WORLD METEOROLOGICAL ORGANIZATION
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TCM-VI/Doc. 4.6.1
(9.X.2009)
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SIXTH TROPICAL CYCLONE RSMCs/TCWCs
TECHNICAL COORDINATION MEETING
ITEM 4.6.1
BRISBANE, AUSTRALIA
2 TO 5 NOVEMBER 2009
ENGLISH ONLY
International Best Track Archive for Climate Stewardship (IBTrACS)
(Submitted by Ken Knapp, NOAA’s National Climatic Data Center)
This document outlines the history and background, need for, goals, and accomplishments
of the International Best Tracks Archive for Climate Stewardship (IBTrACS) dataset as a
tool in support of the WMO TC Programme for use by all TC RSMCs and TCWCs. The
IBTrACS effort began in late-2007 as a project under the auspices of the World Data Center
for Meteorology–Asheville; which is housed at NOAA’s National Climatic Data Center, and
has evolved and progressed significantly since then.
The goal of IBTrACS is to collect the historical tropical cyclone (TC) best track data from all
available international centers and other agencies, combine the disparate datasets into one
product and disseminate in formats used by the TC community. Each TC RSMC and TCWC
forecasts and monitors storms for a specific region and annually develops and archives best
track data, which consist of information on a storm’s position, intensity, and other related
parameters. Therefore, IBTrACS is a new global dataset based on the best track data from
numerous sources. Moreover, rather than preferentially selecting one track and intensity for
each storm, the mean position, the original intensities from the agencies and summary
statistics are all provided.
The ultimate goal is for IBTrACS to be officially recognized by the WMO TC Programme as
a as a diagnostic and research tool for use by all RSMCs and TCWCs. To that end, we are
also looking for guidance from the WMO’s international centres to report updates to
historical tracks, and provide input on new track data to IBTrACS on a regular basis, with
the eventual goal of having a uniform set of best tracks reporting procedures to aid in a
higher quality, comprehensive global best track dataset.
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Action proposed
The Meeting is invited to note the information in this document with a view toward:
a) Providing any advice and recommendations for improvements and/or enhancements
to IBTrACS.
b) Endorsing the IBTrACS dataset as a viable, active, and unifying global archive to aid
the work of the TC RSMCs and TCWCs.
c) Formally adopting IBTrACS by the WMO TC Programme for use as the recognized
global best tracks archive for TCs.
d) Working towards developing standard operational procedures across the TC RSMCs
and TCWCs to aid in standardizing the data archived in IBTrACS.
e) Inviting IBTrACS to provide updates to the TC Programme as appropriate.
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A.
Background and Overview
Studies of tropical cyclone frequency and distribution have garnered much attention recently.
Despite the numerous articles in peer-reviewed literature discussing global statistics of
tropical cyclones (e.g., power dissipation index or frequency of extreme cyclone s), until
recently there was no such central repository of global tropical cyclone data. Many
researchers have simply used data from the fewest sources to obtain global coverage:
HURDAT1 and data from the Joint Typhoon Warning Center. Aside from the many issues in
merging data from just these two centers, doing so also excludes data from many of the
WMO-recognized Regional Specialized Meteorological Centres (RSMC), who officially
forecast and monitor tropical cyclones in their region of responsibility. Furthermore, there are
similar best track data sets from other institutions in countries with interests in certain basins.
In short, the two primary issues which hinder scientists from using all available global tropical
cyclone data are: 1) availability and 2) the process in combining disparate data sets. The
purpose of the International Best Track Archive for Climate Stewardship (IBTrACS) project
(Knapp et al., 2010) is to overcome these issues thereby facilitating scientific research to 1
improve the public understanding of global tropical cyclones. First, we work with all available
RSMCs and other centres of data to obtain the global best tracks. Second, we process all
best track data by combining storm information tracked by multiple centres (Kruk et al. 2009)
and reporting the data using common formats. The overarching vision is to provide an openly
accessible and comprehensive global tropical cyclone best track data set to facilitate
research. Likewise, the methods used to produce the data are openly described and flexible
to accommodate user feedback.
More information on IBTrACS is available on the project website at
http://www.ncdc.noaa.gov/oa/ibtracs/.
B.
Needs
C.
Goals and Accomplishments
NOAA’s National Climatic Data Center (NCDC) hosted an international “IBTrACS Workshop”
on May 5-7, 2009 in Asheville, NC (Levinson and Diamond 2009). The purpose of the
workshop was to gather international experts in global tropical cyclone best track data to
discuss a variety of topics that would serve to enhance the existing IBTrACS global tropical
cyclone dataset. The format of the workshop was one to three presentations on a specific
topic relevant to best track dataset development followed by moderated discussion amongst
the participants in break-out groups over the course of two and a half days. In addition to
invited presentations, abstracts for a poster session were also accepted, and the session
featured relevant topics to global best track data improvements and enhancements. In
summary, this was the first time that the IBTrACS Project team at NCDC had an opportunity
to interact with the various experts and the official tropical cyclone monitoring and forecast
centers from around the world, and as such the prime outcome was the establishment of a
core group of contributors and users to aid in furthering the development and future releases
of the IBTrACS dataset. Attendees spanned the globe from places such as Australia, Fiji,
Guam, India, New Zealand; as well as from across the U.S.
To quote from two prominent authorities on tropical cyclones in attendance:
Hurricane Database (HURDAT) data is produced by NOAA’s Atlantic Oceanographic and
Meteorological Laboratory (AOML)
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"It was a pleasure to be involved. I am really pleased to see you folks taking on the effort of
producing a global data set. And the overall discussions at the meeting were a valuable
exchange of information on real issues associated with cyclone data archiving....I really hope
that you can follow up in a year or two with a second get together...perhaps even in
association with the next IWTC." – Dr. Greg Holland, Director Mesoscale and Microscale
Meteorology Division, NCAR, Boulder, CO.
“I thought that the workshop went great - lots of excellent discussion and some fairly
concrete ideas of how to proceed.” – Dr. Chris Landsea, Science and Operations Officer,
NOAA’s National Hurricane Center.
D.
Summary
The IBTrACS dataset is the result of a globally coordinated and collaborative project, and
provides the first publicly available centralized repository of global TC best track data from
the RSMCs and other agencies. In combining the disparate datasets, I BTrACS uses
objective techniques that necessarily account for the inherent differences between
international agencies. Unlike any other global tropical cyclone best track dataset, IBTrACS
provides a measure of the inter-agency variability, which helps to identify uncertainty in the
TC record. While IBTrACS is not a reanalysis (e.g., Fernandez-Partagas and Diaz,1996;
Harper et al., 2008b; Landsea et al., 2004), the derived uncertainty metrics can serve as a
stepping stone in identifying those tropical cyclones which are in most need of reanalysis. As
IBTrACS data stand, numerous inhomogeneities exist in the intensity record due to interagency
differences in available technologies, observations and procedures over time. For
example, inhomogeneities were introduced when various satellite data became available at
an agency or when forecasters were trained in different analysis techniques. As discussed in
Levinson et al. (2009), efforts are underway at NCDC to document the operating procedures
at the various RSMC and forecast offices, with an emphasis on changes in processes or
capabilities that affect dataset homogeneity.
Finally, IBTrACS is expandable to allow for inclusion of other best track datasets as they
become available. This allows input from individuals and/or agencies that have yet to
develop new or release existing best track data . It is clear that the IBTrACS dataset would
be even more useful by including other information on global tropical cyclones. For example,
non-developing storm tracks could be included for the tropical cyclone forecasting community
in a future version. Such data are needed to verify statistical tropical cyclone intensity
prediction models (e.g., DeMaria and Kaplan, 1999). Furthermore, some agencies provide
non 6-hr analyses and other storm parameters (such as radius of maximum winds, storm
size, eye diameter, and radius of the outer-most closed isobar), which could be incorporated
into IBTrACS making it more useful to storm surge and wave modelers, emergency
managers and reinsurance groups.
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E.
References
DeMaria, M. and J. Kaplan, 1999: An Updated Statistical Hurricane Intensity Prediction
Scheme (SHIPS) for the Atlantic and Eastern North Pacific Basins. Weather and
Forecasting, 14, 326-337.
Fernandez-Partagas, J. and H. F. Diaz, 1996: Atlantic Hurricanes in the Second Half of the
Nineteenth Century. Bulletin of the American Meteorological Society, 77, 2899-2906.
Harper, B. A., S. A. Stroud, M. McCormack, and S. West, 2008b: A review of historical
tropical cyclone intensity in north-western Australia and implications for climate change trend
analysis. Australian Meteorological Magazine, 57, 121-141.
Knapp, K. R., M. C. Kruk, D. H. Levinson, H. J. Diamond, and C. J. Neumann, 2010: The
International Best Track Archive for Climate Stewardship (IBTrACS): Centralizing tropical
cyclone best track data. Bulletin of the American Meteorological Society, In press.
Kruk M.C., K.R. Knapp, and D.H. Levinson (2009): A technique for combining global tropical
cyclone best track data. Journal of Atmospheric and Oceanic Technology (in press).
http://ams.allenpress.com/perlserv/?request=get-pdf&doi=10.1175%2F2009JTECHA1267.1
Landsea, C. W., C. Anderson, N. Charles, G. Clark, J. Dunion, J. Fernandez-Partagas, P.
Hungerford, C. Neumann, and M. Zimmer, 2004: The Atlantic hurricane database reanalysis
project: Documentation for the 1851-1910 alterations and additions to the HURDAT
database. Hurricanes and Typhoons: Past, Present and Future, R. J. Murnane
and K.-B. Liu, Eds., Columbia University Press, 177-221.
Levinson, D.H., and H.J. Diamond, 2009: Combining Tropical Cyclone Datasets Worldwide.
Eos, Transactions, 90 (35), 301.
Levinson, D. H., H. J. Diamond, K. R. Knapp, M. C. Kruk, and E. J. Gibney, 2009: Toward a
homogenous global tropical cyclone best track dataset. Bulletin of the American
Meteorological Society, Submitted.