horizontal Momentum
equation

The movement of air (acceleration) inside a typhoon is determined by the sum of four primary forces. This equation is the basic framework for understanding changes in typhoon velocity, direction, and intensity.

4 Forces in equation

PGF

pushes air from high pressure to low pressure. It is the driving force that initiates air movement toward the typhoon's center.

Coriolis Force

An apparent force resulting from Earth's rotation. In the Northern Hemisphere, it deflects moving objects (wind) to the right, which is essential for the rotation of a typhoon.

Gravity

Primarily determines the vertical structure of the typhoon and plays a crucial role in establishing Hydrostatic Balance between the upper and lower atmosphere.

Friction

generated by drag with the Earth's surface. Friction slows down the wind and allows air to spiral inward toward the typhoon's center.

Key Physical Mechanisms

Gradient Wind Balance

A typhoon is a massive low-pressure rotating system. Inside a typhoon, the inward force caused by pressure differences (Pressure-Gradient Force) is in a delicate balance with the outward Centrifugal Force and the Coriolis Force caused by Earth's rotation. As climate change lowers the central pressure, wind speeds must increase to maintain this balance

horizontal Momentum equation