Analyzing Winds for Frequency and Duration

Abstract

Downwash of stack gases near a certain plant occurs when the wind velocity exceeds certain critical values. In order to estimate future occurrences of this phenomenon, it is desirable to know the frequency and duration of those cases in the past in which the critical values have been exceeded. The statistical methods used in selecting and analyzing a typical year’s wind records for purposes of future estimation are discussed. Wind history, valid for the area served by the recording station, is presented in diagrams using a system of probability coordinates. From these data an estimate is made of the frequency and duration of future wind velocities above the critical values. This estimate is valid only for the one plant for which the critical velocities were determined.