Wind is essential to pull a kiteboard through the waves (see photo above), but what exactly is wind, and how is it created?
Did you know? The fastest surface wind ever recorded was 372 km/h, across the summit of Mount Washington during a storm in 1934.
Basically, wind is the movement of air over the earth’s surface that is caused by differences in air pressure. The sun does not heat the earth’s surface evenly. Warmer parts of the earth radiate heat back into the atmosphere and warm the air. This air “pocket” expands and rises as air molecules move away from each other, creating an area of low atmospheric pressure. The surrounding cooler areas have relatively high atmospheric pressure because the air molecules are closer together. Air moves from high pressure to low pressure and that’s called wind. Bigger atmospheric pressure differences result in stronger winds.
Did you know? Southern Canada and the U.S. lie in the primary wind belt known as the “Prevailing Westerlies”, which means that most of our wind and weather moves from west to east.
As an example of wind on a local scale, consider that the sun heats up land faster than water. Therefore, coastal regions enjoy a cooling sea breeze during the day because the warmer, low pressure air over the land rises and the cooler, high pressure air over the ocean moves in. Land cools down faster at night compared to water, so the reversal in relative air pressure causes a land breeze that moves from the land to the ocean.
On a global scale, the earth’s air circulatory system is divided into five zones called the primary wind belts. The direction of these winds is due to the difference in temperature between the equator and the poles, plus the rotation of the earth. Warm air (low pressure) around the equator and cold air (high pressure) at the poles causes movement of really big air masses (or cells). The Earth’s rotation deflects wind in the primary wind belts due to the “Coriolis Effect", which basically means that things (like air) don’t move in straight lines over spinning spheres (like our planet). The primary wind belts circle the globe (parallel to the equator) and contribute to differences in climate at different latitudes.
An accessible overview of wind and weather (Weather Wiz Kids)
For more detailed information about global wind belts:
How Stuff Works: Wind (How Stuff Works) Global Winds (The Weather Doctor) What is wind, what does it do, what good is it, and where can I find it? (CurioCity) Coriolis Effect (Dave Van Domelen, Kansas State University)