Short Wavelength Technology and the Potential for Distributed Networks of Short-Range Radar Systems

We provide an overview of "Distributed Collaborative Adaptive Sensing(DCAS)", which is a new approach to radar sensing of the atmosphere being investigated to overcome coverage limitations inherent in today's use of long-range radar networks for weather surveillance. "Distributed" refers to the use of large numbers of physically small radars, closely spaced to both overcome blockage due to the Earth's curvature and to improve resolution degradation caused by beam spreading in long range systems. In addition to providing the potential for high-resolution sampling throughout the entire troposphere, this distributed concept lends itself to the efficient utilization of low-power electronically-scanned solid-state radars. These radars (once they are developed) are highly reliable, inexpensive, adaptive, and can operate collaboratively, via rapid coordinated targeting of multiple radar beams, based on atmospheric and hydrologic analysis tools (detection, tracking, and predicting algorithms) that diagnose weather conditions in real-time and re-steer radar beams onto specific atmospheric regions for improved detection and forecasting of hazardous weather events. "Collaborative" operation in these networks is envisioned as a means to achieve greater sensitivity, precision, and resolution than is possible with a single beam by coordinating the beam-positions of multiple radars and by processing echoes from multiple beams viewing the same scattering region. "Adaptive" refers to the ability of these radars and their associated computing and communications infrastructure to rapidly reconfigure in response to changing conditions in a manner that optimizes the systems' ability to respond to competing end-user demands. For example, a DCAS radar network might pinpoint tornado locations with extremely high spatial resolution for public warning while simultaneously mapping the horizontal wind field associated with the parent thunderstorm and providing quantitative precipitation estimates for input to distributed hydrological models. The system accomplishes this by continually adjusting both radar parameters (such as pulse-repetition frequency, scan rate/dwell time) and computational functions (such as calculating spectral moments versus calculating full Doppler spectra) during the volume scans of multiple coordinated radars, all in response to changing weather.

In 2003, the National Science Foundation established the Center for Collaborative Adaptive Sensing of the Atmosphere (CASA) as an Engineering Research Center. CASA is a partnership among the University of Massachusetts (lead institution), Colorado State University, University of Oklahoma, University of Puerto Rico, and an extended partnership team from industry, government, and academia configured to create the underlying knowledge, technolgy, and system trade-space for realizing future DCAS systems. This presentation will provide an overview of both the DCAS concept and CASA center, emphasizing the center's strategy and test plan for realizing field-scale prototype versions of future DCAS systems in Oklahoma, Houston, TX, and in Puerto Rico.