Varying Structure and Intensity Change Characteristics of Four Western North Pacific Tropical Cyclones.
COLORADO STATE UNIV FORT COLLINS DEPT OF ATMOSPHERIC SCIENCE
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Observational case studies of four tropical cyclones Ellis, Hope, Judy, and Roger from birth to decay are made using a variety of data sources from the First GARP Global Experiment FGGE year 1979. Each of these cyclones had uniquely different characteristics. Two became supertyphoons, one only a weak typhoon, and one only a tropical storm with a strong outer circulation. Two recurved, and two did not recurve. Information was derived from a combination of European Centre for Medium Range Weather Forecasts ECMWF large scale objective analyses, Joint Typhoon Warning Center JTWC Guam manual analyses, National Climatic Center NCC analyses published by the National Oceanic and Atmospheric Administration NOAA, United States Air Force USAF aircraft reconnaissance data, and U.S. Defense Meteorological Satellite Program DMSP military satellite imagery. The combination of these rich data sources allowed a quantitative description of both large and small scale features. Emphasis is placed on cyclone structure and intensity change. Quantitative assessments of the varying relationships between inner and outer radii wind parameters are made. Preliminary results show the importance of the large scale radius greater than seven degrees environment in determining cyclone genesis and the importance of upper tropospheric outflow patterns in determining cyclone inner-core intensity change.