The USA Congress last week authorized funding over the next four years for a major upgrade of the USA air traffic control system called NextGen that will be based on advanced GPS technology, rather than the current radar-based approach, with a key element of that system covering weather data, organized around an electronic-business concept called registry and repository.

Anyone who travels to, from, or in the U.S. by air learns quickly the importance of weather in determining the on-time arrival of their flights. Weather accounts for some 70 percent of all flight delays. And even with one National Weather Service in the U.S., weather information is still generated by a multitude of ground-, air-, and space-based sensors providing different types of data, without a common process for aggregating those data.

The role of collecting and assembling weather data in NextGen, and providing forecasts is a system called the Four Dimensional Weather or 4-D Wx Data Cube, a joint initiative of the National Weather Service and Federal Aviation Administration. Weather data will still originate in the same diverse array of sensors, but the 4-D Wx Data Cube will have the job of aggregating those data in a single, consistent, comprehensive way. The new system will also generate up-to-the-minute forecasts, both short- and long-term.

The “4-D” part of the 4-D Wx Data Cube's name refers to the four domains or types of weather information:

1. Air traffic control data
2. Data used by pilots and dispatchers
3. Data existing in both air-traffic and pilot/dispatcher systems
4. All other weather data.

In addition, the system will need to aggregate data from different agencies, organizations, and in some cases businesses. The Department of Defense and NASA, for example, are key stakeholders in this system. And adding to the complexity are data from commercial providers that are often protected by copyrights.

As a result, weather information for different end-users will come from different technologies, originate in different organizations, and have different levels of accessibility due to copyright restrictions. The job of making sense of this complexity falls to an e-business idea called registry and repository that makes it possible to keep using widely different data inputs, but still integrate and aggregate the data for use throughout the air traffic system.

xml-schemas.gif" align="left" alt="XML schemas" title="XML schemas" width="170" hspace="5" vspace="5"/> You can think of repositories and registries in much the same way as a library. The repository stores the actual data items and objects (such as XML schemas) in the same way a library stores physical collections like books and videos. A registry acts as an index to the contents of the repository, much like a card catalog serves as an index to the library's collections.

Because of the high stakes of the air traffic system, the 4-D Wx Data Cube needs an industrial-strength registry and repository for its service-oriented architecture, and its designers chose the Electronic Business XML (ebXML) Registry/Repository specifications. The ebXML specifications are a collection of open-standard documents for developing e-business transactions that include messaging, business processes, collaboration profiles, and business semantics, as well as registry and repository.

The ebXML repositories in the 4-D Wx Data Cube will store the actual data from an array of sources, reflecting the rich complexity of the various contributors. The registry is where the Data Cube will make sense of all that complexity. The Data Cube's registries will store metadata -- data about data -- providing descriptions of those data using common formats.

The common formats for those registry metadata will be Web Services Description Language (WSDL) captured in a Web services profile, and Web Ontology Language (OWL) reflecting the organization of that knowledge in a separate profile. Both of these profiles are already specified in the ebXML registry/repostiory model.

In late January 2012, the members of OASIS -- the organization that manages the ebXML specifications -- approved version 4 of the Registry/Repository specifications, including upgrades sought by the Data Cube designers.

As a result, the NextGen air traffic control system will be able to capture the rich variety of weather data, but serve them up to systems helping air traffic controllers, dispatchers, and flight crews do their jobs.

Alan Kotok is editor and publisher of the Science Business news blog, and author, with David Webber, of ebXML: The New Global Standard for Doing Business on The Internet (New Riders, 2001).