Mars may look like a quiet, dry world, but its atmosphere is constantly moving. Strong winds, temperature changes, atmospheric waves and huge amounts of dust interact with each other every day. Sometimes, these interactions can produce dust storms that grow from small local events into storms covering large parts of the planet.
Now, scientists have found an important clue that could help explain how these storms develop.
Researchers led by Asumi have directly detected a special atmospheric wave called the K1 Kelvin wave using pressure measurements collected by NASA’s InSight lander. The wave is normally difficult to identify because its frequency is very close to another atmospheric signal caused by Mars’ daily cycle.
The new study shows that the K1 wave becomes much stronger during certain seasons and can become especially powerful during a major Martian dust storm. Scientists also found evidence that the K1 wave can interact with another atmospheric wave, possibly helping dust spread across Mars.
What Is the K1 Wave?
Mars has many atmospheric waves. Some are created by changes in temperature, while others are connected to winds, dust and the planet’s rotation.
The K1 is a type of Kelvin wave. It is called a quasi-diurnal wave because its period is close to one Martian day.
A Martian day, called a sol, is slightly longer than an Earth day. One sol lasts about 24 hours and 39 minutes.
The K1 wave is interesting because it moves through the atmosphere and changes surface pressure. However, detecting it is difficult.
The main problem is that the frequency of K1 is close to the frequency of another strong atmospheric signal called the diurnal tide.
When two signals have almost the same frequency, they can look very similar in measurements. This makes it difficult for scientists to determine which changes come from K1 and which come from the daily atmospheric tide.
For this reason, earlier studies mostly detected K1 indirectly.
The new research takes an important step forward by detecting the K1 signal directly.
InSight Provided the Data
NASA’s InSight lander landed on Mars in 2018 and studied the planet’s interior. But its instruments also collected valuable information about the Martian atmosphere.
One important measurement was surface air pressure.
Scientists can learn a great deal about Mars by studying small changes in pressure over time. These changes can reveal atmospheric tides, waves, winds and even the effects of dust storms.
Asumi and the research team studied more than one Martian year of InSight pressure measurements.
The data included the major MY34 C dust storm, as well as the entire MY35 period.
To separate the different signals hidden in the pressure data, the researchers used a mathematical method called singular spectrum analysis, or SSA.
In simple terms, SSA helps scientists separate a complicated signal into different patterns.
Using this method, the researchers were able to pull out the K1 signal directly from the InSight observations.
K1 Changes During the Martian Year
The strength of the K1 wave was not the same throughout the year.
During the Northern Hemisphere summer, scientists rarely detected a clear K1 signal.
One possible reason is that atmospheric temperatures during this season cause the natural frequency of K1 to become very close to the frequency of the daily atmospheric tide.
When their frequencies become too similar, separating the two signals becomes difficult.
But during Northern Hemisphere spring and autumn, the K1 signal became much clearer.
Its average strength was around 1–2 pascals (Pa).
These pressure changes may appear small, but they are important because they show that the wave is a real and measurable part of Mars’ atmosphere.
The biggest change happened during a major dust storm.
K1 Became Much Stronger During the C34 Dust Storm
During the MY34 C dust storm, the K1 wave became much stronger.
Its amplitude reached approximately 8 Pa.
This was a major increase compared with the normal 1–2 Pa levels seen during spring and autumn.
The strength of K1 also became significant when compared with other atmospheric signals.
During the same storm, the daily S1 signal reached about 39 Pa, while the S2 signal reached approximately 13 Pa.
This means K1 became a surprisingly strong part of the atmosphere during the dust storm.
But the most interesting discovery was not simply the increase in strength.
Scientists found that K1 and another atmospheric signal began moving together.
Two Waves Started Moving in Step
Near the strongest part of the C34 dust storm, the K1 and S1 signals became in phase.
This means their peaks and low points began occurring at nearly the same time.
At around Martian solar longitudes 332°–334°, both signals reached their strongest values.
At the same time, something unexpected happened to the S1 signal.
Its apparent period became shorter.
Normally, the daily atmospheric signal has a period close to one Martian sol, or about 24 Mars hours.
But during this period, its observed period shortened to about 23.5 Mars hours.
After K1 rapidly weakened, the S1 period returned toward approximately 24 Mars hours.
This unusual behavior suggests that the two atmospheric waves were interacting.
Possible Resonance Between the Waves
The researchers believe this could be evidence of a resonance between K1 and an eastward, non-migrating atmospheric tide called DE1.
Resonance happens when waves or oscillations interact at suitable frequencies and can strengthen each other.
A simple example is a swing. If someone pushes a swing at the right time, each push adds energy and the swing moves higher.
A similar process may occur in Mars’ atmosphere.
When K1 and the atmospheric tide become synchronized, their interaction could temporarily make both signals stronger.
This could be especially important during the early stages of a major dust storm.
Dust May Help Start the Process
The researchers suggest that dust itself could help trigger this interaction.
At the beginning of a dust storm, dust may not be spread evenly around Mars. Instead, large amounts of dust can become concentrated in particular regions, especially around the equator.
This uneven distribution changes how sunlight heats the atmosphere.
The resulting temperature differences can create atmospheric pressure changes and winds.
These changes may strengthen the DE1 atmospheric tide while also exciting the K1 wave.
As K1 and DE1 become stronger, their winds can move dust through the atmosphere.
The moving dust then changes atmospheric heating again.
This could create a feedback process:
Dust changes the atmosphere → atmospheric waves become stronger → winds move more dust → the dust storm spreads.
If this process continues, a small regional dust event could gradually become much larger.
Computer Models Support the Discovery
The researchers also compared the InSight observations with computer simulations from the Mars Planetary Climate Model.
The model was tested using dust-storm conditions from MY34 and MY35.
The simulations produced clear K1 signals during the dust storms.
The model also showed that K1 became stronger when it was approximately in phase with S1. After reaching its maximum, the K1 signal decreased quickly.
This behavior was similar to what InSight observed during the C34 storm.
However, there was one important difference.
The computer model did not reproduce the shortening of the S1 period to about 23.5 Mars hours.
Scientists believe the difference may be related to the K1 frequency used by the model.
The model produced a K1 frequency of about 1.02 cycles per sol, while the InSight observations suggested a frequency closer to 1.1 cycles per sol.
Because of this difference, the interaction between the waves occurs differently in the model.
Why This Discovery Matters
Understanding Martian dust storms is important for both science and future exploration.
Dust can reduce sunlight reaching the surface, affect temperatures, change atmospheric circulation and create difficult conditions for spacecraft and surface missions.
Large dust storms can also affect solar-powered landers and rovers by covering their solar panels with dust.
The discovery of K1 gives scientists a new way to study how the Martian atmosphere responds when dust storms begin.
It also shows that atmospheric waves may not simply be a result of dust storms. They may actually help transport dust and influence how storms expand.
The Next Step: Looking at Mars in Three Dimensions
Scientists now want to understand the K1 wave in much greater detail.
Future studies using global Mars climate models and atmospheric datasets could reveal the wave’s structure at different heights and locations.
Observations from across the entire planet would help scientists determine whether K1 travels eastward or westward.
Measurements at different latitudes and altitudes could show how the wave moves through the atmosphere.
Researchers also expect K1 to be particularly strong near the equator. Confirming this would provide another important clue about how the wave is created.
Mars Is More Active Than It Looks
The discovery of the K1 Kelvin wave reveals another hidden layer of Mars’ atmosphere.
Behind the planet’s dry surface is a constantly changing system of dust, winds, temperature and atmospheric waves. During a major dust storm, these elements may interact in ways that can dramatically change the behavior of the atmosphere.
InSight’s pressure measurements have now provided direct evidence of one of these hidden waves.
The findings suggest that K1 may work together with atmospheric tides and moving dust to help Martian dust storms grow and spread.
Mars may appear silent from Earth, but its atmosphere is full of invisible waves—and scientists are only beginning to understand their role.
Reference: Anzu Asumi, Jorge Hernández-Bernal, Kaoru Sato, Aymeric Spiga, "Quasi-diurnal Kelvin Wave Observed in the Atmosphere of Mars by the Pressure Sensor on the InSight Lander", Arxiv, 2026. https://arxiv.org/abs/2608.19892
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