Database Database Re-analysis Project – Results Re-analysis Project – Results for 1851 to 1910 and 1992’s for 1851 to 1910 and 1992’s Hurricane Andrew Hurricane Andrew Chris Landsea NOAA/Hurricane Research Division Miami, Florida, USA CSU/CIRA April 2 nd , 2004 Co-Authors: Craig Anderson, Noel Charles, Gil Clark, Peter Dodge, Jason Dunion, Jose Fernandez-Partagas, James Franklin, Paul Hungerford, Charlie Neumann, Mark Zimmer, and the NHC Best Track Change Committee Acknowledgments: Sim Aberson, Auguste Boissonnade, Emery Boose, Mike Chenoweth, Hugh Cobb, Jose Colon, Neal Dorst, Paul Hebert, Brian Jones, Lorne Ketch, Cary Mock, Ramon Perez Suarez, David Roth, Al Sandrik, and David Vallee.
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Chris Landsea NOAA/Hurricane Research Division Miami, Florida, USA CSU/CIRA April 2 nd , 2004
The Atlantic Hurricane Database Re-analysis Project – Results for 1851 to 1910 and 1992’s Hurricane Andrew. Chris Landsea NOAA/Hurricane Research Division Miami, Florida, USA CSU/CIRA April 2 nd , 2004. - PowerPoint PPT Presentation
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The Atlantic Hurricane Database The Atlantic Hurricane Database Re-analysis Project – Results for 1851 to Re-analysis Project – Results for 1851 to
1910 and 1992’s Hurricane Andrew1910 and 1992’s Hurricane AndrewChris Landsea
NOAA/Hurricane Research Division
Miami, Florida, USA
CSU/CIRA
April 2nd, 2004Co-Authors: Craig Anderson, Noel Charles, Gil Clark, Peter Dodge, Jason Dunion,
Jose Fernandez-Partagas, James Franklin, Paul Hungerford, Charlie Neumann, Mark Zimmer, and the NHC Best Track Change Committee
Acknowledgments: Sim Aberson, Auguste Boissonnade, Emery Boose, Mike Chenoweth, Hugh Cobb, Jose Colon, Neal Dorst, Paul Hebert, Brian Jones, Lorne
Ketch, Cary Mock, Ramon Perez Suarez, David Roth, Al Sandrik, and David Vallee.
What is the historical hurricane database and how is it utilized?
Why revise HURDAT and how is it done?Databases providedResults thus far:
– Example: The 1886 Indianola Hurricane– 1851 to 1910– Hurricane Andrew
The Atlantic Hurricane The Atlantic Hurricane Database Re-analysis ProjectDatabase Re-analysis Project
Acknowledgment: NOAA grant (NA7P0369), a grant from the Risk Prediction Initiative and supplemental funding from the Insurance Friends of NHC
NOAA Dork LogoNOAA Dork Logo Track andIntensity Forecast
Developmentand
Verification
Climate Variability and Change Studies
Building Codes andInsurance Rates
HURDAT -Developed in the
late 1960s in support of the Apollo
space program
Hurricane Bret (1999)
Intensity Estimates and “Best Track” Values
Center Fix and “Best Track”
Jarvinen et al. (1984)
Smoothed Representation in Best Track
Neumann et al. (1999)
Observational Platforms for Atlantic Hurricanes
Incorrect intensity
and location at landfall
Too Rapid DuringLast 6 Hours
Pressure-Wind Relationship
Atlantic Major Hurricanes
Landsea (1993)
Bias-removed
Franklin and Black (1999)
Mean Wind ProfileWind in Hurricane Georges
GPS DropsondesGPS Dropsondes Measures the wind around and in hurricanes
from the aircraft to the ocean’s surface
Work of Jose Partagas: Historical Reconstruction from 1851-1910
ShipTracks
Using ShipObservations to
Estimate theHurricane’s
Location
Estimating Intensity with and without Aircraft Reconnaissance
The Beaufort Wind ScaleBeaufort Knots Description Number
0 < 1 Calm
1 1-3 Light air
2 4-6 Light breeze
3 7-10 Gentle breeze
4 11-16 Moderate breeze
5 17-21 Fresh breeze
6 22-27 Strong breeze
7 28-33 Near gale
8 34-40 Gale
9 41-47 Strong gale
10 48-55 Storm
11 56-63 Violent storm
12 > 63 Hurricane
ATLANTIC WIND/PRESSURE RELATIONSHIPS
Winds (knots) computed from regional P/W relationships
Estimated central pressure from Ho (1989) of 915 mb at landfall in Texas is incorrect since it relied upon a pressure measurement from San Antonio, Texas, which has been found to be a surface pressure rather than a sea level pressure value. Additionally, it is likely that this was not a central pressure measurement either as strong winds were still observed at the time of lowest pressure and that winds only shifted from northeast to southeast. This sea level pressure measurement of 971 mb (corrected from the 948 mb surface pressure value) at 19Z on the 20th implies a central pressure of around 965 mb, assuming that the RMW estimate of Ho (of 12 nmi) is slightly too small (15 nmi utilized instead). 965 mb suggests winds of 94 kt from the Gulf of Mexico wind-pressure relationship for a marine exposure - 85 kt utilized in best track for this inland location. Using methodology in Ho et al. (1987) as modified by B. Jarvinen (personal communication), a 6.5 hr transit time from landfall to a position near San Antonio, and the 965 mb central pressure near San Antonio, a new value of 925 mb at landfall is estimated for this hurricane. This suggests winds of 133 kt from the Gulf of Mexico wind-pressure relationship. The estimate of 15 nmi for RMW is slightly smaller than climatology (18 nmi) for this latitude and central pressure (Vickery et al. 2000), supporting slightly stronger winds for this particular storm. 135 kt is chosen as the maximum sustained winds at landfall. This is consistent with the very high storm tide and extreme destruction in Indianola, Texas. Storm surge modeling efforts with the SLOSH model (B. Jarvinen, personal communication) indicate that a 925 mb central pressure and RMW of 15 nmi provides reasonable matches to observed surge values. Positions are altered slightly after landfall to better account for passage of the hurricane's center near San Antonio at 19Z on the 20th. A storm tide of 15' was reported for Indianola, Texas in Roth (1997b).
Metadata File for Storm #5, 1886:
1886/05 (Synoptic/intensity):
Date Time Wind/Dir Pressure Location Source
8/14/1886 ???? UTC 80 kt/ESE-SW ???? mb 17.7N 67.5W "Gertie M. Rickerson"
Minutes of the NHC best-track change commmittee meeting
Members Jack Beven, Jim Gross, Richard Pasch, Ed Rappaport, and chair (Colin McAdie) present. (meeting 5 – 22 March, 2002)
The committee met to continue consideration of the most recent set of best-track changes provided by Chris Landsea et al. The committee resumed discussion with storm 1 of 1897, as agreed, completed discussion on the second third (1890-1899) of the material and then proceeded through storm 5 (becoming 6) of 1901.
Jack Beven noted that the use of 3- or 4-cup anemometers in the early portion of the record could affect wind estimates. Although there may be a systematic way to handle this, it is not clear whether this has been accounted for.
< Yes, this has been accounted for as best possible. In use during the period being revised - 1851 to 1910,
though anemometers were mainly available from the 1870s onward at coastal stations - was the four
cup Robinson anemometer. However, the primary difficulties with this instrument were its calibration and its
mechanical failure in high wind conditions. Even as late as 1890, the highest wind that could be reliably
calibrated with this instrument was only about 30 kt (from a whirling machine), due to lack of a strict
comparison with a known quantity of stronger winds (Fergusson and Covert 1924)…. >
Estimated average position and intensity errors in best track for the years 1851-1910. Negative bias errors indicate an underestimation of the true intensity._________________________________________________________________________ Situation Dates Position Intensity Error Intensity Error
Error (absolute) (bias)_________________________________________________________________________Open ocean 1851-1885 120 nmi/220 km 25 kt/13 m s-1 -15 kt/-8 m s-1
1886-1910 100 nmi/185 km 20 kt/10 m s-1 -10 kt/-5 m s-1
Landfall in 1851-1885 120 nmi/220 km 25 kt/13 m s-1 -15 kt/-8 m s-1 unsettled area 1886-1910 100 nmi/185 km 20 kt/10 m s-1 -10 kt/-5 m s-1
Landfall at 1851-1885 60 nmi/110 km 15 kt/8 m s-1 0 kt/0 m s-1
settled area 1886-1910 60 nmi/110 km 12 kt/6 m s-1 0 kt/0 m s-1
#/Date Original 2003 HURDAT Category/State HURDAT Revision Changes
2-8/1/1899 TS AFL2 Upgrade by two categories 3-8/18/1899 NC3 NC3 No change 8-10/31/1899 NC3,SC3 NC2,SC2 Downgrade by a category 1-9/9/1900 CTX4 CTX4 No change 3-7/11/1901 NC1 NC1 No change 4-8/14-15/1901 LA2,MS2 LA1,MS1,AL1 Downgrade by a category, add in Alabama 1902 - No U.S. hurricanes 3-9/11&13/1903 CFL2,AFL1 CFL1,AFL1 Downgrade by a category in SE Florida 4-9/16/1903 NJ1,NY1 NJ1,DE1 No change in category, add in Delaware, remove New York 2-9/14/1904 SC1 SC1 No change 3-10/17/1904 TS CFL1 Upgrade by a category 1905 - No U.S. hurricanes 2-6/17/1906 CFL1 BFL1,CFL1 No change in category, add in SE Florida 5-9/17/1906 SC3,NC3 SC1,NC1 Downgrade by two categories 6-9/27/1906 MS3,AL3 MS2,AL2,AFL2,LA1 Downgrade by a category, add in NW Florida and Louisana 8-10/18/1906 CFL2 BFL3,CFL3 Upgrade by a category, add in SW Florida 1907 - No U.S. hurricanes 3-7/31/1908 NC1 NC1 No change2-6/29/1909 TS ATX2 Upgrade by two categories 4-7/21/1909 CTX3 CTX3 No change 6-8/27/1909# ATX2 ATX1 Downgrade by a category 8-9/21/1909 LA4 LA3,MS2 Downgrade by a category, add in Mississippi 10-10/11/1909 CFL3 BFL3,CFL3 No change in category, add in SW Florid3-9/14/1910 ATX2 ATX2 No change 5-10/17/1910 BFL3 BFL2 Downgrade by a category
The Re-analysis The Re-analysis of Hurricane Andrew (1992)of Hurricane Andrew (1992)
Revised Best Track
A RE-ANALYSIS OF ANDREW’S INTENSITY
1992’s Hurricane Andrew originally was assessed as a Category 4 hurricane, based primarily upon extrapolation of flight-level winds to the surface.
Research using GPS dropwindsondes in the late 1990s and early 2000s has demonstrated that stronger winds exist at the surface the hurricane eyewall than originally believed.
A re-analysis indicates that Hurricane Andrew reached Category 5 status at its landfall in both the northern Bahamas and in southeastern Florida (145 kt +10 kt).
Because of this reclassification, the return period of catastrophic hurricanes like Andrew increases from about 30 years to around a century for southeastern Florida. Thus the risk from Andrew-like hurricanes there is significantly LESS than previously estimated.
What is the historical hurricane database and how is it utilized?
Why revise HURDAT and how is it done?Databases providedResults thus far:
– Example: The 1886 Indianola Hurricane– 1851 to 1910– Hurricane Andrew
The Atlantic Hurricane The Atlantic Hurricane Database Re-analysis ProjectDatabase Re-analysis Project
Acknowledgment: NOAA grant (NA7P0369), a grant from the Risk Prediction Initiative and supplemental funding from the Insurance Friends of NHC
“Settled Area” In 1890
Atlantic Multidecadal ModeLocal Correlation of SST versus REOF
Mestas-Nunez and Enfield (1999)
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
SS
T (°
C)
1870
1874
1878
1882
1886
1890
1894
1898
1902
1906
1910
1914
1918
1922
1926
1930
1934
1938
1942
1946
1950
1954
1958
1962
1966
1970
1974
1978
1982
1986
1990
1994
1998
Atlantic SST Multidecadal Mode (AMM) (rotated)
Annual means and 5-year RM for N. Atlantic Box from Goldenberg et al. Science, July 20, 2001
WHAT IS THE INTENSITY OF A TROPICAL WHAT IS THE INTENSITY OF A TROPICAL CYCLONE AND HOW IS IT MEASURED TODAY?CYCLONE AND HOW IS IT MEASURED TODAY?
Maximum sustained surface wind: Maximum wind, averaged over 1 minute interval at an altitude of 33 ft (10 m), associated with the circulation of the tropical cyclone at a given point in time.
With very, very few exceptions, direct observations of the maximum sustained surface wind in a tropical cyclone are not available.
Satellite imagery using the Dvorak techniqueAircraft reconnaissance flight-level winds
GPS dropwindsondes
EYEWALL STRUCTURE CAN VARY SIGNIFICANTLY FROM STORM TO STORM, OR EVEN DURING DIFFERENT STAGES OF THE LIFE CYCLE OF A SINGLE STORM.