NASA's Juno Catches 3 Waves of Jupiter's Polar Cyclones

This composite shows views of Jupiter's northern polar cyclones in three different wavelengths of light – microwave, visible, and ultraviolet – as captured by NASA's Juno mission. These differing perspectives allowed Juno scientists to deduce that all Jovian polar cyclones are not created equal.

The infrared image, on the far right, was derived from data collected by the spacecraft's Jovian Infrared Auroral Mapper (JIRAM) instrument. The composite image at center was collected by the JunoCam visible-light imager. Though taken with separate instruments that record different wavelengths of light, both images depict Jupiter's northern polar storms as well defined and of similar size.

The data on the left, collected by Juno's Microwave Radiometer (MWR), shows the polar storms in another light. MWR enables Juno to see deep into Jupiter by recording the planet's microwave emissions. In the MWR graphic, the polar storms at the 4 and 6 o'clock positions have bright microwave signatures, indicating they extend well beneath the cloud tops, at least 62 miles (100 kilometers) below. The size of those two storms is comparable to what's found in the visible light and infrared light images, but the other storms, as seen through MWR, have a notably reduced emissions intensity.

Another disparity in the MWR graphic versus visible light and infrared can be seen in how the central cyclone is depicted by the data. In the infrared and visible light images, the central cyclone is evident; with MWR data, it all but disappears. This disparity indicates that the central cyclone's subsurface structure must be very different from the surrounding storms.

JIRAM "sees" in infrared light not visible to the human eye. It captures the infrared glow from the heat of Jupiter's upper atmosphere, probing the top of the weather layer, and gaps in the clouds allow glimpses as deep as 30 to 45 miles (50 to 70 kilometers) below Jupiter's cloud tops.

JunoCam's visible light images catch reflected sunlight, with a view that is very similar to what a human eye would see if a person could ride along with Juno. JunoCam's raw images are available for the public to peruse and process into image products at https://missionjuno.swri.edu/junocam/processing.

Like JIRAM, the MWR instrument records the glow of Jupiter's atmosphere, but the brightness results from the temperature at depths below anything achievable with previous spacecraft or Earth-based observations. The MWR's six radio channels peer progressively deeper below the visible cloud tops, with a range from the top of the clouds (for the highest frequency channel) to 200 miles (320 kilometers) or more below (for the lowest frequency channel).

More information about Juno is at https://www.nasa.gov/juno and https://missionjuno.swri.edu. For more about this finding and other science results, see https://www.missionjuno.swri.edu/science-findings.