Comparison of Three Frontal Weather Features

Front is a meteorological term that refers to the intersection of cold and warm air. When cold and warm air masses meet, there will be an inclined interface between them, which is called front (front area); The line where the front intersects the ground is called the front. Fronts and fronts are generally called fronts.

Frontal slope

The degree of frontal slope is called frontal slope. The formation and maintenance of front slope is the result of the joint action of geostrophic deflection force and pressure gradient force.

The horizontal pressure gradient force (G) generated between two air masses forces the interface between them to be horizontal.

When the geostrophic force and the pressure gradient force are balanced, the airflow makes geostrophic motion parallel to the front, and then the interface between the cold and warm air masses does not transition to the horizontal direction, showing an inclined state.

temperature pattern

On the weather map, the temperature field in the front area shows that the isotherms are very dense and almost parallel to the front. Because the front is inclined in space, the location of isothermal dense area on each isobaric surface shifts to the cold area side with the increase of height.

Cold front map

Near the front area, because the lower part of the front is a cold air mass and the upper part is a warm air mass, the temperature rises with the height when passing through the front area from bottom to top, which is called front inversion.

pressure field

There are cold and warm air masses with different densities on both sides of the front, so the pressure tendency on both sides of the front is discontinuous. When the isobar crosses the front, a corner is generated, the tip of the corner points to the high-pressure side, and the front falls into the low-pressure groove.

Cold and warm fronts comparison table

wind field

Because the ground front is in a trough of low pressure, according to the gradient wind principle, there should be cyclone shear in the wind field near the front. As shown in the figure, when the cold front is northeast-southwest, the front is mostly southwest wind, and the back is mostly northwest wind, showing anti-cyclone shear.