The diurnal and semidiurnal rainfall cycles observed over the Brazilian North coastland were studied. A 13 years rainfall dataset derived by the 3B42_V6 algorithm was used. To obtain the amplitude, phase, and variance of each cycle the harmonic analysis was applied to the mean rainfall of 24 hours. Coastlands areas showed cycles modulated by oceanic mechanisms, thus the maximum rainfall was observed at early-morning and nighttime. Inland regions exhibited maximum rainfall at 2100 UTC (17:00 LST) due the local convection mechanism. The highest amplitude of precipitation was observed over the Northeast of the Pará State. The highest rainfall rates were observed during January to April period. The phase of each cycle do not presented significant seasonal variation. The diurnal and semidiurnal harmonics contributed with around 80% to total variance of the daily rainfall. Finally, some future works and applicability of the 3B42_V6 rainfall dataset were suggested.
TRMM; 3B42_V6; harmonic analysis
