Scales Of Air Motion

Wind is the motion of air relative to earth's surface. On the macroscale, the movement originates in the unequal distribution of atmospheric temperature and pressure over the earth's surface and is influenced by the earth's rotation. The direction of wind flow is characteristically from high pressure to low, but the Coriolis force deflects the air current out of these expected patterns (see Figure 5.6.2). These phenomena occur on scales of thousands of kilometers and are exemplified by the semipermanent high-and low-pressure areas over oceans and continents.

On the mesoscale and microscale, topographical features critically influence wind flow. Surface variations have an obvious effect on wind velocity and the direction of air flow. Monsoons, sea and land breezes, mountain-valley winds, coastal fogs, windward precipitation systems, and urban heat islands are all examples of the influence of regional and local topography on atmospheric conditions. Mesoscale phenomena occur over hundreds of kilometers; microscale phenomena, over areas less than 10 kilometers.

For an area, the total effect of these circulations establishes the hourly, daily, and seasonal variation in wind speed and direction. The frequency distribution of wind direction indicates the areas toward which pollutants are most frequently transported.

Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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