{{Unreferenced, date=December 2008
An atmospheric waveguide is an
atmospheric
An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...
flow feature that improves the propagation of certain
atmospheric waves.
The effect arises because wave parameters such as
group velocity
The group velocity of a wave is the velocity with which the overall envelope shape of the wave's amplitudes—known as the ''modulation'' or ''envelope'' of the wave—propagates through space.
For example, if a stone is thrown into the middl ...
or vertical
wavenumber
In the physical sciences, the wavenumber (also wave number or repetency) is the ''spatial frequency'' of a wave, measured in cycles per unit distance (ordinary wavenumber) or radians per unit distance (angular wavenumber). It is analogous to temp ...
depend on
mean flow In fluid dynamics, the fluid flow is often decomposed into a mean flow and deviations from the mean. The averaging can be done either in space or in time, or by ensemble averaging
In machine learning, particularly in the creation of artificial n ...
direction and strength. Thus, for instance,
westerlies
The westerlies, anti-trades, or prevailing westerlies, are prevailing winds from the west toward the east in the middle latitudes between 30 and 60 degrees latitude. They originate from the high-pressure areas in the horse latitudes and trend t ...
might be a good
waveguide
A waveguide is a structure that guides waves, such as electromagnetic waves or sound, with minimal loss of energy by restricting the transmission of energy to one direction. Without the physical constraint of a waveguide, wave intensities de ...
for
east
East or Orient is one of the four cardinal directions or points of the compass. It is the opposite direction from west and is the direction from which the Sun rises on the Earth.
Etymology
As in other languages, the word is formed from the fa ...
ward-traveling waves, but might strongly
dissipate west
West or Occident is one of the four cardinal directions or points of the compass. It is the opposite direction from east and is the direction in which the Sun sets on the Earth.
Etymology
The word "west" is a Germanic word passed into some ...
ward-traveling waves, by increasing or decreasing their vertical wavenumber, respectively. Modification of the waves' group velocity will change their
meridional propagation speed, directing them more
polewards or more
equator
The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can al ...
wards.
Atmosphere