Advancing Atmospheric Science with a State-of-the-art mmWave Phased Array Radar Technology

Atmospheric system science requires high-resolution and high-quality observations of clouds, precipitation, and boundary layer processes for improved understanding and modeling of the Earth's climate. To address this need, a mobile dual-Doppler mmWave fast scanning imaging phased array radar system is proposed. This system combines the unique capabilities of mm-wave radars, such as enhanced sensitivity to small particles, with digital beamforming and fast scanning phased array technology to provide rapid-scanning radar observations of clouds. The proposed system will offer unprecedented science research capabilities, enabling transformative studies of clouds, precipitation, and boundary layer processes. With high-temporal resolution, volumetric imaging at Ka-band, it will provide detailed measurements of convective and stratiform clouds' distributions of vertical velocities and turbulence and the convective boundary layer. Additionally, the system will provide high-quality polarimetric radar products and improved discrimination of ice hydrometeor types. The proposed mobile dual-Doppler mmWave fast scanning imaging phased array radar system will help reduce uncertainties in numerical weather prediction and climate models, leading to more accurate weather forecasting and better-informed policy decisions. Millimeter (mm)-wavelength radars have contributed immensely to the scientific understanding of cloud and precipitation processes, dynamics, and turbulence. Compared to longer wavelength radars used primarily for precipitation studies (S-, C-, and X- bands), existing mmWave radars that rely on parabolic dish antennas have enhanced sensitivity to small particles such as cloud drops and ice crystals. This sensitivity to cloud particles enables microphysical retrievals of ice distribution properties. Analyses of dual-polarization and Doppler spectral data have enabled better discrimination of ice hydrometeor types. Vertically pointing mm-wavelength radars have been used to obtain distributions of vertical velocities and turbulence in convective and stratiform clouds and the convective boundary layer.

To investigate candidate radar technologies to address this need, a trade study of different rapid-scan cloud radars has been undertaken. One result of this effort is a concept called the Ka-band Rapid-scanning Volume Imaging Radar (KaRVIR). This new concept builds upon the emerging use of digital beamforming with weather radars, such as the Atmospheric Imaging Radar (AIR) and C-band Polarimetric Atmospheric Imaging Radar (PAIR), to obtain vertically continuous, rapid-scan radar observations of clouds. KaRVIR will be composed of two polarimetric mobile ground-based Ka-band rapid-scan volumetric imaging radar systems that will enable unprecedented science research capabilities. The combination of unique radar architecture, using mature Ka-band phased array antenna technology with digital beamforming on reception, makes the proposed radar systems feasible and cost-effective.

This paper will discuss the concept of a new development of a dual-polarized Ka-band mobile rapid-scanning volumetric imaging radar system, the first ground-based millimeter-wavelength phased array radar for Earth system science. With unprecedented four-dimensional views from high-temporal resolution, volumetric imaging at Ka-band will enable transformative studies of clouds, precipitation, and boundary layer processes, and unleash innovative applied environmental research to study fires plumes, and insect migration.