MODIS Photo:Atmospheric gravity waves between Indonesia and Australia

[Up2Late]

Anyone here know what causes these or can explain this phenomena? Is this common?

Plus, anyone know, are those Coral Atolls or what would you call those little rings? Small Reefs?

<http://rapidfire.sci.gsfc.nasa.gov/gallery/?search=Atmospheric+gravity+waves>



Date: 2005/327 - 11/23
2005327-1123/Australia.A2005327.0230

02 :30 UTC
Atmospheric gravity waves between Indonesia and Australia
Satellite: Terra

[tocqueville]

1. is that a proof of "intelligent falling" ? n/t

[HysteryDiagnosis]

2. Neat..... link.

http://sprg.ssl.berkeley.edu/atmos/gj_science.html

[tridim]

3. I always thought those cloud shapes were caused by turbulence

Does gravity really have that much effect on something as light as clouds? I guess so.

[IndianaGreen]

4. I believe those are waves in the atmosphere itself

I am going to do some reading on atmospheric gravity waves.

Do they always occur near tectonic areas?

[TechBear_Seattle]

5. And the Wikipedia says....

http://en.wikipedia.org/wiki/Gravity_wave

The very short article (Wikipedia is public domain):

For the concept in physics of "waves in the gravity field", see gravitational radiation.

In fluid dynamics, gravity waves are those generated in a fluid medium or on an interface (e.g. the atmosphere or ocean) and having a restoring force of gravity or buoyancy.

When a fluid parcel is displaced on an interface or internally to a region with a different density, gravity restores the parcel toward equilibrium resulting in an oscillation about the equilibrium state. Gravity waves on an air-sea interface are called surface gravity waves or surface waves while internal gravity waves are called internal waves.

Atmosphere dynamics on Earth

Since the fluid is a continuous medium, a traveling disturbance will result. In the earth's atmosphere, gravity waves are important for transferring momentum from the troposphere to the mesosphere. Gravity waves are generated in the troposphere by frontal systems or by airflow over mountains. At first waves propagate through the atmosphere without affecting its mean velocity. But as the waves reach more rarefied air at higher altitudes, their amplitude increases, and nonlinear effects cause the waves to transfer overall momentum.

This process plays a key role in controlling the dynamics of the middle atmosphere.

I've seen this effect while on an air plane. It is breath-taking to fly over the cloud deck and see parallel furrows stretching as far as the eye can see, as if some fairy tale giant had been plowing a field of clouds.

[Orsino]

6. "Gravity" waves seems to be a misnomer.

Every wave with a component parallel to gravity could be called a gravity wave, I guess, but in many media the more important damping force will be tension (e.g, a Slinky stetched sideways). These atmospheric waves seem to be analogous to those in your bathtub; maybe what are portrayed at the Wiki link are standing waves? I gather that "gravity wave" means any wave that is significantly damped by gavitational force.

[Up2Late]

7. Hey, I just cut an pasted exactly what NASA calls them....

...What I find fascinating is the small lines of clouds they cause, due to pressure or compression of the moist air.

Similar to the clouds you see coming off the wing tips of a jet that's making a "High G" turn.