3 ms·

for anyone interested, this paper has a nice background on numerical weather prediction http://www.elsevierscitech.com/emails/physics/climate/the_origins_of_co

by kuya 11y ago

for anyone interested, this paper has a nice background on numerical weather prediction http://www.elsevierscitech.com/emails/physics/climate/the_origins_of_computer_weather_prediction.pdf http://www.elsevierscitech.com/emails/physics/climate/the_or...

mediocrejoker 11y ago
I got about 3 pages into this and felt like I was following the discussion until the discussion of an incorrect prediction result that: > In fact, the spurious tendencies are due to an imbalance between the pressure and wind fields resulting in large amplitude high frequency gravity wave oscillations. Since this paper was published within the last 20 years, I can't imagine what they were referring to by 'gravity waves' Do you know what is meant by this statement?
- cos2pi 11y ago
  Gravity waves are waves in a fluid that obtain their restoring force from their buoyancy relative to the surrounding fluid. See [0] for the gory details. Some examples of gravity waves in the atmosphere: [1] [2] [0] http://glossary.ametsoc.org/wiki/Gravity_wave http://glossary.ametsoc.org/wiki/Gravity_wave [1] http://cimss.ssec.wisc.edu/goes/blog/archives/2051 http://cimss.ssec.wisc.edu/goes/blog/archives/2051 [2] https://www.youtube.com/watch?v=yXnkzeCU3bE https://www.youtube.com/watch?v=yXnkzeCU3bE
- Faint 11y ago
  Are you mixing gravity waves and gravitational waves? Gravity waves are any waves in media in which gravity acts as restoring force, like waves in ocean, or waves between layers with different densities in atmosphere, or, AFAIU, whole atmosphere (think of atmosphere as a big shallow pool, with air sloshing around in the pool instead of some liquid). https://en.wikipedia.org/wiki/Gravity_wave https://en.wikipedia.org/wiki/Gravity_wave
- divreg 11y ago
  It's funny that you point this out, since some people in the field of astrophysics are quick to correct others when "gravity waves" are used when they really mean "gravitational waves", and sometimes vice versa. Basically, gravity waves (or g-waves) are a type of perturbation in stratified media where the restoring force on sound waves is buoyancy. The other scenario is where the restoring force is pressure, which are pressure waves (or p-waves). Gravity waves are important in not just planetary atmospheres but stellar media as well, particularly in the outer region of stars. A popular candidate for /gravitational/ wave sources is binary neutron star systems, so the two words aren't interchangeable there since they refer to two very different phenomena!

by kuya 11y ago

mediocrejoker 11y ago

I got about 3 pages into this and felt like I was following the discussion until the discussion of an incorrect prediction result that: > In fact, the spurious tendencies are due to an imbalance between the pressure and wind fields resulting in large amplitude high frequency gravity wave oscillations. Since this paper was published within the last 20 years, I can't imagine what they were referring to by 'gravity waves' Do you know what is meant by this statement?

cos2pi 11y ago
Gravity waves are waves in a fluid that obtain their restoring force from their buoyancy relative to the surrounding fluid. See [0] for the gory details. Some examples of gravity waves in the atmosphere: [1] [2] [0] http://glossary.ametsoc.org/wiki/Gravity_wave http://glossary.ametsoc.org/wiki/Gravity_wave [1] http://cimss.ssec.wisc.edu/goes/blog/archives/2051 http://cimss.ssec.wisc.edu/goes/blog/archives/2051 [2] https://www.youtube.com/watch?v=yXnkzeCU3bE https://www.youtube.com/watch?v=yXnkzeCU3bE
Faint 11y ago
Are you mixing gravity waves and gravitational waves? Gravity waves are any waves in media in which gravity acts as restoring force, like waves in ocean, or waves between layers with different densities in atmosphere, or, AFAIU, whole atmosphere (think of atmosphere as a big shallow pool, with air sloshing around in the pool instead of some liquid). https://en.wikipedia.org/wiki/Gravity_wave https://en.wikipedia.org/wiki/Gravity_wave
divreg 11y ago
It's funny that you point this out, since some people in the field of astrophysics are quick to correct others when "gravity waves" are used when they really mean "gravitational waves", and sometimes vice versa. Basically, gravity waves (or g-waves) are a type of perturbation in stratified media where the restoring force on sound waves is buoyancy. The other scenario is where the restoring force is pressure, which are pressure waves (or p-waves). Gravity waves are important in not just planetary atmospheres but stellar media as well, particularly in the outer region of stars. A popular candidate for /gravitational/ wave sources is binary neutron star systems, so the two words aren't interchangeable there since they refer to two very different phenomena!