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Spring 1999

Planes, models, and radar: Unidata's new data activities

A new data source plus some new data sets are giving Unidata's 150-plus university users more resources at the same cost they've been paying: nothing.

In January, Unidata switched to NOAAport, providing data that were previously obtained through the National Weather Service's Family of Services (FOS). NOAAport broadcasts data from weather satellites, ground observing systems, and other sources in near-real time. The change was accomplished through a collaboration among Unidata, the University of Wisconsin Space Science and Engineering Center, and Alden Electronics, which formerly provided the FOS data to Unidata sites. These three organizations and university partners operate NOAAport downlinks and in turn feed the data to other Unidata users. Like all of Unidata's other data offerings except one, the NOAAport data are freely available to colleges and universities for research and education.

The one exception is NIDS, the NEXRAD Information Dissemination System, which comes from a commercial vendor. "NIDS isn't raw data," explains Linda Miller, Unidata external liaison. "It's the type you see on TV. University faculty may use NIDS for a teaching tool, but for research they're crying for Level II data." These are unprocessed radar data containing the radar reflectivity factor, the Doppler velocity, and the spectrum width of the velocity estimate for all points along each radar. (Level I data, containing the raw returned signal, are not being archived for use by the community.)

To meet this user need, Unidata is collaborating with the University of Oklahoma (OU) and several other groups on a project to demonstrate the feasibility of distributing Level II data from National Weather Service (NWS), Federal Aviation Administration, and U.S. Department of Defense radars. Named the Collaborative Radar Acquisition Field Test (CRAFT), the project will use Unidata's LDM (local data manager) software to disseminate data from eight radars in the lower Midwest. CRAFT will involve extensive testing of the technology and evaluation of how Level II data can be used to create high-resolution analyses and forecasts for real-time operational evaluation.

Last September, Miller and Russell Rew from Unidata met with Kelvin Droegemeier (OU), Harry Edmon (University of Washington), and representatives from a number of Oklahoma groups to begin the work on CRAFT. Edmon, the director of the computing facility in his university's Department of Atmospheric Sciences, "has used the LDM to move Level II data around the University of Washington," Miller says. "He's just a dynamite programmer. He made some enhancements in the LDM, and in about three hours he had the system working" (successfully delivering the radar data).

The LDM is fully compatible with the Radar Interface and Data Distribution System (RIDDS)-based ingest system that currently is required to access Level II data from the radars, and it will be fully compatible with the "open systems" standard to be introduced within the next couple of years.

New data sets

Two other new data sources are also available from Unidata this spring. The first, which came on line in December, is the result of a project named CONDUIT (Cooperative Opportunity for NCEP Data Using IDD Technology; IDD is the acronym for Unidata's Internet Data Distribution system). The data are high-resolution, high-frequency results from several forecast models at the National Centers for Environmental Prediction. "This has been a genuine collaborative program as well," says Miller. To get the data out, the U.S. Weather Research Program funded a T1 data line between the NWS's Office of Systems Operation, which is responsible for getting data to the community, and NASA Goddard Space Flight Center. GSFC is serving as the top-level relay node, distributing the data to several additional IDD sites, which in turn relay the data to additional downstream nodes. The IDD mechanism helps alleviate network bottlenecks by eliminating the need for a single site to handle large numbers of recipients.

Data from some of the same models are available through NOAAport, but CONDUIT data are higher resolution and higher frequency. Users of these data are "typically people doing research on the models themselves or doing their own modeling," according to Steven Chiswell, the Unidata meteorologist who organizes the data distribution. "They use these data for boundary conditions."

The other new data set is some 50,000 daily observations collected by commercial aircraft of wind direction and speed and temperature, as well as the aircraft's location and altitude and the time. These data are usually called ACARS, short for Aircraft Communications Addressing and Reporting System, the communications system that transmits the data. Since the measurements often come from places far from radiosonde sites and are collected at all times of the day and night, they can be useful in monitoring the development of various kinds of weather. Aeronautical Data Inc. (ARINC), which operates ACARS, has made the data available to NOAA for model input and forecasting and for research that might benefit the contributing airlines, but the real-time data have not been distributed for other uses until now. Unidata universities will receive them directly from NOAA's Forecast Systems Laboratory, which will make them available via the LDM for research and education.

Miller stresses that these and other new data sets are only made available because of users' needs. The Unidata Users Committee represents the Unidata universities in relaying the needs of the community at large. If you have comments or requests, please e-mail usercomm@unidata.ucar.edu or support@unidata.ucar.edu.

For more information
Unidata home page

Collaborative Radar Acquisition Field Test


ACARS data

To subscribe to the Unidata Newsletter, contact Sally Bates at 303-497-8637 or sally@unidata.ucar.edu.

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Edited by Carol Rasmussen, carolr@ucar.edu
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Last revised: Tue Apr 4 15:10:30 MDT 2000