An Evaluation of Northern Hemisphere Merged Cloud Analyses from the United States Air Force Cloud Depiction Forecasting System II
NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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Data from the CloudSat cloud profiling radar was used to verify the performance, or operational health, of the United States Air Force s World Wide Merged Cloud Analysis WWMCA system to detect clouds. WWMCA performance for 2010 over the Northern Hemisphere was analyzed by 1 cloud event category Cloudy, Partly Cloudy, Clear 2 geographic region Northern Hemisphere, 0N 50N, 0N 23.5N, 23.5N 35N, 35N-50N, 50N 90N, South China Sea, and Southwest Asia, 3 month and 4 age of input data used by WWMCA. Overall and cloud category performance were evaluated using 11 performance metrics. Overall, WWMCA properly identified cloud categories 65 of the time, with a detection range of 40 70 depending on the region. WWMCA performed best worst at low high latitudes. Decreases in WWMCA accuracy were noted when using input data older than 45 minutes. We confirmed that newer older data performed best worst, with an improvement of nearly 20 when using all data available rather than data older than 3 hours. Annual hemispheric average Heidke skill scores were 0.52 for Cloudy, 0.47 for Clear, and 0.09 for Partly Cloudy conditions. Maximum minimum HSS values for all three cloud categories occurred at low high latitudes.
- Atmospheric Physics