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
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
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
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.9.7.14. 4
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
HURDAT Pressure Counts 19-5 Availability of Pressure Observations by Decade 4 35 3 25 Frequency 15 5 19 19 19 193 194 195 196 197 198 199 Decade Pressures NoPressures 6
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 19 19 19 193 194 195 196 197 198 199 No Pressures Pressures 8
15 N Mile Gulf Coast C p (19-5) Camille Katrina Opal Allen 9
9 N Mile Gulf Coast C p (19-5) Camille Katrina
Along Coast C p Return Periods 11 11
C p Return Periods for Zone B: 9 N Mile Offshore Extent 5 & N Mile Lateral Extensions 95 94 Zone B (Central Gulf): 9 N Mile CPI with 5 N Mile overlap Zone B: 1941-5 Zone B: 1965-5 95 94 Zone B (Central Gulf): 9 N Mile CPI with N Mile overlap Zone B: 1941-5 Zone B: 1965-5 Central Pressure Index (mb) 93 9 9 9 89 -year = 9 mb -year = 94.8 mb Central Pressure Index (mb) 93 9 9 9 89 -year = 916.2 mb -year = 9 mb 88 88 87 3 4 5 87 3 4 5
CPI Return Periods for Zone B: 15 N Mile Offshore Extent 5 & N Mile Lateral Extensions 94 93 Zone B (Central Gulf): 15 N Mile CPI with 5 N Mile overlap Zone B: 1941-5 Zone B: 1965-5 94 93 Zone B (Central Gulf): 15 N Mile CPI with N Mile overlap Zone B: 1941-5 Zone B: 1965-5 Central Pressure Index (mb) 9 9 9 89 88 -year = 913.7 mb -year = 895.6 mb Central Pressure Index (mb) 9 9 9 89 88 -year = 9.4 mb -year = 892.3 mb 87 87 86 3 4 5 86 3 4 5
C p Return Periods (15 N Mi offshore) Zone C: Texas & Western Gulf Coast 96 95 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) 94 93 9 9 939.6 mb 934.1 mb 924.7 mb 918.7 mb 9 14 89 3 4 5
Western Gulf Coast (Zone C) Return Periods and 9% Confidence Intervals Satellite Era 4-year Period (1965-5) 96 94 Central Pressure Index (mb) 9 9 88 3 4 5 Return Period (Years) 15
Texas: C p vs. ΔP 12 Hour Change in Central Pressure Deficit Before Landfall 4 3 - - -3-4 Texas y =.374x - 358.7 R² =.544 9 9 94 96 98 12 Hour Change in Central Pressure Deficit Before Landfall 4 3 - - -3-4 Texas y =.23x - 218.1 R² =.4 9 9 94 96 98 Pre-Landfall Pressure (mbar) Landfall Pressure (mbar) Data coverage: 1964-8 16
Florida Panhandle: C p vs. ΔP 4 NW Florida 4 NW Florida 12 Hour Change in Central Pressure Deficit Before Landfall 3 - - -3-4 y =.319x - 3.2 R² =.65 9 9 94 96 98 12 Hour Change in Central Pressure Deficit Before Landfall 3 - - -3-4 y =.285x - 277.1 R² =.254 9 9 94 96 98 Pre-Landfall Pressure (mbar) Landfall Pressure (mbar) Data coverage: 1964-8 17
Louisiana: C p vs. ΔP 12 Hour Change in Central Pressure Deficit Before Landfall 4 3 - - -3-4 Louisiana y =.273x - 264.1 R² =.565 9 9 94 96 98 Pre-Landfall Pressure (mbar) 12 Hour Change in Central Pressure Deficit Before Landfall 4 3 - - -3-4 Louisiana y =.241x - 233.7 R² =.258 9 9 94 96 98 Landfall Pressure (mbar) Data coverage: 1964-8 18
LA, MS & AL: C p vs. ΔP 12 Hour Change in Central Pressure Deficit Before Landfall 4 3 - - -3-4 Louisiana/Mississippi/Alabama y =.212x - 4.8 R² =.445 9 9 94 96 98 Pre-Landfall Pressure (mbar) 12 Hour Change in Central Pressure Deficit Before Landfall 4 3 - - -3-4 Louisiana/Mississippi/Alabama y =.164x - 159.2 R² =.18 9 9 94 96 98 Landfall Pressure (mbar) Data coverage: 1964-8 19
All Gulf Coast Hurricanes 4 4 12 Hour Change in Central Pressure Deficit (mbar) Before Landfall 3 - - -3-4 y = 3.7E-1x - 2.95E+2 R² = 5.4E-1 9 95 5 Pre-Landfall Pressure (mbar) with Camille 12 Hour Change in Central Pressure Deficit (mbar) Before Landfall 3 - - -3-4 Data coverage: 1959-8 y = 3.3E-1x - 2.91E+2 R² = 5.E-1 9 95 5 Pre-Landfall Pressure (mbar) without Camille
Gulf Coast 198-8 Data Only 12 Hour Change in Central Pressure Deficit Before Landfall 4 3 - - -3 y = 3.32E-1x - 3.21E+2 R² = 7.91E-1-4 9 9 94 96 98 Pre-Landfall Pressure (mbar) 21
TC Intensity Changes Along Gulf Coast From Rappaport et al. (9) Wea. Forecast.
48-hr ΔC p Landfalling Hurricanes From Rappaport et al. (9) Wea. Forecast. (a) p H, 12h (12 h) (mb) -3 - - (c) p H, 36h (mb) 3-3 - - 3 98 86B 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 = 336.77 = 336.8 -.34952x -.3495p R=.75264 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 94 94 4I1 p y = 678.34 = 678.3 H, 36h -.71598x -.716p R= H.78682 r =.79 p H (mb) 8A 93 9 95O 9 5K 9 5R 9 (b) p H, 24h (mb) -3 - - (d) p H, 48h (mb) 3 4-4 -3 - - 3 4 83A 95A G 98 5W 98G 85E 96 95O 5D 8G 79F 8I 99B 2L 92A 85K 4I1 p y = 377.32 = 377.3 H, 24h -.39449x -.3945p R= H.61766 r =.62 99B 85E 95O 98G 85K Data coverage: 1979-8 79F 98 8I 96 p H (mb) 5K 8A 94 94 4I1 y p= 77.86 = 77.9 H, 48h -.74872x -.7487p R= H.87132 r =.87 p H (mb) 9 5R 9 5R 9 5K 8A 9 88
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
http://www.ncdc.noaa.gov/oa/ibtracs 25
Thank you! 26