Inter-Annual Variability

The inter-annual variability is a measure of how much a variable changes from one year to the next. Windographer calculates inter-annual variability with the following equation:

where:
	s	is the standard deviation of the annual means
	MoMM	is the mean of monthly means

Note that the standard deviation in the above equation is calculated from the annual means for those years that meet the minimum data coverage requirements you specify in the Options window.