EUR Data Management Group

IWXXM - The "ICAO Weather Exchange Model"

Historical Background

The development of IWXXM, although it was no called like that, started approximately in the year 2004. The main reason was the plan of the WMO (World Meteorological Organization) to replace all alphanumeric code forms by a table driven code form called BUFR (Binary Universal Form for the Representation of meteorological data). Information on BUFR can be found in the WMO Doc. 306, Volume I.2 (Manual on Codes).

Because the WMO governs also meteorological TAC-codes used by ICAO (METAR, SPECI, TAF, AMDAR) the plan was to replace also those. At the EANPG/46 (2004) first conclusions were defined in order to analyse the impact of such a transition. Many concerns were raised during that process from regional planning and implementation groups. The discussion led finally to the decision not to use BUFR but XML (eXtensible Mark-up Language).

In 2009 the WMO completes a pilot project to demonstrate the feasibility of sending OPMET data coded in XML on the AFTN. After that the development of AvXML (Aviation XML) started, involving members from WMO, ICAO as well as Eurocontrol.

In 2010 also the DMG got involved due to a task defined by METG/20 to analyse the implications of the ongoing development.

The term AvXML was replaced by IWXXM (ICAO Weather Exchange Model). The first release candidate (RC) for IWXXM 1.0 was released in December 2012. After receiving back several problem reports, this RC was reworked leading to a second RC, which got issued in May 2013. Finally, in September 2013 IWXXM 1.0 was released. But it only got approved two years later, in June 2015, as IWXXM 1.1. In September 2015 the 17th WMO World Congress agreed this new code form to be part of the WMO 306 (Manual on Codes) as the new Volume I.3, Part D – Representations derived from data models.

Unfortunately the first version of IWXXM still got a lot of issues and therefore a lot of states decided to not implement but wait for the next version. The RC for IWXXM 2.0 was released in April 2016. After review the version IWXXM 2.0, with a number of changes, was released in August 2016. The WMO approved version IWXXM 2.1 was released in March 2017.

To Be Continued...