Low-power, short-range, polarimetric, Doppler, X-band weather radar systems are becoming an increasingly popular technology for localized, high space and time resolution weather monitoring and detection, either as a single radar unit or deployed in a network. Some examples of such deployments are the CASA IP1 radar network, the Tokyo X-net, and the Puerto Rico Tropical Weather Test-Bed, where a coordinated deployment of a small number of X-band radar units allows achieving improved coverage results.

Short-range (30 to 50 km) X-band weather radars have several advantages over S-band and C-band weather radars. The higher operating frequency allows the systems to be physically smaller, while offering increased sensitivity thereby reducing the needed transmitter power. This translates into systems that are visually less conspicuous, cheaper to transport, deploy and operate, easier to maintain, and more adaptable to varying terrain. Additionally, the required shorter range allows keeping the radar beam very close to the ground (well below 1 km) and overcome the shadow effect of the Earth’s curvature, while maintaining very high range and azimuth resolution. Maintaining appropriate low-level coverage in areas of high interest has a great impact in improving the resulting data products. This is a fundamental limitation of long-range S-band radar systems, and is of key importance for monitoring all lower troposphere weather phenomena including Quantitative Precipitation Estimation (QPE) applications. Additionally, the differential phase signal (used in QPE applications) at X-band is about three times stronger than of traditional radar frequencies at S-band, making polarimetric measurements of rainfall at X-band even more attractive. The resulting smaller size of X-band systems also enables fast and agile mechanical scanning; allowing the radar to perform arbitrary scanning patterns at high speeds is key in targeting the changing weather scene.

In addition to all the advantages stemming from the use of a higher frequency, there are challenges that need to be addressed to ensure successful radar operation at X-band. Those are the need to maintain a large enough unambiguous Doppler interval, maintain an appropriate level of ground clutter suppression, maintain an appropriate level of second trip echo suppression, and correct the effects of signal attenuation. All these signal-processing requirements have to be maintained in real-time operation of the radar.

With all the technical elements properly addressed, adequate X-band radar units are a very cost-effective way of augmenting the capabilities of existing infrastructure (such as existing S-band systems) or establishing new observation systems. X-band radar systems and X-band radar networks have made an established impact in QPE, now-casting, hydrometeor classification and wind detection, which are key inputs to vital society resources such as weather monitoring and alerts, hydrological models, water management, fleet and traffic management, and broader emergency management.

The radar systems developed by Ridgeline Instruments are built on the rich heritage of Colorado State University as one of the pioneer institutions in the development of X-band radar systems and X-band radar networks, leveraging the latest research in our state of the art radar units. Ridgeline Instruments’ radar systems are designed to be operated remotely, allowing both manual and automated control either as a single radar unit or as part of a coordinated network, and permitting immediate integration with other resources such as multiple-radar control software and network level data processing.