Investigation of Composite Cloud Fields as Applied to Tropical Storm Forecasting.
AIR FORCE GEOPHYSICS LAB HANSCOM AFB MASS
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This report reviews the work reported earlier in AFGL-TR-76-0170, Cloud Distributions as Indicators of Tropical Storm Displacement, by the same author, on the application of composite cloud imagery to the forecasting of tropical storm motion. Several additional techniques that were tested briefly for application to typhoon specification and forecasting are discussed and evaluated. Animations of 12-hour infrared images did not suggest anything useful within the limited time available for analysis. The technique, however, should be comprehensively tested with data of better time and spatial resolution. Infrared composites appeared to be less useful than visual composites. The increased detectability of thin cirrus clouds in the infrared masked the significant cloud features. An attempt to duplicate Dvoraks relationships between peak wind speed and the central and banding features of typhoons by compositing storms of similar intensity failed. The fine details Dvorak could distinguish in individual storms were destroyed by the compositing process. Objective analysis of satellite imagery of typhoons is seriously handicapped by the limited archive of digital data. Author