Atmospheric wave

Source: Wikipedia, the free encyclopedia.
Atmospheric waves, associated with a small dust storm of north western Africa on 23 September 2011.

An atmospheric wave is a periodic disturbance in the fields of

solar day (e.g. 24 hours, 12 hours, 8 hours... etc.) are known as atmospheric tides
.

Causes and effects

The mechanism for the forcing of the wave, for example, the generation of the initial or prolonged disturbance in the atmospheric variables, can vary. Generally, waves are either excited by

Northern hemisphere
winter).

Atmospheric waves transport

gravity waves gives rise to the quasi-biennial oscillation
.

In the mathematical description of atmospheric waves,

sinusoidal shape. Spherical harmonics, representing individual Rossby-Haurwitz planetary wave modes, can have any orientation with respect to the axis of rotation of the planet.[1] Remarkably - while the very existence of these planetary wave modes requires the rotation of the planet around its polar axis - the phase velocity of the individual wave modes does not depend on the relative orientation of the spherically harmonic wave mode with respect to the axis of the planet. This can be shown to be a consequence of the underlying (approximate) spherical symmetry of the planet, even though this symmetry is broken by the planet's rotation.[2]

Types of waves

Because the propagation of the wave is fundamentally caused by an imbalance of the

Coriolis effect on horizontal flow is maximal at the poles and zero at the equator
.

There are four different types of waves:

These are longitudinal or compression waves. The sound wave propagates in the atmosphere though a series of compressions and expansions parallel to the direction of propagation.

  • internal
    stratification
    of the atmosphere)
  • inertio-gravity waves (also include a significant Coriolis effect as opposed to "normal" gravity waves)
  • hPa geopotential caused by midlatitude cyclones and anticyclones
    )

At the equator, mixed Rossby-gravity and Kelvin waves can also be observed.

See also

References

  1. ^ Longuet-Higgins, M.S. (1964). "Planetary Waves on a Rotating Sphere". Proc. R. Soc. A. 279: 446–473.
  2. S2CID 239363997
    .

Further reading
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