Final answer:
The troposphere is the portion of the atmosphere closest to Earth's surface affecting the speed of the air due to the Coriolis effect, and is where most weather events occur.
Step-by-step explanation:
A portion of the air in which speed is affected by the earth's surface is called the troposphere. The troposphere is the lowest layer of the atmosphere, extending up to about 12 km above Earth's surface.
This layer contains most of the atmospheric mass and is where weather conditions, such as wind, rain, and storms, occur due to the movement of air masses and the influence of Earth's rotation - known as the Coriolis effect. Atmospheric pressure is also significant here, as it decreases with increasing altitude. The troposphere is critical because it hosts the convection processes that drive our weather, with warm air rising from the Earth's surface and being replaced by cooler air, creating wind and clouds.