An XML format for nowcast data

EXtensible Markup Language (XML) is an internationally recognized format for self-describing text files that are extremely flexible in nature and facilitate data exchange across different information systems including the internet. A new XML format called Weather Markup Language (WxML) is being developed at the Australian Bureau of Meteorology to support the exchange of meteorological data from various sources including nowcasts and the Australian Digital Forecast Database. It is heavily based on the Digital Weather Markup Language (DWML) developed by the US National Weather Service Meteorological Development Laboratory. DWML was chosen as a basis for WxML because of its meteorological focus and its flexibility to accommodate other environmental science applications including climate data and observations.

WxML handles nowcast data that can be spatially represented as geometric shapes, polygons, polylines, and point data. (Other formats such as netCDF were considered more suitable for gridded nowcast data.) The data are treated as individually identified moving or static objects with quantitative and qualitative characteristics. The schema defining the WxML structure currently includes a large variety of characteristics such as location, speed and direction, maximum reflectivity, VIL, hail probability, weather type, and so on. The "extensible" nature of XML makes it extremely easy for users to add new characteristics that are relevant to their particular nowcast application.

WxML will be the standard format for exchanging nowcast data in the WWRP Beijing 2008 Forecast Demonstration Project. Several nowcast systems including NCAR's Thunderstorm Initiation, Tracking, Analysis, and Nowcasting (TITAN), the CAnadian Radar Decision System (CARDS), the Bureau of Meteorology's Thunderstorm Interactive Forecast System (TIFS), and Hong Kong Observatory's Short-range Warnings of Intense Rainstorms in Localized Systems (SWIRLS), have been configured to write nowcast data in WxML format.

Further information on WxML can be found at http://www.bom.gov.au/bmrc/wefor/projects/b08fdp/WxML/.