# Why would Earth have stable weather patterns if it stopped spinning and vigorous weather if it had a much faster rotation?

According to https://www.youtube.com/watch?v=nH3bmG-KjvU, Earth would have stable weather patterns after it stopped spinning and according to https://www.youtube.com/watch?v=QHwLopLUrB8, Earth would have vigorous winds if it had an 8 hour rotation period. Would the Coriolis force responsible for vigorous winds?

Weather modeling is crazy complicated so I don't want to make this sound absolute, but Venus virtually doesn't rotate and it has much faster trade winds than Earth. Venus has low surface wind speed but that has to do with the consistent temperature all around it's surface and a very dense almost viscus atmosphere.

You might not get hurricanes with a slow rotation and virtually no Coreolis, but you'd still get weather. The heavy cold air from the night side of the planet would sink and the hot day side of the planet would rise, and you'd get a constant re-balancing of density and a steady wind and likely a lot of rain as the air cooled on the night side, perhaps continuous rain at a certain time during the night (the same process that creates dew but much bigger).

Some good answers on a related question here.

I haven't seen those videos, but in general yes, the rotation of the Earth has a major impact on weather and climate.

The weather and climate are primarily driven by solar radiation that heats up the surface of the Earth and drives global winds and ocean currents. The rotation of the Earth has a major impact in this process, due to the day/night variability of solar radiation, and the Coriolis effect.

For example, all storms, hurricanes, and tornadoes do rotate in the so-called cyclonic direction, that is counterclockwise in the Northern hemisphere. This is a direct consequence of the Coriolis force, that is, the rotation of the Earth. All cyclones are close to a geostrophic balance, which means that the Coriolis force is balanced by a pressure gradient force. That is why storms can last for long periods of time and travel long distances. If the Earth didn't spin, such storms could not exist.

In fact, most phenomena related to weather are affected by the Coriolis effect, for example, the trade winds, jet stream, different air masses, and typical precipitation patterns. None of these would exist if the Earth did not rotate about its axis.

The rotation speed also affects these phenomena. If the rotation rate of the Earth was larger, for example, then storms would have smaller radius but feature stronger winds. If the rotation rate was significantly different (say, twice as fast), it is likely that both the weather and climate of the Earth would be completely different.

Put simply, the coriolis 'force' doesn't change wind speed, but the direction the wind blows. I would say that the winds would become much faster. Consider these facts:

• The speed of the wind is modulated mostly by winds moving winds, friction, and how pressure changes over space.
• Pressure is proportional to temperature and density.

So if the world stopped rotating,

1. One side of the world would become warmer and warmer, as the other side cools. Therefore, the pressure on the side of earth with the sun would rise and the pressure of the dark side would decrease.
2. With the ever growing change in pressure, the winds will increase to try to move the high pressure (warm) air toward the lower pressure (cool) air.
• I think this answer is wrong. From teekarna's answer, the coriolis force probably can affect other forces with a delay which in turn creates violent whether if Earth has an 8 hour rotation period. Also, if all of Earth and everything on it including the atmosphere suddenly stopped, at first there would be very little wind then after the air cools, there would be rapid wind to the night side for a short time then there would be a single convection cell on the night and the night side would be very slowly moving so the pressure difference would become much tinier. Feb 6 '18 at 1:48
• @Timothy If you apply $\vec{v} \cdot \frac{\partial \vec{v}}{\partial t}$ to the Navier-stokes equations, you will find the coriolis parameter vanishes from the equations. Feb 6 '18 at 16:21