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Cyclone XML (CXML) |
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Cyclone XML (CXML) |
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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 Interactive Grand Global Ensemble (TIGGE) project 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. No generally used encoding, however, exists for the exchange of tropical cyclone related data, as the various producing centers use a variety of formats.
To facilitate easy exchange of information, a standard format to represent analyzed and forecast data for tropical and extra-tropical cyclones is proposed. The new format, called Cyclone XML (CXML) is descriptive and human-legible, making it easy for all human users and most automated applications to read. CXML is defined so it can carry data from observations and analyses, manual and NWP forecasts, multiple cyclones and multiple forecasts (ensembles). In its current version, it can include all information conveyed in other existing formats, while its flexibility and extensibility makes it simple to add new kinds of data as needed. CXML is not envisioned as a replacement for the WMO standard BUFR and CREX formats used in operational centers, but as a simple alternative.
The adoption of CXML as a standard format will not
only benefit the tropical cyclone community in general, but also the
THORPEX
community in their effort in establishing GIFS for the improved
prediction of
high-impact weather worldwide. Moreover, the use of CXML will further
the immediate goals of the THORPEX Pacific-Asian
Regional Campaign
(Sept.
2008- March 2009, T-PARC), designed to study the lifecycle of tropical
and extratropical cyclones over the northern Pacific. Ensemble
and deterministic tropical cyclone forecasts from NWP models
are now available in CXML format - please see the
THORPEX GIFS-TIGGE Cyclone Exchange page for more information.
Simple data model
Full data model
File naming convention for TIGGE TC track files - please see the
THORPEX GIFS-TIGGE Cyclone Exchange page for details
atcf2xml.pl - Perl converter from
ATCF format to CXML (Mike Charles, 8 August 2008)
read_cxml.pro - IDL CXML reader
(Beth Ebert, 8 August 2008)
cxml_fortran.tgz - Fortran95 CXML reader-writer
requiring FoX
library (Geoff Freeman, 6 April 2009)
cxml_java_demo_1-3.zip - Java CXML reader-writer
(Andrew Donaldson, 12 February 2010)
These CXML readers are not comprehensive, but will be useful to get started reading CXML. Users may need to modify the code to meet their particular requirements.
CXML is a type of XML format. Working with data in XML
format is facilitated by numerous freely available libraries written in
various
languages. The table below lists web sites from which routines for
parsing (reading)
and writing XML files can be downloaded, as well as proprietary
software that
includes XML capability.
| Language |
Library |
URL |
| Fortran | XML-Fortran Project | http://xml-fortran.sourceforge.net/ |
| FoX | http://uszla.me.uk/space/software/FoX/ | |
| C++ | Xerxes |
http://xerces.apache.org/xerces-c/ |
| C (interfaces to C++, Perl, Python, Tcl, .NET, Java, C#) | Expat | http://expat.sourceforge.net/ |
| Libxml2 | http://xmlsoft.org/ | |
| Python |
Dave's Page |
http://www.rexx.com/~dkuhlman/#pyxmlfaq |
| Perl |
Xerxes |
http://xerces.apache.org/xerces-p/ |
| Java |
(several) | http://java-source.net/open-source/xml-user-interface-toolkits |
| Xerxes | http://xerces.apache.org/xerces-j/ | |
| Unidata | http://www.unidata.ucar.edu/software/idv/docs/javadoc/ucar/unidata/xml/package-summary.html | |
| IDL | Provided with application |
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| Matlab | Provided with application |
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| Version |
Data model |
Schema |
Last modified |
Revisions |
| 0 | cxml.0.xsd | 23 November 2007 | 1st
draft of CXML file format
specifications released for comment from TIGGE Working Group |
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| 0.1 | Data model (v.0.1) | cxml.0.1.xsd | 4 February 2008 | New data elements added following suggestions from TIGGE WG and colleagues |
| 0.2 | Data model (v.0.2) | cxml.0.2.xsd | 12 May 2008 | See Feedback below |
| 1.0 | Data model (v.1.0) | cxml.1.0.xsd | 4 June 2008 | See Feedback below |
| 1.1 | Data model (v.1.1) | cxml.1.1.xsd | 2 July 2008 | See Feedback below |
| Date |
Individual/Organization
|
Feedback
and suggestions |
Action |
| 25 January 2008 | Tim Hewson, Met Office |
Add elements to represent extratropical cyclone diagnostics as done in the Met Office's cyclone database (click here to see list of diagnostics) | |
| 29 January 2008 | Nick Bower, RPS Metocean Engineers |
In creating a schema and namespace, CXML is not just a standard format for data exchange, but also a way to mix standard with local storage and analysis requirements in a way not possible with previous formats. Users can provide local additional enrichment to CXML based data without corrupting the standard, or even add CXML constructs to existing XML data. | (none) |
| 30 January 2008 | John Knaff, CIRA |
Add elements to represent multiple fixes from different platforms, multiple radii of maximum wind and eye diameters, environmental pressure and tangential winds at fixed radii (say 500km, 1000km). | Done (v.0.2) |
| 2 February 2008 | John Knaff, CIRA |
Include confidence/accuracy information on fix data | Done (v.0.2) |
| 4 February 2008 | Bruce Harper, Systems Engineering Australia |
Include averaging times with wind measurements and estimates | Done (v.0.2) |
| 5 February 2008 | Jeff Kepert, Bureau of Meteorology |
Allow for estimates of precision and/or rounding. Include greater detail on Dvorak parameters | Precision added (v.0.2) |
| 8 February 2008 | Tim Marchok, GFDL |
Break the model resolution into 2 separate identifiers, one for model resolution and one for gridded output data resolution | Done (v.0.2) |
| 12 February 2008 | Ian Shepherd, Bureau of Meteorology |
Tropical cyclone nomenclature is different for different regions and are based on different wind averaging periods. A system can be defined uniquely by its wind speed range and wind averaging period. | Many nomenclatures available for use in CXML |
| 15 February 2008 | Samuel Westrelin, Meteo-France |
This XML format appears to be a good opportunity to get a consensus on the cyclone ID, which varies for different organizations | no consensus yet |
| 18 February 2008 | Justin Ma, HKO |
Provide detailed description of all parameters to avoid mis-interpretation | Draft CXML manual written |
| 21 February 2008 | Chris Sisko, NHC |
The proposal for CXML has merit and if the format specification is clearly and extensively documented, I believe that CXML would be widely adopted and could be provided in real-time for external use. Click here for full comments, and here for replies. | (none) |
| 22 February 2008 | Andrew Burton, Bureau of Meteorology |
Expanded Dvorak parameters | Done (v.0.2) |
| 3 March 2008 | Philippe Caroff, MeteoFrance |
Include all items in WMO Best Track format (2002) | source attribute added to record observations source for various cyclone data |
| 11 May 2008 | Mike Charles, NCEP |
Include information on tracking domain | Optional trackingDomain element added to metadata |
| 4 June 2008 | Mike Charles, NCEP |
Include continent names in subregions to enable extra-tropical cyclone tracking | Continents added to list of allowable subregions (v.1.0) |
| 17 June 2008 | Baudouin Raoult, ECMWF |
basin element differs from the WMO basin abbreviations in the file names. Units should be enforced for consistency. | Basin names modified to be consistent with WMO documents (v.1.1), units specifically enumerated |
| 24 August 2009 | Philippe Caroff, Meteo-France |
Source of data for radius of maximum winds should be described. | (v.1.2) radius element now includes an optional source attribute. |
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