1. By: Michelle Tyson Department of Marine and Environmental Systems College of Engineering Florida Institute of Technology FP 2007 Source: University of South Florida

2. OVERVIEW  Research Objective  What is ocean heat content (OHC)?  Why is it important?  Methods  Observed OHC vs. RTOFS OHC forecast  Tropical Storm Barry (2007)  Compare to Hurricane Katrina (2005)  Conclusions  Questions/Comments FP 2007

3. Ocean Heat Content Objective  study the OHC and hurricane heat potential in the Gulf Stream and surrounding areas  Purpose of Study:  Measure the heat content in the upper layer of the ocean between June 2, 2007 and June 8, 2007  Compare observed to the estimated forecast from the Real Time Ocean Forecast System (RTOFS) produced by NOAA/NCEP  Will provide an evaluation of the quality of the RTOFS hurricane heat potential forecast FP 2007

4. What is OHC?  Ocean heat content: The amount of heat stored in the upper layers of the ocean water column.  OHC plays a very important role in the formation and intensity of tropical cyclones which was found during research conducted on hurricanes Opal (1995) and Bret (1999) FP 2007

5. Who Cares?  OHC plays a very important role in the formation and intensity of tropical cyclones  Models are a useful tool in early forecasting of hurricane intensity and path  Quality forecast models is needed due to the importance of early warnings and forecasts of hurricanes Source: Howstuffworks.com FP 2007

6. Methods  Real-time ocean temperatures were observed by using a conductivity- temperature-depth (CTD) profiler  The forecasted ocean temperatures were taken from downloaded archived RTOFS files  The ocean temperatures and salinities were used to calculate OHC through the following equation: FP 2007

7. Observed OHC vs. RTOFS OHC Forecast for June 8, 2007 FP 2007 26º C isotherm Estimated Area under curve: OHC: 1.64 kJ/cm²   These calculations are under-estimated because the depth of the 26° C isotherm was never reached, so therefore the ocean heat content wasn’t fully calculated

8. Observed OHC vs. RTOFS OHC Forecast for 2007 Cruises Note: Observed OHC is indicated by the blue bars, the RTOFS 1-day forecast is indicated by the red bar, and the RTOFS 5-day forecast forecast is indicated by the red bar, and the RTOFS 5-day forecast is indicated by the yellow bar Cooler Shelf Waters Gulf Stream and Surrounding areas FP 2007

9. Tropical Storm Barry  Formed in the Gulf of Mexico on June 1, 2007  Winds ranging above 39 m.p.h.  Moving NE toward Tampa, FL (indicated by )  Landed on Florida’s western coast on June 2, 2007 as a minimal tropical storm with a max wind speed of 60 m.p.h.  Barely strengthened due to high wind sheer and low to high wind sheer and low values of OHC through the values of OHC through the Gulf of Mexico Gulf of Mexico FP 2007

10. Winds increased from 65kts to 100kts (cat 3) August 27, 2005 (1200 UTC) Hurricane Katrina  Formed in the SE of the Bahamas on Aug. 18  Moved across southern FL  6 th strongest ever recorded  3 rd strongest to make landfall in the US  Over 1800 lives taken 24.5º N 84.5º W

11. Increased to a cat 5 with peak winds of 150 kts August 28, 2005 (1800 UTC) 26.5º N 89.5º W

12.  A low ocean heat content was calculated for observed and RTOFS  A small difference of OHC in noted  Warmer waters of the Gulf Stream vs. cooler shelf waters  RTOFS 1-day model forecasted OHC values higher than the observed  The difference was very minimal~ 0.448 kJ/cm² Conclusions FP 2007

13. Conclusions Cont’d  RTOFS 5-day model forecasted OHC values lower than the observed on June 3 rd,4 th,6 th, 7 th  RTOFS forecasted values of 0 kJ/cm² due to temperatures lower than 26º C  RTOFS 5-day model forecasted OHC values higher than the observed on June 5 th and 8 th  Average difference was.523 kJ/cm²  OHC shown to change the strength of tropical storms  High OHC strengthened Katrina (2005)  Low OHC stalled strengthening of Barry (2007) FP 2007

14. QUESTIONS??