Applications of the Fast Fourier Transform to Determine the Onset, Duration, and Rainfall Depths of the Los Baños Wet Season

Avelino M. Ramirez¹

ABSTRACT

The onset, duration and the total rainfall of the wet season in the Philippines vary from year to year. The variates however, from natural time series that can be subjected to analysis in both time and frequency domains. Deterministic signals can be extracted from available tree ring data and used to model each of the natural time series. Over the long term, all signals’ frequencies can be determined with certainty, and can be correlated with any forecast variable(s). Analytic difficulties arise for forecasts involving shorter time intervals.

¹Assistant Professor, Agrometeorology and Farm Structures Division (AFSD), Institute of Agricultural Engineering (IAE), College of Engineering and Agro-industrial Technology (CEAT), University of the Philippines Los Baños (UPLB)