In June 2006, the Office of the Federal Coordinator for Meteorology (OFCM) issued a report titled Federal Research and Development Needs and Priorities for Phased Array Radar, prepared by the Joint Action Group for Phased Array Radar Project (JAG/PARP). Recommendation 3 in the report called for the establishment of an interagency MPAR (multifunction phased array radar) Working Group and the identification of “opportunities for review of program plans and progress by appropriate boards or study committees of the National Academies' National Research Council.” In the intervening two years, the Working Group has, among other activities, pursued investigations at the National Weather Radar Testbed in Norman, Oklahoma and conducted an MPAR Symposium in Norman in September 2007. Other planning activities have proceeded, and a pair of articles outlining the MPAR concept was published in the November 2007 Bulletin of the American Meteorological Society.

In mid-2007 the OFCM, pursuant to the part of Recommendation 3 quoted above, tasked the NRC to carry out an evaluation of the MPAR planning process. The Committee on Evaluation of the Multifunction Phased Array Radar Planning Process was formed to carry out this task. The committee held three meetings in January-April 2008 to gather updated information about the MPAR planning and prepare this report. At the first meeting at the National Academies' Keck Center in Washington, DC, the committee received overview briefings on the MPAR program and the JAG/PARP report. The committee also heard technical briefings on the potential benefits and challenges of a national MPAR system from federal and industrial scientists and engineers. At the second meeting at the National Oceanic and Atmospheric Administration (NOAA) David Skaggs Center in Boulder, Colorado the committee heard additional briefings from prospective agency users of an MPAR system and technical briefings on some of the key hardware issues; they also began intensive work on this report. The third meeting, at the National Weather Center in Norman, Oklahoma was devoted entirely to work on the report.

The committee considered all of the input received at these meetings, as well as a variety of supplementary information about phased array radars and the MPAR program. The committee's review highlighted significant technical and cost issues that need to be resolved to establish the viability of a national MPAR system that can satisfy requirements for aircraft and weather surveillance (and possibly other requirements not yet clearly defined). Prominent among the technical issues is whether phased array radar can provide the quantitative weather measurements (especially of polarimetric variables) needed to support current meteorological applications. Prominent among the cost issues is whether the cost of individual transmit-receive elements can be reduced enough to make array antennas involving many thousands of such elements affordable. In this conference presentation, we provide in more detail the findings and recommendations of the NRC committee