When Super Typhoon Sinlaku slammed into the North Pacific in April 2026, it did something most tropical cyclones never do: it sent visible ripples not just across the ocean surface but across the sky itself, all the way into the upper layers of Earth’s atmosphere.
The storm reached “violent typhoon” status, the highest category used by the Japan Meteorological Agency and roughly equivalent to a Category 5 hurricane on the Saffir-Simpson scale, making it one of the few storms in the region to reach such intensity so early in the year. As Sinlaku rapidly strengthened, satellites picked up atmospheric gravitational waves spreading outward from the storm in concentric ring patterns that resemble ripples expanding across a pond after a stone falls into it.The images, captured by instruments aboard NOAA-20 and NASA’s Aqua satellites, have given scientists a rare detailed look at how Earth’s most violent weather can disturb the atmosphere all the way to the edge of space.
What are atmospheric gravitational waves and what is the importance of supercyclone Sinlaku?
Atmospheric gravitational waves are not the same as gravitational waves in the physical sense. They are atmospheric oscillations that occur when air is displaced vertically and then pushed back by buoyancy, the same resting force that makes a wave on water.
When something powerful enough disturbs the lower atmosphere, these oscillations can travel upward through layer after layer of air, carrying the energy from the storm far above the weather system itself.Tropical cyclones generate these waves through the intense release of latent heat near the walls of their eyes. This pushes towering convective clouds known as hot towers that can penetrate the troposphere and pump energy directly into the stratosphere. A peer-reviewed study in Geophysical Research Letters by Hoffman, Wu, and Alexander, drawing on 13.5 years of satellite data from the Atmospheric Infrared Sounder, found statistical evidence that stratospheric gravity wave activity is closely linked to tropical cyclone intensification and that the intensity of those waves can serve as an indicator of how quickly a storm is intensifying.Sinlaku fits this pattern neatly. In the 24 hours before the satellite image was taken, the storm intensified from a Category 2 system to the equivalent of a Category 5, a dramatic, rapidly intensifying event that coincided exactly with the wave signatures detected above it.
How NASA and NOAA satellites captured airglow rings in the mid-atmosphere
The gravitational waves generated by Sinlaku became visible through a phenomenon called airglow, a faint glow produced in the mesosphere, about 80 to 100 kilometers above the Earth’s surface, when atoms and molecules that absorbed solar energy during the day release that energy as light at night.
This pattern is too faint to be seen with the naked eye under normal conditions, but the day-and-night VIIRS (Visible Infrared Imaging Radiometry Suite) range aboard the NOAA-20 satellite is sensitive enough to detect it.The image taken on April 12, 2026 showed almost perfect concentric rings of gravitational waves propagating outward from the center of the storm, a pattern that surprised researchers. According to Joan Alexander, a senior researcher at NorthWest Research Associates, the waves were propagating radially and upward in a cone shape.
What made the observation unusual was that the rings remained almost intact at mesosphere heights.
Normally, winds in the upper atmosphere scatter or weaken gravity waves before they can travel that high. Relatively weak stratospheric winds at the Sinlaku latitude during April 2026 appear to have created an unusually clear path for waves to reach the mesosphere.Filming conditions also played a role. The moon was only 25% illuminated on the night in question, keeping the moonlight reflected from the cloud tops below at low enough levels that the faint airglow signal could be resolved without interference.
The stratospheric signatures were confirmed by NASA’s Aqua satellite
The gravitational wave signal was not limited to the mesosphere. NASA’s Aqua satellite, using the AIRS (Atmospheric Infrared Sounder) instrument, detected thermal emissions from gravitational waves in the stratosphere on April 13, and the same wavy structures appeared again in observations on April 14, confirming that the storm’s influence on the upper atmosphere continued for several days after the initial detection.NASA’s original Earth Observatory report on Sinlaco noted that this type of multi-level atmospheric observation that captures the same gravity wave event simultaneously in both the stratosphere via AIRS and the mesosphere via VIIRS airglow is rare and scientifically valuable because it allows researchers to track how energy moves vertically through the atmosphere from a single storm source.A 2026 study in the Journal of Geophysical Research: Atmosphere Tracking Gravity Waves from Tropical Cyclones Using Multiple Low-Light Satellite Systems found that joint multi-satellite observations can resolve the ongoing evolution of gravity waves from hurricanes in ways that single instrument data cannot, enhancing the value of coordinated NOAA-20 and Aqua observations made during Sinlaco.
Why gravity waves could transform tropical cyclone forecasting
The practical implications of Sinlaku’s gravitational wave signature extend beyond the visual drama of airglow rings. One of the most pressing challenges in tropical cyclone forecasting is monitoring storm intensity over the open ocean, where data from traditional weather stations are sparse or absent. Rapid intensification events in which a storm intensifies significantly within 24 hours are particularly difficult to predict, and are particularly dangerous because they can catch coastal residents by surprise.Alexander noted that gravitational waves could eventually allow researchers to track whether a storm is intensifying, even from remote sensing data alone, by treating the wave signature as an indicator of convective activity near the eyewall. She and her colleagues have proposed that future geostationary satellites equipped with suitable infrared instruments could provide continuous monitoring of gravity waves, giving forecasters a real-time window into storm development over the most isolated parts of the Pacific and Indian Oceans.
