What Causes Differing Temperatures & Pressures on Earth?

Earth's Rotation

• The Earth drags the air surrounding it with it as it spins and rotates along its axis. The air in the higher levels of the atmosphere are not as affected by the rotation as they are in the lower levels. Because it isn't being pushed as much, the higher air has higher pressure. The different pressure layers of air mix together and create turbulence. The turbulence generates wind.

Coriolis Force

• The rotation also generates the Coriolis force. This force causes the air to veer to the right instead of moving across the Earth in a straight line. This causes the wind to move in a circle as it travels from the high-pressure levels down to the low-pressure layers. The wind travels in a clockwise direstion along the northern hemisphere and counterclockwise in the southern hemisphere.

Earth's Axis and Revolution

• The tilt of the Earth's axis, combined with the planet's revolution around the sun, affects the temperature along the Earth's surface. As the Earth revolves, certain areas of it receive more heat from the sun than others, making the air warmer. These areas change during each revolution, leading to the change of seasons. This warming effect also affects the air pressure. Warm air rises and is less dense, so warmer climates -- like the Equator -- have lower air pressure than cooler areas -- like the poles.

Time and Surface

• Air temperature changes much more dramatically around land than it does around water. The air warms up more quickly in the daytime above the land, and it cools more quickly at night. This causes the high-pressure air to drop down from above the sea in the daytime and cause breezes, while the same thing occurs over the land at night.

Technology

• Man-made structures can also affect the temperatures. Most structures like streets and buildings are made of steel, concrete and asphalt, which absorb heat rather than relfect it. The buildup of heat from all these structures causes the air and temperature to rise. So it is usually much warmer in urban areas than it is out in rural districts.