133 || Determination of Windspeed at Effective Stack Height for the Gaussian Plume Formula скачать в хорошем качестве

133 || Determination of Windspeed at Effective Stack Height for the Gaussian Plume Formula

Wind speed does change with elevation. As we go higher above the ground, there is less friction with surface features like trees, buildings, and terrain. As a result, wind is slower near the surface due to friction and wind is faster and more uniform at higher elevations. Usually, windspeed is measured with an anemometer that is set up at a height of 10m above the ground. Power law expression is frequently used to establish a relationship between windspeed at the anemometer height and windspeed at the effective stack height less than a few hundred meters above the ground. In order to calculate values of wind profile exponent p, we need to know about the atmospheric stability at the site of the emission. The most commonly used classification of atmospheric stability was developed by Pasquill and Gifford. They defined six classes, named A through F, with A the most unstable class, D neutral atmosphere, and F the most stable class.