Known for hot temperatures, Southern California and the rest of the Southwest United States are undergoing a cold snap that has set records in many areas throughout the region.
Periodogram is the spectrum of a set of time signal usually obtained by fast Fourier transform (FFT). It usually shows frequency as x-axis, and magnit... This page may be out of date.
A periodogram is brute-force. Many different frequencies and candidate periodic signals are evaluated. The statistical significance of each frequency is computed based upon a series of algebraic operations that depend on the particular algorithm used and periodic signal shape assumed. Example: light curve for CoRoT-1: and periodogram for it: