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Shark Team

Shark Team. Jenny Hodbod Jason Owens Aaron Sidder. The Question. Is there a correlation between hurricane strength (intensity) and frequency vs. time?. http://www.katrina-hurricane.biz/images/katrina-hurricane-pic3.jpg. Methods. Analyze the total number of storms per decade

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Shark Team

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  1. Shark Team Jenny Hodbod Jason Owens Aaron Sidder

  2. The Question • Is there a correlation between hurricane strength (intensity) and frequency vs. time? http://www.katrina-hurricane.biz/images/katrina-hurricane-pic3.jpg

  3. Methods • Analyze the total number of storms per decade • Analyze the average maximum wind speed per year by decade and the maximum wind speed per decade • Analyze the number of Category 4 & 5 hurricanes per decade

  4. Chi Squared Tests • Fo= observed data hurricane data smoothed into decadal averages • Fe= expected data average for the whole data set • (fo-fe)^2/fe • Sum of the chi squared values • Compare to the critical chi squared values

  5. Biases and Data Limitations • Advances in technology from 1850 (pre-Civil War) to 2006 • Limited time frame, no knowledge of historical storm data beyond 1850 • 2005 was a crazy year that skewed the data

  6. Expected and Observed Hurricane Frequencies

  7. Chi Squared test: Frequency • Null Hypothesis= the total number of events is not increasing per decade • Used the average for the entire data set: fe= 85 events per decade • 16 df: critical chi squared value at 5% is 26.30 • Chi squared total is 53.02 • Reject null hypothesis

  8. Chi Squared: Frequency cont.

  9. Event Category as a % of Total Biggest increases are in TS, 4 &5 Tropical storms increase (y=1.9985x +17.2) Category 1 events show a slight increase (y= 0.3029 +16.55) Category 2 events show a decrease (y = -0.775x +20.65) Category 3 events show a slight increase (y= 0.1191x + 9.425) Category 4 events show an increase (y=0.6162x + 0.575) Category 5 events show an increase (y= 0.3456x-1.125)

  10. Category 4&5 increase TS and Category 1 are increasing 2&3 are decreasing 4&5 are increasing

  11. Frequency of Category 5 Events

  12. Category 4&5 increase • Null hypothesis= category 4 & 5 hurricanes are not increasing in frequency • Fe= average number of 4&5 per decade= 8 • Total chi squared value= 56.62 • More than the critical chi squared value (26.30) • Reject the null hypothesis

  13. Maximum Wind Speeds

  14. Chi Squared: Wind Speed • Average the maximum wind speed per year by decade • Average of these 16 speeds =115 mph (fe) • Null hypothesis= no increase in wind speed over time • Sum of the chi squared values= 20.02 • Below the critical chi squared value for 16df (26.30), therefore accept the null hypothesis

  15. Chi Squared: Wind Speed cont • Using the maximum wind speed per decade • Average = 142.5 = fe • Sum of chi squared values= 29.47 • Reject the null hypothesis at the 5% probability level

  16. Number of Storms Through Time

  17. Who is this?!

  18. Trying to Summon Nikola Tesla?

  19. Number of Storms Through Time

  20. Troughs and Spikes can clearly be seen

  21. Cycles drive our dynamic Planet

  22. Conclusion Increase in frequency through time? YES Increase in severity through time? YES Manifestation of anthropogenic Climate change? ???

  23. Manatees and Hurricanes Source: WEST INDIAN MANATEE (Trichechus manatus latirostris): FLORIDA STOCK U.S. Fish and Wildlife Service, Jacksonville, Florida; September 2000

  24. Average # of storms by decade as compared to Sea Surface Temp.

  25. Average # of storms by decade as compared to Sea Surface Temp. • Two-way chi squared test: • SST anomaly and Average # of storms/yr by decade • Null Hypothesis= no relationship between the two • Total chi squared value = 29.99 • Reject the null hypothesis

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