A violent typhoon that tore across the North Pacific Ocean in April offered a rare look at an unusual spectacle of the natural world, captured in nighttime imagery by a U.S. satellite.
Super Typhoon Sinlaku erupted across the Pacific earlier this year, pounding the Mariana Islands with heavy precipitation and reaching the highest intensity rating used by Japanese monitoring agencies like the Japan Meteorological Agency.
Storms of such intensity are relatively rare occurrences so early in the season, and as the storm increased in intensity while making its way across North Pacific waters, weather monitoring agencies began tracking its movement with satellites.
A Bullseye Over the Pacific
Among the super typhoon’s features as it moved inland was that its effects could be discerned moving not only outward around it, but also upward toward the atmosphere. Because of this, nighttime satellite imagery of the monstrous storm captured something unusual emanating from within the heart of the storm.
The images, recently released by NASA, were obtained by the NOAA-20 satellite’s Visible Infrared Imaging Radiometer Suite (VIIRS) and resemble ripples across the surface of water. That’s because the effect shown in the images is caused by the movement of atmospheric gravity waves as they expand across the storm, radiating outward from its center.
The reason NOAA-20 was specially equipped to capture this phenomenon is that the satellite’s sensor suite is ideal for detecting airglow, a luminous phenomenon that occurs in the atmosphere as atoms and molecules begin emitting excess energy they collect from sunlight during daylight hours.
As the airglow emissions were released into the mesosphere on April 12, 2026, the ripple-like effect became discernible in the satellite imagery, revealing what resembles a massive bullseye over the super typhoon.
Hot Towers Over Super Typhoons
Since airglow involves the release of excess heat, it can be a driver of convection and may at times lead to the formation of tall pillars of cumulonimbus clouds, where towering masses of warm, flat-bottomed cloud can form at relatively low altitudes. The resulting “hot towers” rise from the lowest portions of the atmosphere, known as the troposphere, producing waves as they rise into higher atmospheric regions.
Based on past observations, the formation of gravity waves normally occurs right around the time storms begin to increase in strength. In the case of April’s super typhoon, Sinlaku began intensifying within the 24 hours that preceded the imagery obtained by NOAA-20, progressing from a category 2 all the way up to a category 5 tropical storm.
At the time the imagery was obtained, little moonlight was present, which aided VIIRS in obtaining the imagery, since its day-night band is sensitive to airglow when it occurs in the mesosphere, but also moonlight reflected off clouds. The NOAA-20 images reveal thermal emissions generated by the gravity waves, which continued to be produced over the 24 hours or so that followed as the storm continued to intensify.
Joan Alexander, a senior research scientist at NorthWest Research Associates, says the unique appearance in the imagery actually represents a conical formation, and that the atmospheric gravity waves in the photo are “propagating radially and upward, in a cone-like shape.” Alexander also noted in a recent statement provided to NASA’s Earth Observatory that it was unusual to see an almost perfectly complete array of rings in the airglow above Sinlaku.
More Than Just a Natural Marvel
Scientists like Alexander say there are also practical benefits to observing atmospheric gravity waves, which could aid researchers in monitoring storm development.
“We’d like to use gravity waves to tell us if a storm is intensifying,” she says, noting that it is often difficult to gauge the progress a storm makes as it begins to intensify over the open ocean.
Fortunately, satellites equipped with infrared imaging systems are ideal for spotting gravity waves and other features that could provide crucial information when tracking potentially dangerous tropical storms.
Going beyond just storm tracking, such information could also help to improve weather models, including those related to the stratosphere, where wind patterns and other phenomena can have a significant impact on longer-term forecasts.
Space Weather Implications
Space weather studies may also benefit from the study of atmospheric gravity waves as well. This is because they can often contribute to disturbances in the ionosphere, resulting in similar “rippling” effects in plasma density at higher altitudes. One result of this is plasma “bubbles” which can become concentrated enough that they can even disrupt satellites and impact radio communications.
NorthWest Research Associates senior research scientist Laura Holt says that for scientists who monitor space weather, even a single storm can have major significance when it comes to such atmospheric effects.
“With space weather in particular, a single event such as a tropical cyclone can be very important,” Holt said.
Additional information on atmospheric gravity waves can be found here on NASA’s FAQ and Imagery page, and at the space agency’s Earth Observatory site.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. A longtime reporter on science, defense, and technology with a focus on space and astronomy, he can be reached at micah@thedebrief.org. Follow him on X @MicahHanks, and at micahhanks.com.