1. Exploring a Global Climatology of Tropical Cyclone Eye Sizes ETHAN WRIGHT: UNC ASHEVILLE RESEARCH ADVISOR: DR. CHRISTOPHER HENNON 04/22/2015

2.  Peak Intensity: 190 mph  Lowest Pressure: 870 mb  Small eye size of 8 nm Super Typhoon Tip (1979)

3. Super Typhoon Winnie (1997)  Peak Intensity: 160 mph  Outer ring of convection: 200 nm

4. Goal of this Study  Use a consensus of eye sizes to find the correlation of eye sizes to estimated intensities through analysis of tropical cyclone images classified through Cyclone Center.

5. Cyclone Center  A web site dedicated to the global analysis of archived satellite images of tropical cyclones by “Citizen Scientists”.  Images are analyzed through a set of questions related to the Dvorak Technique.  User responses are recorded and transferred to a number that can be related to a maximum surface wind speed.

6. Power in Numbers  Crowd sourcing has proven to be an effective means of addressing large data sets  HURSAT data contain nearly 3,000 storms, 300,000 images

7.  Jordan 1961 Related MSLP to changes in eye diameter.  Weatherford and Gray 1988 Weak Correlation between MSLP and outer-core strength alone. A more direct relationship between MSLP and outer-core strength is evident when also accounting for eye size.  Kodama and Yamada et al. 2005 Compared IR satellite images to microwave imagery from the Tropical Rainfall Measurement Mission (TRMM) between 1998-2002. Past Research

9.  Disadvantages TC Eye often obscured by cirrus shield Coarse Resolution of 8 KM  Advantages Global Coverage Continuous Data 32 Years of Data Advantages and Disadvantages of Using IR Images

12.  Users Weighted by: Number of Classifications Completed How well user classified “eye storms”

15.  Very low statistical correlation between eye size and intensity through estimated Dvorak classification values.  Average eye size classification for tropical storms: 46 km  Average eye size of tropical cyclones (>64 kts): 34 km  Average “eye storm” wind speed classification: 108 kts Results

16. Possible Future Work  Investigation of TC eye size changes through life cycle stages.  Spatial changes with TC Eye sizes.

17. References Anthes, R. A., 1982: Tropical Cyclones: Their Evolution, Structure and Effects. Science Press, 208 pp. Candis L. Weatherford and William M. Gray, 1988: Typhoon Structure as Revealed by Aircraft Reconnaissance. Part II: Structural Variability. Mon. Wea. Rev., 116, 1044–1056. C. L. Jordan, 1961: MARKED CHANGES IN THE CHARACTERISTICS OF THE EYE OF INTENSE TYPHOONS BETWEEN THE DEEPENING AND FILLING STAGES. J. Meteor., 18, 779–789. Dvorak, V. F., 1975: Tropical cyclone intensity analysis and forecasting from satellite imagery. Mon. Wea. Rev., 103, 420–430. Hennon, C. C., and Coauthors, 2015: Cyclone Center: Can Citizen Scientists Improve Tropical Cyclone Intensity Records?. Bull. Amer. Meteor. Soc. Yasu-Masa Kodama and Takuya Yamada, 2005: Detectability and Configuration of Tropical Cyclone Eyes over the Western North Pacific in TRMM PR and IR Observations. Mon. Wea. Rev., 133, 2213– 2226.

18. Questions/Discussion