NOAA offers access to new radar data

Java-based application lets scientists quickly view and retrieve information

The National Oceanic and Atmospheric Administration has developed Java-based software that allows public- and private-sector organizations to better browse and view radar data archived at the agency's National Climatic Data Center (NCDC) Web site.

Federal agencies, scientific and academic communities, and possibly emergency management officials will be able to use the interactive viewer and data exporter applications to quickly analyze more information from the Next Generation Weather Radar (Nexrad) system. Some information will be available in real time.

For example, users can overlay Nexrad data with Census Bureau data to analyze who and what was affected by a hurricane.

Steve Ansari, a geographic information system (GIS) programmer for STG who developed the applications for NOAA, said that using this software, he compared precipitation data from last year's Hurricane Charley with information from populations and areas affected by the storm. In ESRI's ArcGIS platform, he compared the Nexrad data with Census 2000 data and displayed on maps and graphs the age and racial distributions of the people affected by 4 inches or more of rain. Emergency officials could similarly use the application to identify vulnerable populations and areas and develop smarter disaster response and recovery efforts, he said.

Officials used a prototype of the applications to analyze the Columbia space shuttle disaster in 2003, said Stephen Del Greco, chief of NCDC's data processing branch in Asheville, N.C. Nexrad data was used to look at the craft's trajectory and debris pattern.

He said such data is useful for gathering information about other phenomena. For example, biologists from two universities are using the applications and radar data to track bird migration, he said.

"The most exciting thing to me is seeing all of these different users basically have their eyes open to the Nexrad data for the first time, particularly users who aren't programmers and maybe biologists or engineers who know GIS and know software and get this data in there," Ansari said. "The mind is the limit for these applications in the future."

Jointly administered by the National Weather Service (NWS), Air Force Weather Agency and Federal Aviation Administration, Nexrad comprises about 159 Weather Surveillance Radar-1988 Doppler sites nationwide and overseas.

Officials store data from the Doppler sites at NCDC and make it available to users for free. The applications support two types of data. Level II is considered raw or base data, and it was hard to disseminate or view before the new applications were created. Level III is meteorological analysis products disseminated by NCDC.

Sophisticated users, such as scientists, use Level II data, Del Greco said. Examples of Level III data users include the Federal Emergency Management Agency for disaster-response analyses, insurance companies for accident investigations and court lawyers for litigation purposes. NWS uses both data types for analysis of major storms, educational purposes and forecasting, he added.

Ansari developed the applications because NWS officials were decommissioning the agency's display mechanism, which was only capable of providing a paper output of data. Users needed to create digital images and animations. STG was already NCDC's mission-support contractor, and about 65 engineers, scientists and computer specialists work for the organization, said Loretta Changery, program manager for STG's NOAA/NCDC program.

The need for such applications was critical because of the amount of archival data stored at the center.

"We're bringing about 80 to 85 terabytes a year right now, and that number, with some of the technologies out in the field, could increase by as much as 1,600 terabytes over the next three or four years that is being ingested at NCDC a year," Del Greco said. "So the archive's quite big. You're looking at an archive of roughly 1,000 terabytes of information."

In March, Ansari said about 470G of Level II data, equivalent to about 100 DVDs, and 40G of Level III data, comprising 1,800 orders, were accessed from the NCDC Web site. He also said source code of both the interactive viewer and data exporter applications is available for anyone who wants to develop custom applications.

"The entire project is open source and leverages off of existing open-source libraries," Ansari said. "There is already development work at the University of Southern Mississippi and North Carolina State University to build upon the project."

Working with data

The Next Generation Weather Radar system's interactive viewer and data exporter application can load archival raw data and product data dating to 1991 from the National Climatic Data Center in Asheville, N.C.

The interactive viewer provides tools for custom data overlays, animations and basic queries. It adds flexibility by incorporating the Web Map Services for custom and unique background maps, such as topographical maps, aerial photography and shaded relief. Data can be saved in multiple image formats.

The data exporter provides a tool to export system data into common formats that can be used with other commercial visualization and geographic information system software packages. It can accommodate data export in vector polygon and raster formats.

— Dibya Sarkar

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