15-20 nov. 20107 th iwtc, la reunion island1. 15-20 nov. 20107 th iwtc, la reunion island2 ken knapp...
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Special Focus Session 2b:IBTrACS Activities and Updates
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International Best Track Archive for Climate Stewardship
Ken KnappDavid Levinson
Michael KrukHoward Diamond
Ethan GibneyPaula Hennon
Carl Schreck, IIINOAA/NCDC
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1630 -1645 IBTrACS Introduction
Discussions: 1645 – 1705 Best track parameters &
data quality 1705 - 1725 Best track continuity 1725 - 1745 Global Reanalysis
Conclusions: 1745 - 1800 IBTrACS wrap up
Outline
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Introduction
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Reanalysis using:◦ current understanding ◦ new techniques
WMO◦ Incorporate BT datasets into unified database◦ Make more homogeneous◦ Include metadata◦ New working group
BT experts define standards Establish reanalysis procedures
Operational agencies◦ Continue revising historical BT data◦ Denote how BT data were derived (e.g., wind/pres.)◦ Uncertainties in BT record should be determined and recorded
IWTC-VI – Costa Rica, 2006: Recommendations
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International◦ Many nations and agencies working together
Best Track◦ Information on tropical cyclones◦ Enormous impact on life and property worldwide
Archive◦ One-stop-shop
Climate◦ Global distribution◦ Cyclone intensity◦ Temporal variability
Stewardship◦ Maintaining data for future generations
What is IBTrACS?
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What IBTrACS is not …◦ A reanalysis◦ Absolutely, every storm, that ever occurred
What IBTrACS is…◦ Collection◦ Combination◦ Collaboration◦ Centralization◦ Scalable◦ WMO-recognized
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Data providers:◦ RSMCs: CPHC, IMD, JMA, La Reunion, Nadi, NHC◦ TCWCs: BoM, Wellington◦ Other: HKO, JTWC, CMA/STI
At WDC:◦ IBTrACS Team
Around the world:◦ Users providing feedback
IBTrACS: Who we are
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IBTrACS Data FormatsMultiple intensities possible 1 intensity per report
netCDF CSV
WMO HURDAT ATCF cXML GIS shapefile
Ver
. 1 Mean position
Mean intensityMean position JAOTMean intensity Kruk et al., 2010
Ver
. 2 Mean position BAMS
Mean intensity Knapp el al., 2010
Mean positionMean intensityOriginal positions & intensity
Ver
. 3 Original positions & intensityOther parameters as available
WMO position In prep.WMO intensity
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IBTrACS: By the numbers 14 sources 31,002 total tracks 500,000+
observations
~11,774 storms 6757 TCs with MSW>30
1848-2009 1907-2009
1877-2009
1884-2009
1949-2009
1851-2009
1848 - 2009
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5-7 May 2009 Participants worldwide Topics
◦ Operational Best tracking procedures◦ Wind-pressure relationships◦ Wind speed conversions◦ Global Reanalysis◦ IBTrACS improvements
Meeting summary in March 2010, BAMS
IBTrACS Workshop
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The IBTrACS team should…◦ Document BT procedures,
Work with agencies Through a survey
◦ Provide all parameters as provided by original agency in IBTrACS
◦ Distribute official and unofficial datasets of other TC related data
◦ Archive all ancillary data◦ Get involved with the IWTC
IBTrACS Workshop recommendations
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Best tracking agencies should …◦ Report more parameters and use WMO format
◦ Document current and historic BT practices
◦ Standardize definitions of winds and wind conversions
◦ Rescue and archive documents relevant to BT data
◦ “Best track” throughout life cycle (through ET)
◦ Encourage best track data discussions at IWTC
IBTrACS Workshop recommendations
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Best Track Parameters and
Data Quality
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A balancing act…
User needs
AvailableData
Forecaster/Analyst
Time
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Storm name 11 ü ü ü ü ü ü ü ü ü ü üDate 15 ü ü ü ü ü ü ü ü ü ü ü ü ü ü üTime 15 ü ü ü ü ü ü ü ü ü ü ü ü ü ü ülatitude 15 ü ü ü ü ü ü ü ü ü ü ü ü ü ü ülongitude 15 ü ü ü ü ü ü ü ü ü ü ü ü ü ü ü
max avg wind speed 14 ü ü ü ü ü ü ü ü ü ü ü ü ü ücentral pressure 13 ü ü ü ü ü ü ü ü ü ü ü ü ücyclone type 13 ü ü ü ü ü ü ü ü ü ü ü ü üWind Radii by quadrant 5 ü ü ü ü üsource code 4 ü ü ü üRMW 4 ü ü ü üRMW quality 3 ü ü üpos_confidence 3 ü ü üwind units 3 ü ü üT-number 3 ü ü üCI-number 2 ü ütime interval for ws avg 2 ü ümax gust 2 ü üpressure quality 2 ü üunits of length 1 ügust period 1 üwind quality 1 ü ROCI 3 ü ü üEye diameter 3 ü ü üPressure _OCI 2 ü ü
# of Variables provided from WMO 17 10 7 3 3 3 3 3 4 4 2 3 9 5
Parameters in useW
MO
Par
amet
ers
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From all agencies◦ Time, Latitude, longitude◦ Wind & Pressure◦ Cyclone type
From some agencies◦ Wind radii (5)◦ Radius of Maximum Winds (4)◦ Radius of outermost closed isobar (3)◦ Pressure of outermost closed isobar (2)◦ Dvorak Parameters: T-num and CI (2)
Parameter summary
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IBTrACS requested users to identify their needs
Results…◦ Storm size information
RMW, Wind radii, ROCI◦ Higher temporal resolution
More the just 6 hourly Landfall, maximum intensity, etc.
User needs…
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Based on the WMO best track format parameters, which parameter could be most easily added to the BT record from your agency?
What next parameter would be of the most use for users? (researchers, etc.)
What would it take to add:◦ Confidence flags?◦ Quality indicators?
Best Track Parameter Questions:
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Best Track Continuity
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An attempt to record historical operational “best tracking” practices
Questions include:◦ Are best track positions smoothed? If so, how?◦ Which year did your agency first begin acquiring
SSM/I (other microwave imagery)?◦ What other changes to in situ, radiosondes or
remote sensing data affected forecast and best tracking capability?
◦ How was the cyclone maximum sustained wind speed determined?
IBTrACS Community Survey
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“There are limits to how precisely we can measure the locations and intensities even with in situ data, and the in situ sampling can be problematic. These problems get progressively worse the farther back in time one looks in the data. Satellite observations don’t exist before the 1960’s, and in situ data becomes far less systematic with time when looking back.”
Survey response:
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Source of Best Tracks
Year Paper
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1959 (Chan and Shi, 1996) WP X
Var. (Henderson-Sellers et al., 1998) Global X X
1966 (Lander and Guard, 1998) Global X X
1958 (Emanuel, 2000) NA/WP X X
1945 (Emanuel, 2005) Global X X
1970 (Webster et al., 2005) Global X X X
1960 (Chan, 2006) WP X
1965 (Wu et al., 2006) WP X X X
1986 (Klotzbach, 2006) Global X X X
1970 (Hui et al., 2007) WP X X X
1989 (Knaff and Zehr, 2007) Global X X
1983 (Kossin et al., 2007) Global X X
1969 (Kuleshov et al., 2008) SH X X X
1979 (Lau et al., 2008) NA/WP X X
1945 (Lowry et al., 2008) WP X X X X
1965 (Wang et al., 2008) WP X X
IBTrACS Global X X X X X X X X X X X X
What areresearchersusing?
19441945195819601964196519651965197019701986
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Regarding JTWC: Chu et al. 2002
◦ “The authors rate the 1985-2000 best-tracks to be of high quality and urge users to use older data with caution.”
Could a similar analysis be performed for other agencies/basins?
Data continuity and reliability
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Assess dataset maturity based on the data◦ In use by the satellite data community
Assessment criteria include:◦ Algorithm stability◦ Metadata & Quality Assurance◦ Documentation◦ Validation◦ Scientific Applications
Could best track data be assessed with similar criteria?
Best Tracks as aClimate Data Record
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IBTrACS 1st year Frequency Start◦ Global 1848 ?◦ NI 1877 ?◦ SI 1848 ?◦ WP 1945 ?◦ EP 1949 ?◦ SP 1907 ?◦ NA 1851 ?
What is a good starting year for analyzing TC frequency?
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What criteria are used to decide an appropriate starting year?
What is a good starting year for analyzing TC frequency?◦ When do counts become reliable?
What is a good starting year for analyzing TC intensity?◦ When do intensities become reliable?
What’s the best road forward to analyze continuity in each basin?
Questions:
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Global Reanalysis
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Number of agencies “best tracking” each storm
Combining multiple sources
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Increasing or decreasing?
Trends: Western Pacific
Emanuel, 2005
Wu et al., 2006
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Application:Prioritize Reanalysis
Maximum intensity? Accumulated uncertainty!
Western North Pacific
Year Name
1951 Marge
1952 Bess
1954 June
1959 Tilda
1969 Ida
Max MSW ( kt)
175 - 88 = 87
146 - 88 = 58
165 - 114 = 51
165 - 110 = 55
156 - 100 = 56
ΔACE(104 kt2) ΔPDI (106kt3)
40 66
20 30
25 40
23 40
21 34
Annual PDI ~ 150
175 kt @ 10-min
88kt @ 10-min
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Application: Prioritize Reanalysis
Year Name Max MSW (kt) ΔACE(104 kt2)
ΔPDI (106kt3)
1971 Sally 88 - 40 = 48 8 5
1971 Sheila/Sophia
110 - 62 = 48 8 8
1985 Isobel 84 - 44 = 40 10 8
1987 Elsie 97 - 53 = 44 8 6
1992 Irna/Jane 126 - 75 = 51 19 22
Southern Indian Ocean
Year Name Max MSW (kt) ΔACE(104 kt2)
ΔPDI (106kt3)
1972 Carlotta 97 - 57 = 40 28 23
1972 Gail 92 - 55 = 37 12 10
1972 Wendy 106 – 70 = 36 19 16
1972 Emily 92 - 57 = 35 8 7
2004 Fay 106 – 79 = 27 19 19
South Pacific
Annual PDI ~ 70
Annual PDI ~ 39
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North Atlantic◦ HURDAT reanalysis effort◦ Currently ~1940s ◦ Moving forward
South Indian Ocean (MeteoFrance)◦ Dvorak Reanalysis of AVHRR data prior to 1998
Others??
Reanalysis underway
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HURSAT-AVHRR 1978-present 4km resolution ~12 hourly netCDF
HURSAT: A tool for reanalysisHURSAT-MW 1987-present ~ 25 km resolution ~ 12 hourly (or better) netCDF & imagery
HURSAT-B1• 1978-present• 8km resolution• 3 hourly• netCDF &
MPG movies
GridSat – Globally Gridded Satellite
• 1978-present• 8km resolution• 3 hourly• netCDF
HR Mitch
HR WilmaHR IvanHR JeanneHR KarlHR Lisa
Typhoon Tip
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What data could be prepared to aid a global reanalysis?
How could the TC community start the process of a global reanalysis?
Are there overlaps/synergies that can be exploited?
How would a reanalysis best be coordinated?
Global Reanalysis Questions
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Conclusion
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http://www.ncdc.noaa.gov/oa/ibtracs/ Google: IBTrACS
Finding IBTraCS
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120+ registered users Kudos
◦ “Even though IBTrACS is still evolving, your efforts at homogenization on a global scale are very important.”
◦ “Congratulations for getting this complete and publicly available! Keep up the great work!”
Feedback◦ Error corrections◦ Parameter requests – radius maximum winds, etc.
Contact Us at [email protected]
User feedback
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Take the survey online:www.surveymonkey.com/s/ibtracs
Or complete the survey via◦ Email◦ Word document◦ Phone◦ Talk with us at a conference◦ …
IBTrACS Community Survey
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Include more variables◦ “If they provide it, so do we”◦ ROCI, RMW, Eye Diameter, T num, CI, …
Include non-developing storms◦ Forecast aid development
Document tropical cloud clusters Other agencies as available
Planned improvements
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11-15 April 2011 Honolulu, Hawaii Discussions on:
◦ Operational best tracking procedures◦ Best track parameters◦ Best track data continuity◦ User needs ◦ Global reanalysis
IBTrACS 2nd Workshop
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Backup slides
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IBTrACS structure
IBTrACS Team
RSMCsTCWCsOthers
IBTrACSData
Users
Feedback
Create data
Data access
Data providers
Feedback
Publications
Peerreview
Workshop
Recommendations
Recommendations
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Track of 1992 Typhoon Yvette
IBTrACS MergingPosition Pressure Wind Speed
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Direct interactions BT Panel
New structure ideas
WMO-recognizedIBTrACS Team
RSMCsTCWCsOthers
IBTrACSData
Users
Feedback
Create data
Data access
Data providersRecommendations
Feedback
Pubs
Peerreview
Workshops:- IWTC- IBTrACS-
Conferences
Recommendations
Recommendations
WMO-recognizedIBTrACS Team
RSMCsTCWCsOthers
IBTrACSData
Users
Feedback
Create data
Data access
Data
Feedback
Pubs
Peerreview
ResultsRecommendations
WMO-BT Expert
PanelMembership
Workshops:- IWTC- IBTrACS-
Conferences
Requirements
Recommendatio
ns
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Storms per decade
Storm frequency
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Maximum intensity
Mean Intensity (kt)
StormIntensity
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Range in wind speed (kt)
Relative range (%)
InteragencyDifferences
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Changes in interagency differences
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Interagency differences:North Indian Ocean
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Interagency differences:South Indian Ocean
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Interagency differences:South Indian Ocean through time
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Interagency differences:Western Pacific Ocean
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Interagency differences:Western Pacific Ocean through time
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Interagency differences:South Pacific Ocean
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Interagency differences:South Pacific Ocean through time
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Global coverage Geostationary and polar orbiting 1979 to present
HURSAT Samples
Cyclone Daryl-Agnielle11/21/1995 03:00 UTC
Strongest TC in Indian Ocean
885 mb
Hurricane Wilma10/19/2005 09:00 UTCStrongest TC in North
Atlantic
882 mb
Cyclone Zoe12/28/2002 03:00 UTC
Strongest TC in Southern Pacific
879 mb
Typhoon Gay (Western Pacific)11/20/1992 20:15 UTC
Strongest TC on Earth since 1979
872 mb
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More reanalysis needed… Landsea et al (2006)
hypothesize:“subjective measurements and variable procedures lead to biases in the tropical cyclone intensity record”
Support by showing 5 storms over Indian Ocean
Storms were stronger than analyzed
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Reanalyzing AVHRR
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Reanalyzing AVHRR
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