and military aircraft operations. In the current National Polar-orbiting Operational Environmental Satellite System (NPOESS) Visible Infrared Imaging Radiometer Suite (VIIRS) cloud algorithm chain, cloud phase is determined by the NPOESS/VIIRS cloud mask, which has been designed specifically to differentiate between a mixed phase cloud and a condition of thin ice cloud overlapping water cloud. Subsequently, separate optical property retrieval algorithms are applied to these dual-phase pixels, which are treated either as water cloud or as ice cloud.
This poster describes a new approach developed for the NPOESS to retrieve pixel-level, mixed-phase cloud optical thickness (COT) and effective particle size (EPS) from radiances observed in the 0.67, 1.6, 2.13 and 3.7μm bands. The COT and EPS are retrieved from a numerical search method using look-up tables of reflectances for the four bands based on radiative transfer simulations. The capability of this new approach has been demonstrated using MODIS data as a proxy to VIIRS. A proxy scene, October 14, 2001 over North Platte, Nebraska during the ninth Cloud Layer Experiment (CLEX-9) has been analyzed. For this date, airborne in situ observations by the University of Wyoming King Air Cloud Research Aircraft were collected, collocated and coincident with Terra/MODIS overpass. Layers of mixed-phase clouds were detected through these in-situ measurements. Results of comparison between retrieved and observed cloud optical properties will be presented in the conference, along with discussions on the potential application of this new approach.
Poster Session 1, 4th NPOESS Symposium Poster Session
Tuesday, 22 January 2008, 9:45 AM-11:00 AM, Exhibit Hall B
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