In support of two important upcoming enhancements to the NEXRAD system and operational network, an extension to the basedata format has been developed through collaborative efforts by the National Severe Storms Laboratory (NSSL) and NEXRAD tri-agency partners. These two upgrades will include the "super resolution" enhancement and the implementation of dual polarization capability on the production NEXRAD system. Both changes are being prototyped and tested on the NSSL KOUN research radar. The "super resolution" feature will initially double the azimuthal resolution at lower elevations and provide higher resolution reflectivity whereas adding dual polarization capability will add three additional data moments to the existing three. The legacy NEXRAD format specification could not accommodate this additional data without modifications.

In order to facilitate the independent testing of both features and to expedite the transfer of this technology to the production NEXRAD system, a decision was made to formulate an extension to the legacy format to accommodate the increased resolution data and the added moment data. Additionally, it was an opportunity to record additional housekeeping information with the meteorological basedata to facilitate the future real-time and archival value of the data for research and operational use. The advantages of this extra effort to standardize the NEXRAD basedata format for both research and operational use was seen to have a benefit in several related areas. First, the ability to develop, implement, and test new signal processing and algorithm techniques on NSSL radars for potential NEXRAD use, could be accelerated in several areas of faster independent verification and easier transfer of the technology to the operational NEXRAD. Secondly, a common basedata format could be used within NSSL and by other research laboratories to more easily exchange datasets that have NEXRAD potential use, and thereby, again accelerate the transfer of advanced techniques to the NEXRAD production system. And thirdly, the use of the common format along with common access software will lessen development efforts when new radar techniques are implemented and tested.

The first potential application of the format, beyond the use for the two NEXRAD enhancements, is for recording data generated by the phased array radar at the National Weather Radar Testbed being established at NSSL. Because of its non-traditional scanning strategies, additional data fields may be needed to properly and efficiently record the required data. But, as will be described in detail in the full paper, the format allows simple extensions to be added with no or minimal changes to existing data access software. Because the NEXRAD is a baselined configuration managed system, this new format will become a permanent part of the Interface Control Document that formally describes the basedata format. As new fields and parameters are added to the format for research or prototyping use, a research version of the ICD will be maintained in order to track and fully document changes for use by others. Once new techniques targeted for implementation into the NEXRAD baseline system are approved by the NWS Radar Operations Center, changes to the baseline ICD will be submitted to them for comment and tri-agency review before becoming part of the baseline.