Frequency

From Glossary of Meteorology
(Redirected from Circular frequency)



frequency

  1. The rate of recurrence of any periodic phenomenon, often associated with waves of all kinds.

    Without qualification frequency often means temporal frequency, the rate of recurrence of a time-varying function, but could mean spatial frequency, the rate of recurrence of a space-varying function. Spatial frequency is the reciprocal of the repeat distance (sometimes the wavelength). The dimensions of (temporal) frequency are inverse time. A common unit for frequency is cycle per second, formerly abbreviated cps, but superseded by hertz, abbreviated as Hz. The symbol ν is often used for frequency but f is common in engineering. Period is inverse frequency. Related to frequency, and applied especially to sinusoidally varying quantities, is angular or circular frequency, often denoted by ω = 2πν, with units radians per unit time (e.g., radians per second).

  2. In statistics, the number of times a specified event occurs in a given series of observations; for example, the number of rainy days observed at a particular station during a certain period of time.

    In many types of studies (hydrometeorological, especially) the reciprocal of frequency, the recurrence interval, is used.