bias corrections of storm counts from best track data chris landsea, national hurricane center,...
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![Page 1: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/1.jpg)
Bias Corrections of Storm Counts from Best Track Data
Bias Corrections of Storm Counts from Best Track Data
Chris Landsea, National Hurricane Center, Miami, USA
Gabe Vecchi, Geophysical Fluid Dynamics Lab, Princeton, USA
Lennart Bengtsson, University of Reading, England
Tom Knutson, Geophysical Fluid Dynamics Lab, Princeton, USA
Chris Landsea, National Hurricane Center, Miami, USA
Gabe Vecchi, Geophysical Fluid Dynamics Lab, Princeton, USA
Lennart Bengtsson, University of Reading, England
Tom Knutson, Geophysical Fluid Dynamics Lab, Princeton, USA
6 May, 2009
IBTrACS Workshop
6 May, 2009
IBTrACS Workshop
![Page 2: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/2.jpg)
“This record [of Atlantic tropical cyclone counts] … shows a strong, long-term relationship with tropical Atlantic August-October SST…The underlying factor appears to be the influence of (primarily anthropogenic) forced large-scale warming.”
![Page 3: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/3.jpg)
“Although wind estimates prior to the 1940s are problematic, detection of the existence of tropical cyclones is less so,because without aircraft and satellites towarn them off, ships often encounteredstorms at sea, at least peripherally. A reasonably reliable record of annual North Atlantic tropical cyclone counts is thus available back into the late nineteenth century.” --- Mann and Emanuel (2006)
![Page 4: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/4.jpg)
A Typical Day in 2009 – Marine Data Available
around 12 UTC
![Page 5: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/5.jpg)
A Typical Day in 2009 – Marine Data Available
around 12 UTC
![Page 6: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/6.jpg)
A Typical Day in 2009 – Marine Data Available
around 12 UTC
![Page 7: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/7.jpg)
A Typical Day in 2008 – Marine Data Available
around 12 UTC
![Page 8: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/8.jpg)
A Typical Day in 1909 – Marine Data Available
around 12 UTC
![Page 9: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/9.jpg)
Open AtlanticOcean Differences
1933 Hurricane Season
2005 Hurricane Season
![Page 10: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/10.jpg)
Tropical Storm and Hurricane Numbers – A Very Large Trend over a Century
7
12
![Page 11: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/11.jpg)
2007 Hurricane Season - 16 Tropical Storms & Hurricanes……9 of which were very short-lived (< 36 hr)
![Page 12: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/12.jpg)
New Tools and Technologies ~ Additional TCs lately?
AMSU TroposphericTemperatures
Hart’s Cyclone PhaseSpace Analyses
Quikscat Surface Vectors
![Page 13: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/13.jpg)
“If it was quite marginal as to whether or not a storm would be upgraded to tropical storm status or equivalent, that decision would likely be influenced by proximity to possible impacts on land within the next 48 hours or so. That is, I suspect that the margin of acceptable error for most of us would be a little larger over the open sea as compared to potential landfall for such storms that are not all that strong anyway.”
Bob Sheets, National Hurricane Center Director, 1987-1995
Changes in “Naming” Criteria
![Page 14: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/14.jpg)
Six weak, short-lived storms in
last two seasons –
Unlikely to have been “named”
previously
![Page 15: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/15.jpg)
1900-1943: Only Ships and Coastal Stations
![Page 16: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/16.jpg)
1944-1965: Aircraft Reconnaissance Available
![Page 17: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/17.jpg)
1966-2001: Geostationary Satellite Imagery Available
![Page 18: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/18.jpg)
2002 onward: AMSU, QuikScat, Cyclone Phase Space, Advanced Dvorak
![Page 19: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/19.jpg)
Big Upward Trend – Consistent with Technological Improvements
![Page 20: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/20.jpg)
Tropical Storm and Hurricane Numbers – A Very Large Trend over a Century
7
12
![Page 21: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/21.jpg)
Tropical Storm and Hurricane Numbers - Trend Nearly Gone after Removal of Very Short-Lived Cyclones
78
![Page 22: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/22.jpg)
Atlantic ship traffic changes
Vecchi and Knutson (2008)
![Page 23: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/23.jpg)
Estimated Number of “Missed” Tropical Storms and Hurricanes of Medium to Long Duration
2-3 per year in 1880s
1-2 per year in 1900s
<1 per year in 1950s
![Page 24: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/24.jpg)
Tropical Storm and Hurricane Numbers –Upward Trend Gone After Adding in “Missed” and Removing Very Short-Lived Cyclones
98
![Page 25: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/25.jpg)
Bias Corrections of Storm Counts from Best Track Data
Bias Corrections of Storm Counts from Best Track Data
Chris Landsea, National Hurricane Center, Miami, USA
Gabe Vecchi, Geophysical Fluid Dynamics Lab, Princeton, USA
Lennart Bengtsson, University of Reading, England
Tom Knutson, Geophysical Fluid Dynamics Lab, Princeton, USA
Chris Landsea, National Hurricane Center, Miami, USA
Gabe Vecchi, Geophysical Fluid Dynamics Lab, Princeton, USA
Lennart Bengtsson, University of Reading, England
Tom Knutson, Geophysical Fluid Dynamics Lab, Princeton, USA
6 May, 2009
IBTrACS Workshop
6 May, 2009
IBTrACS Workshop
![Page 26: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/26.jpg)
![Page 27: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/27.jpg)
Enfield and Cid (2009)
Residual Atlantic Multidecadal Oscillation
North Atlantic SSTs and Quadratic Trend
![Page 28: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/28.jpg)
![Page 29: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/29.jpg)
![Page 30: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/30.jpg)
““[The National Hurricane Center] seems to be naming a lot more than they used to. This year, I would put four storms in the very questionable category, and maybe even six. In the past, we would have waited to see if another observation supported naming the system. We would have been a little more conservative."
Neil Frank, National Hurricane Center Director, 1974-1987
Changes in “Naming” Criteria
![Page 31: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/31.jpg)
![Page 32: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/32.jpg)
Landsea and Bengtsson (2008)
Frequency of Tropical Cyclones in Today’s Climate
Today’s Climate
![Page 33: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/33.jpg)
Landsea and Bengtsson (2008)
Frequency of Tropical Cyclones in Today’s Climate…Based upon Differing Thresholds of Duration
![Page 34: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/34.jpg)
Global Warming and Hurricanes:Theory and Modeling Work Suggest 2% wind increase with a
DECREASE in frequency by late 21st Century
Knutson et al. (2008)
![Page 35: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/35.jpg)
Landsea and Bengtsson (2008)
Frequency of Tropical Cyclones in Today’s Climate
Today’s Climate Bengtsson et al. (2007)
![Page 36: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/36.jpg)
Landsea and Bengtsson (2008)
Frequency of Tropical Cyclones in Today’s Climate Versus Global Warming Climate
Today’s Climate Late 21st Century Bengtsson et al. (2007)
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Maximum Potential Intensity ChangeAtlantic Basin: +1% stronger per oC SST change
Vecchi and Soden (2007)
![Page 38: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/38.jpg)
Knutson and Tuleya (2004)
![Page 39: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/39.jpg)
Increased Wind Shear from Global Warming
Vecchi and Soden (2007)
![Page 40: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/40.jpg)
What does the Atlantic hurricane database
(HURDAT) show for changes in time of tropical cyclone
frequency?
![Page 41: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/41.jpg)
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Satellite era -59% strike land
![Page 44: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/44.jpg)
Pre-satellite era -75% strike land
![Page 45: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/45.jpg)
A Typical Day in 1909 – Marine Data Available
around 12 UTC
![Page 46: Bias Corrections of Storm Counts from Best Track Data Chris Landsea, National Hurricane Center, Miami, USA Gabe Vecchi, Geophysical Fluid Dynamics Lab,](https://reader030.vdocuments.us/reader030/viewer/2022032606/56649e875503460f94b8ad45/html5/thumbnails/46.jpg)
Atlantic Hurricane Database Re-Analysis Project
"Florida's Hurricane History"
http://www.aoml.noaa.gov/hrd/data_sub/re_anal.html
1851 through 1920 changes accepted and officially adopted by NHC. 1921 through 1925 will be made available shortly. Remainder of 20th Century currently being reanalyzed.
RE-ANALYSES NEED TO BE CONDUCTED GLOBALLY!!!