Problems with the Current Definitions of the Standard Deviation of Wind Direction

Abstract

Much of the ongoing debate about how to define the standard deviation of wind direction can be attributed to the widespread implementation of a faulty method of defining it in wind-measuring instrumentation in the previous decade. In this paper, the basis of the debate is explained, and the suggestion made that the standard deviation be defined in such a way that it has a useful interpretation. A number of situations are described in which the notion of a circular standard deviation is not appropriate.