For 11 months, a small, unassuming radar sat atop a remote bluff at Cape Grim, Tasmania, quietly listening to the clouds. This was no ordinary instrument—it was CloudCube, a pioneering radar system developed by NASA’s Jet Propulsion Laboratory that could transform how we study Earth’s most elusive weather systems. Perched at the edge of the Southern Ocean, where clean air sweeps in from Antarctica, CloudCube’s G-band prototype gathered unprecedented data on cloud particles, marking a major leap in atmospheric science. The goal? To weigh clouds—not with scales, but with radar.
Clouds remain one of the greatest uncertainties in climate modeling. Their complex microphysics—how tiny droplets and ice crystals form, grow, and fall—affect everything from daily weather forecasts to long-term climate projections. Yet current satellite instruments struggle to capture the full picture, especially in light clouds or during early precipitation stages. CloudCube changes that. By combining Ka-, W-, and G-band radar signals—from 36 to 240 GHz—it simultaneously detects rain, cloud particles, and ice content with a sensitivity never before possible in such a compact system. This is the first time a miniaturized radar has operated across this full spectrum, especially at the high-frequency G-band, which has never been used in space-based observations.
Led by JPL systems engineer Raquel Rodriguez Monje, the CloudCube team engineered a breakthrough in millimeter-wave technology. The instrument generates hundreds of milliwatts at 240 GHz using innovative frequency-multiplication devices—no small feat for a low-power, lightweight system. By minimizing radio frequency components, CloudCube reduces both mass and energy needs, paving the way for more affordable Earth-observing satellites. During its ground deployment at the Department of Energy’s Cloud and Precipitation Experiment at Kennaook (CAPE-K), the G-band channel ran continuously, proving its durability and precision. Later, aboard NASA’s Gulfstream III aircraft, CloudCube captured its first airborne snowfall data during the North American Upstream Feature-Resolving and Tropopause Uncertainty Reconnaissance Experiment, a campaign aimed at improving winter storm predictions.
The implications are profound. With CloudCube, scientists can now probe cloud structure in three dimensions with higher resolution and sensitivity, offering new insights into how clouds influence Earth’s energy balance and water cycle. As climate models demand ever more accurate inputs, instruments like CloudCube could close critical data gaps. The team is now calibrating the airborne data for public release, opening the door for researchers worldwide to explore its potential.
“This is not just an upgrade—it’s a new way of seeing clouds,” said Matt Lebsock, JPL researcher and CloudCube co-investigator. “We’re weighing clouds using these combinations of frequencies in a way we couldn’t before.”