In this week’s blog, we will cover the basics of wind. This beginner’s guide will explain how wind moves. As we enter June and begin hurricane season, we’ll dive deeper into wind fundamentals in future posts. Have you ever wondered why it’s so windy today or why there’s no wind at all? We’ll explore how wind gets its direction and what causes it to move. Stay tuned for more weather insights.
Well, what is wind?
Wind is the movement of air caused by the uneven heating of the Earth’s surface. The Sun provides energy to the Earth through solar radiation, and because of the Earth’s tilt, the equator receives more sunlight than any other part of the Earth. This causes warm air to rise. Warm air always wants to move to replace the cold air at the poles. Air travels from areas of high pressure to areas of low pressure. In high-pressure areas, molecules are tightly packed, while in low-pressure areas, molecules are more spread out. Just like water is a fluid, our atmosphere is too, flowing all around and above us.
This flow creates what we call atmospheric pressure. Atmospheric pressure is the force exerted on a object due to gravity pulling air towards the ground. The higher you are, the less pressure you feel; at lower altitudes, the atmospheric pressure is greater.
Why does wind curve?
This phenomenon is due to the Coriolis Force. As the Earth rotates, it causes the wind to curve. In the Northern Hemisphere, areas of low pressure, known as cyclones, spin counterclockwise, while high-pressure systems, known as anticyclones, spin clockwise. In the Southern Hemisphere, the pattern is reversed: low-pressure systems rotate clockwise, and high-pressure systems rotate counterclockwise.
There are three main types of wind: global winds, synoptic winds, and mesoscale winds.
Global winds are the prevailing winds that constantly circulate around the Earth. For example, trade winds at the equator blow from east to west, while westerlies, found around 30 degrees latitude, blow from west to east.
Synoptic winds are winds generated by approaching pressure systems or boundary fronts. The pressure gradient force, which is the difference in pressure over a surface, drives these winds. The lines on a weather map, called isobars, indicate areas of equal pressure. Air naturally flows from areas of high pressure to areas of low pressure. When isobars are tightly packed, indicating a steep pressure gradient, strong winds occur.
Mesoscale winds are local winds. For example, a sea breeze occurs on days with low synoptic flow when a strong onshore wind develops suddenly. This happens because land heats up more quickly than the ocean, which has a higher heat capacity. As the land heats up, a low-pressure area develops over it, while a high-pressure area remains over the sea. Air moves from the high-pressure area over the sea to the low-pressure area over the land.