89th American Meteorological Society Annual Meeting

Tuesday, 13 January 2009
Retrieving Upper and Lower Cloud Layer Properties Using the GOES-12 Imagery Data: Addressing Problems in Satellite Retrievals of Cloud Layers
Hall 5 (Phoenix Convention Center)
Fu-Lung Chang, SSAI, Hampton, VA; and P. Minnis, B. Lin, R. Palikonda, and D. A. Spangenberg
Passive meteorological satellites have long served as the main workhorse for observing cloud parameters, but operational satellite cloud retrieval algorithms have typically assumed the simple model of a single-layer cloud in retrieving the cloud top location and cloud bulk properties. The imager used on the old Geostationary Operational Environmental Satellite-I series (GOES-I) imagers (e.g., GOES-8, GOES-10) was modified, replacing the 12.0-Ám channel with the 13.3-Ám channel, and placed on the GOES-M imagers (GOES-12/13). The 13.3-Ám channel, also on the future GOES-R Advanced Baseline Imager, measures spectra attenuated by CO2 absorption permitting the application of CO2 absorption technique to improve the cloud-layer height retrieval.

In this study, an iterative retrieval of the upper and lower cloud layer properties using the GOES-12 imagery data is presented for future operational inferences of single-layered and multilayer cloud properties. The new iterative retrieval invokes two techniques: an iterative CO2-IR absorbing technique and an iterative IR-Visible cloud optical depth technique. The former is a modified CO2 absorption method that determines the upper and lower cloud layer locations using the 10.8 and 13.3-Ám data, while the latter determines the upper and lower cloud layer optical depths using two-layered cloud radiative transfer modeling. Results are presented from retrieval sensitivity tests in terms of instrument noise and model uncertainties. The retrievals are validated by comparing with ground- and satellite-based active remote sensing data. Finally, results obtained from near real-time image analyses using the new iterative retrieval are demonstrated for the GOES-12 and Meteosat Second Generation (MSG) satellite imagers.

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