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Cyclone Exchange
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Cyclone Exchange
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The Sixth WMO International Workshop on Tropical Cyclones recommended that all tropical cyclone-related Numerical Weather Prediction (NWP) products, including full set of ensemble forecasts, be made available to all operational and research users in real-time. Meanwhile, the THORPEX GIFS-TIGGE Working Group is developing plans for the Global Interactive Forecast System (GIFS) for the real time dissemination of ensemble data and products in support of high impact weather prediction, including prediction of tropical cyclones. A pilot project has been established by the TIGGE Working Group to test the real-time exchange of ensemble TC track forecasts; the format for TC data exchange will be Cyclone XML (CXML). Exchange of real-time TC forecasts was done in the THORPEX Pacific-Asian Regional Campaign (T-PARC) (August 2008-March 2009), designed to study the lifecycle of tropical and extratropical cyclones over the northern Pacific. CXML is being used in the North Western Pacific Tropical Cyclone (TC) Ensemble Forecast project which provides near real time ensemble forecasts of TCs based on the TIGGE dataset. Ongoing exchange of TC tracks in real time is expected to lead to improved tropical cyclone prediction, benefiting society in general.
The table below lists FTP sites from which it is possible to download real-time ensemble tropical cyclone track forecasts. A more sophisticated web interface will be developed in due course.
To make collection and combination of track forecasts easier, the WMO standard file naming convention has been followed. The standard naming convention for ensemble TC track forecast files is similar to the existing TIGGE file name convention, and has the form:
z_tigge_c_cccc_yyyyMMddhhmmss_nnn_mmmm_vvvv_pppp_bbb.xml[.compression]
(to be confirmed)
where
Click here
to learn more about CXML, including
how to read CXML files.
Click here
to see what a sample ensemble TC
track forecast written in CXML format looks like (courtesy of Piers Buchanan, Met Office).
Tropical cyclones
CMC and NCEP -
How the NCEP tropical cyclone tracker works (Tim Marchok,
2002 AMS Conference on Hurricanes and Tropical Meteorology)
CMA -
ECMWF -
Tropical cyclone forecasting at ECMWF: new products and validation
(Gerald van der Grijn, 2002 ECMWF Tech. Mem. 386)
JMA -
KMA -
UKMO -
Met Office forecast tracks verification method
(based on article in Dec 1994 NWP Gazette)
Extra-tropical cyclones
CMC and NCEP - The NCEP extra-tropical tracker is similar to the tropical cyclone tracker,
but extra-tropical cyclones are identified using mean sea level pressure
while more parameters are used for TCs.
Tracking uses a combination of wind vectors and linear extrapolation.
(Marchok, 2002)
CMA -
ECMWF and UKMO - First θw at 1 km is used to
identify fronts, then vorticity is used to identify and
characterise developing cyclones along the fronts.
Barotropic lows are identified from
vorticity alone. Tracking uses a combination of steering level wind,
extrapolation and lifecycle information
(Hewson and Titley, 2010)
JMA -
KMA - Cyclones are identified using mean sea level pressure. Tracking uses combination of
extrapolation (motion and p tendency) and climatological cyclone movement
(Murray and Simmonds, 1991a,
1991b)
