"Geostrophic flow" redirects here. For oceanic wind, see Geostrophic current.
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In atmospheric science, geostrophic flow (/ˌdʒiːəˈstrɒfɪk,ˌdʒiːoʊ-,-ˈstroʊ-/[1][2][3]) is the theoretical wind that would result from an exact balance between the Coriolis force and the pressure gradient force. This condition is called geostrophic equilibrium or geostrophic balance (also known as geostrophy). The geostrophic wind is directed parallel to isobars (lines of constant pressure at a given height). This balance seldom holds exactly in nature. The true wind almost always differs from the geostrophic wind due to other forces such as friction from the ground. Thus, the actual wind would equal the geostrophic wind only if there were no friction (e.g. above the atmospheric boundary layer) and the isobars were perfectly straight. Despite this, much of the atmosphere outside the tropics is close to geostrophic flow much of the time and it is a valuable first approximation. Geostrophic flow in air or water is a zero-frequency inertial wave.
This condition is called geostrophic equilibrium or geostrophic balance (also known as geostrophy). The geostrophicwind is directed parallel to isobars...
In atmospheric science, the thermal wind is the vector difference between the geostrophicwind at upper altitudes minus that at lower altitudes in the...
isobars show the direction of geostrophicwinds. Geostrophic flow may be either barotropic or baroclinic. A geostrophic current may also be thought of...
wind on shore during daylight hours. Thermal wind is a meteorological term not referring to an actual wind, but a difference in the geostrophicwind between...
wind component is the difference between actual and geostrophicwind, which is responsible for air "filling up" cyclones over time. The gradient wind...
atmosphere. In the free atmosphere, geostrophicwind relationships should be used. The equation to estimate the mean wind speed ( u z {\displaystyle u_{z}}...
centers is small, and geostrophic flow no longer applies with a useful degree of accuracy. Surface pressure charts supporting gradient-wind conditions Each...
(ageostrophic flow) is the difference between the actual wind or current and the geostrophicwind or geostrophic current. Since geostrophy is an exact balance between...
"free atmosphere", where the wind is approximately geostrophic (parallel to the isobars), while within the PBL the wind is affected by surface drag and...
Over a city or rough terrain, the wind gradient effect could cause a reduction of 40% to 50% of the geostrophicwind speed aloft; while over open water...
further difficulties, because horizontal winds are mostly geostrophic, to a good approximation. Geostrophicwinds merely circulate horizontally, and do not...
drag coefficient increases with increasing wind speed and is greater for shallower waters. The geostrophic drag coefficient is expressed as: C g = τ U...
Isallobaric gradients are important components of the wind as they increase or decrease the geostrophicwind. An isopycnal is a line of constant density. An...
will also be isothermal surfaces, hence (from the thermal wind equation) the geostrophicwind will not vary with depth. Hence, the motions of a rotating...
steepens during frontogenesis, the thermal wind becomes imbalanced. To maintain balance, the geostrophicwind aloft and below adjust, such that regions...
oceans, lakes, and laboratory experiments. Rossby waves, geostrophic currents, and geostrophicwinds are examples of inertial waves. Inertial waves are also...
Adverse pressure gradient Force density Isobar Geopotential height Geostrophicwind Primitive equations Temperature gradient Conner A. Perrine (1967) The...
streamfunction Ψ {\textstyle \Psi } under the quasi-geostrophic assumption. The geostrophicwind field can then be readily deduced from Ψ {\textstyle...
define an approximate geostrophicwind or gradient wind, balanced flows that are parallel to the isobars. Measurements of wind speed and direction at...
parallel to the isobars on an elevation in pressure card. It's called the geostrophicwind. Pressure differences depend, in turn, on the average temperature in...
is the vertically integrated meridional mass transport including the geostrophic interior mass transport and the Ekman mass transport; z ^ {\displaystyle...
the form of upwelling and downwelling, geostrophic flow, and western boundary currents. Friction between wind and the upper surface of a body of water...
thermosphere. Atmospheric tides can be measured as regular fluctuations in wind, temperature, density and pressure. Although atmospheric tides share much...
of the geostrophicwind speed aloft; while over open water or ice, the reduction is between 10% and 30%. In most basins, maximum sustained winds are used...
pressure gradient force (known as geostrophic balance). The true wind almost always differs from the geostrophicwind due to the influence of other forces...
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