A Climatology of Landfalling Hurricane Central Pressures Along the Gulf of Mexico Coast

Transcription

1 A Climatology of Landfalling Hurricane Central Pressures Along the Gulf of Mexico Coast David H. Levinson NOAA National Climatic Data Center Asheville, NC Peter J. Vickery Applied Research Associates, Inc. Raleigh, NC Donald T. Resio USACE /ERDC Coastal & Hydraulics Laboratory Vicksburg, MS October 19, 9 1

2 Outline & Motivation for Study Analyze the climatological characteristics of landfalling Gulf of Mexico hurricanes specifically for wave and surge modeling: -m wind (U ), Wind stress (τ), drag coefficient (C D ), central pressure (C p ), peripheral pressure (P o ), and central pressure deficit (ΔP) Central Pressure (C p ) - directly observed measure of TC max intensity Discuss the historical observations of C p related to Gulf Coast hurricanes Return periods and along-shore variability of C p over different sections of Gulf Coast Analyze the changes in C p prior to, and during, landfall 12-hr change in Gulf hurricane ΔP and C p 2

3 Methodology Examine 6-hr C p observations from HURDAT Assess best period of record for analysis Correlate Pre-Landfall & Landfall C p with ΔP Analyze by sub-region along Gulf Coast Assess along-shore variability: C p return periods Correlate pre-landfall and landfall ΔP for different sections of Gulf Coast 3

4 Conclusions Significant along-shore variability in C p return period Lowest in the central Gulf Coast region (LA & MS) Period of record strongly affects results Broad confidence limits! Correlation of 12-hr change in Pressure Differential (ΔP) and C p Pre-landfall C p has higher correlation than landfall C p Highest correlations found for LA and FL Panhandle Best correlations using data since 198 Levinson, D.H., P.J. Vickery and D.T. Resio, 9: A review of the climatological characteristics of landfalling Gulf hurricanes for wind, wave, and surge hazard. Ocean Engineering, doi:.16/j.oceaneng

5 HURDAT Since 1851 All Observations Including Missing Pressures: 37,854 points Observations w/ Pressures: 12,95 points 5 11th Int l Workshop on Wave Hind-casting and Forecasting & 2nd Coastal Hazards Symposium

6 HURDAT Pressure Counts 19-5 Availability of Pressure Observations by Decade Frequency Decade Pressures NoPressures 6

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8 Availability of Pressure Observations by Decade and Zone 1 8 Frequency 6 4 A B C A B C A B C A B C A B C A B C A B C A B C A B C A B C A B C No Pressures Pressures 8

9 15 N Mile Gulf Coast C p (19-5) Camille Katrina Opal Allen 9

10 9 N Mile Gulf Coast C p (19-5) Camille Katrina

11 Along Coast C p Return Periods 11 11

12 C p Return Periods for Zone B: 9 N Mile Offshore Extent 5 & N Mile Lateral Extensions Zone B (Central Gulf): 9 N Mile CPI with 5 N Mile overlap Zone B: Zone B: Zone B (Central Gulf): 9 N Mile CPI with N Mile overlap Zone B: Zone B: Central Pressure Index (mb) year = 9 mb -year = 94.8 mb Central Pressure Index (mb) year = mb -year = 9 mb

13 CPI Return Periods for Zone B: 15 N Mile Offshore Extent 5 & N Mile Lateral Extensions Zone B (Central Gulf): 15 N Mile CPI with 5 N Mile overlap Zone B: Zone B: Zone B (Central Gulf): 15 N Mile CPI with N Mile overlap Zone B: Zone B: Central Pressure Index (mb) year = mb -year = mb Central Pressure Index (mb) year = 9.4 mb -year = mb

14 C p Return Periods (15 N Mi offshore) Zone C: Texas & Western Gulf Coast CPI Return Periods for Zone C (Texas & Western Gulf Coast) 6-yr Record (19-5) 65-yr Record (1941-5) 41-yr Record (1965-5) 3-yr Record (1976-5) Central Pressure Index (mb) mb mb mb mb

15 Western Gulf Coast (Zone C) Return Periods and 9% Confidence Intervals Satellite Era 4-year Period (1965-5) Central Pressure Index (mb) Return Period (Years) 15

16 Texas: C p vs. ΔP 12 Hour Change in Central Pressure Deficit Before Landfall Texas y =.374x R² = Hour Change in Central Pressure Deficit Before Landfall Texas y =.23x R² = Pre-Landfall Pressure (mbar) Landfall Pressure (mbar) Data coverage:

17 Florida Panhandle: C p vs. ΔP 4 NW Florida 4 NW Florida 12 Hour Change in Central Pressure Deficit Before Landfall y =.319x R² = Hour Change in Central Pressure Deficit Before Landfall y =.285x R² = Pre-Landfall Pressure (mbar) Landfall Pressure (mbar) Data coverage:

18 Louisiana: C p vs. ΔP 12 Hour Change in Central Pressure Deficit Before Landfall Louisiana y =.273x R² = Pre-Landfall Pressure (mbar) 12 Hour Change in Central Pressure Deficit Before Landfall Louisiana y =.241x R² = Landfall Pressure (mbar) Data coverage:

19 LA, MS & AL: C p vs. ΔP 12 Hour Change in Central Pressure Deficit Before Landfall Louisiana/Mississippi/Alabama y =.212x R² = Pre-Landfall Pressure (mbar) 12 Hour Change in Central Pressure Deficit Before Landfall Louisiana/Mississippi/Alabama y =.164x R² = Landfall Pressure (mbar) Data coverage:

20 All Gulf Coast Hurricanes Hour Change in Central Pressure Deficit (mbar) Before Landfall y = 3.7E-1x E+2 R² = 5.4E Pre-Landfall Pressure (mbar) with Camille 12 Hour Change in Central Pressure Deficit (mbar) Before Landfall Data coverage: y = 3.3E-1x E+2 R² = 5.E Pre-Landfall Pressure (mbar) without Camille

21 Gulf Coast Data Only 12 Hour Change in Central Pressure Deficit Before Landfall y = 3.32E-1x E+2 R² = 7.91E Pre-Landfall Pressure (mbar) 21

22 TC Intensity Changes Along Gulf Coast From Rappaport et al. (9) Wea. Forecast.

23 48-hr ΔC p Landfalling Hurricanes From Rappaport et al. (9) Wea. Forecast. (a) p H, 12h (12 h) (mb) (c) p H, 36h (mb) B 85D 79F 99B 5D 98G 95E 98 8D 83A 85J1 89C 79B 99I 85K 85J2 4C 8I 8G 79F 96 5W 98G 85E p y = = x p R= r = H, 12h H 97 85E 2L 95O 85K 8G 96 p H (mb) + 67B 95 8I 92A 5K 5R 99B 4I1 5D 92A 2L 8A I1 p y = = H, 36h x -.716p R= H r =.79 p H (mb) 8A O 9 5K 9 5R 9 (b) p H, 24h (mb) (d) p H, 48h (mb) A 95A G 98 5W 98G 85E 96 95O 5D 8G 79F 8I 99B 2L 92A 85K 4I1 p y = = H, 24h x p R= H r =.62 99B 85E 95O 98G 85K Data coverage: F 98 8I 96 p H (mb) 5K 8A I1 y p= = 77.9 H, 48h x p R= H r =.87 p H (mb) 9 5R 9 5R 9 5K 8A 9 88

24 Concluding Remarks Future Work EOF analysis Atlantic basin MSLP with Ocean Weather, Inc. and USACE/CHL Correlate EOFs of MSLP with hurricane activity, tropical Atlantic SST and wind shear (85- hpa) International Best Track Archive for Climate Stewardship (IBTrACS) Comprehensive Global Best Track Dataset Version 2 released in July 9 Includes updated files through the end of 8 24

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26 Thank you! 26