NASA's CloudCube Miniaturized Radar Studies Clouds and Precipitation

A compact, multifrequency radar developed by the National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory (JPL) will enhance data collection on cloud systems. This instrument, named CloudCube, uses three radar signals to probe the atmosphere. These signals span 36 to 240 gigahertz (GHz).

CloudCube's design allows for optimized sensitivity to various sizes of water droplets and ice particles. It transmits and receives Ka-band, W-band, and G-band signals. This makes it the first compact radar system to simultaneously probe meteorological targets across wavelengths of approximately one to ten millimeters.

Researchers can combine data from the three signals to better understand precipitation initiation and evolution. The instrument also provides insights into cloud microphysics and radiative properties. Raquel Rodriguez Monje, a systems engineer at JPL and CloudCube's principal investigator, noted the instrument's low power and mass. This design facilitates cost-efficient atmospheric observation missions.

Each signal band observes different aspects of cloud physics. Ka-band radar is suitable for precipitation profiles. W-band radar measures cloud particles that lead to precipitation. G-band radar, a new capability for space-based instruments, measures ice and liquid water content in very light clouds. CloudCube integrates three radar modules into a single compact system using innovations in millimeter-wave hardware.

One innovation involves specialized components for G-band power transmission from a low-power instrument. CloudCube generates hundreds of milliwatts at 240 GHz by combining outputs from multiple high-efficiency frequency-multiplication devices. The instrument's design minimizes radio frequency components, reducing mass and power consumption. This could lower costs for future Earth-observing orbital instruments.

CloudCube has undergone field testing. A ground-based prototype of its G-band channel operated for eleven months during the Department of Energy's Cloud and Precipitation Experiment at Kennaook (CAPE-K) campaign. It also participated in the Eastern Pacific Cloud Aerosol Precipitation Experiment. Most recently, CloudCube successfully collected airborne snowfall observations from NASA's Gulfstream III aircraft during the North American Upstream Feature-Resolving and Tropopause Uncertainty Reconnaissance Experiment campaign.