① Different meanings
Geostrophic wind is the atmospheric wind field in the horizontal direction of atmospheric movement under the balance of pressure gradient force and Coriolis force (see atmospheric dynamics).
The horizontal distribution of temperature between isobaric surfaces of different layers is uneven, which makes the geostrophic wind change with height, which is called thermal wind (relationship).
Horizontal curve motion of air when pressure gradient force, Coriolis force and inertial centrifugal force are balanced.
② The production principle is different.
Geostrophic wind refers to the horizontal constant-speed linear motion of air in the free atmosphere, which refers to the motion without acceleration and inertial centrifugal force. In this movement, only the horizontal pressure gradient force and geostrophic deflection force play a role. Geostrophic wind is the horizontal movement of air when the horizontal pressure gradient force and geostrophic deflection force are balanced in free atmosphere.
Thermal wind refers to the difference between the two pressure surfaces of geostrophic wind. It is called hot air because the vertical change rate of this geostrophic wind is determined by the horizontal gradient of temperature on the isobaric surface, that is, it is caused by the uneven cold and hot in the horizontal direction. If the temperature does not change horizontally on the isobaric surface, then the geostrophic wind does not change vertically.
Gradient wind is the wind when the pressure gradient force, Coriolis force and inertial centrifugal force are balanced without considering friction.
Extended data
Application of hot air
First of all, it is the main theoretical basis of weather map analysis. Because it relates different levels of geostrophic wind with the horizontal distribution of average temperature, we can understand different levels of geostrophic wind according to the three-dimensional structure of air pressure and temperature.
On the other hand, the relationship of thermal wind can also qualitatively explain some weather phenomena, such as the reason why the westerly winds in the convection circle in the northern hemisphere are superimposed upwards, forming the westerly jet near the tropopause.
When weather analysis is carried out in practical work, temperature advection can be analyzed according to the change of wind with height at a station. When the wind rotates counterclockwise with height, it can be judged that there is cold advection between gas layers, and when the wind rotates clockwise with height, there is warm advection.
Characteristics of gradient wind
In large-scale movement, low pressure is combined with cyclone circulation, and the center of low pressure is cyclone circulation center. The high pressure center is combined with the anticyclone circulation, and the high pressure center is the anticyclone circulation center. When analyzing the position of the high and low pressure centers in the weather map, the circulation model should be considered.
In the northern hemisphere, the gradient wind in low pressure must be parallel to the isobar and rotate counterclockwise around the center of low pressure. The gradient wind in high pressure rotates clockwise around the high pressure center parallel to the isobar. The southern hemisphere is the opposite.
Baidu encyclopedia-the earth turns to the wind.
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