Remote Sensing of Weather Hazards Using a Low-Cost and Minimal Infrastructure Off-the-Grid Weather Radar Network

Operational weather radars in the U.S. and other countries in the world are challenged in providing low-altitude observations of rainfall due to the Earth's curvature and their deployment in “sparse” networks spaced hundreds of km apart. Given this limitation, work is underway to explore the feasibility of “dense” networks of small X-band radars. One approach developed by a student team from the U.S. Engineering Research Center for Collaborative and Adaptive Sensing of the Atmosphere (CASA) uses low-cost networks of simple, single-polarization radars that are not dependent on existing infrastructure, operating using solar energy and ad-hoc wireless networks, providing gap-filling data with improved temporal and spatial resolution. This “off-the-grid” (OTG) concept is one that might offer a means to monitor rainfall and provide useful data where it is not feasible or cost-effective to deploy more costly and more accurate radars. This paper describes the OTG concept and design, and presents examples of collected data and respective comparisons from this OTG network with measurements from an S-band NEXRAD radar as well as rainfall data from a set of rain gauges located in Puerto Rico. Results show that CASA OTG radars can provide improved spatial and temporal rainfall estimates with consistent or smaller estimated errors when compared to the S-band radar. End user validation was demonstrated in collaboration with the U.S. National Weather Service during system deployment for the XXI Central American and Caribbean Games celebrated at Mayaguez, Puerto Rico during the Summer of 2010.

I. Introduction

The high acquisition and recurring cost of long-range weather radars and the associated challenges of proper deployment into the infrastructure motivate today's technology of “sparse” weather radar networks. Such networks are typically comprised of physically large, high-power radars spaced hundreds of kilometers apart. The curvature of the earth between these radars results in the radars being blocked from observing rainfall and other weather in low altitudes (below 2 km). This situation applies to the U.S. operational weather radar network and has been documented in the National Research Council [1] report for weather technology beyond the present S-band network.