Intraseasonal Oscillations and Hydroclimate of Northern South America, Central America and Mexico

Abstract

We examine the influence of intraseasonal variability (10–90 days) on hydroclimatic variables across Northern South America, Central America and Mexico. This variability is driven by planetary and tropical oscillations, including Kelvin waves, Tropical Easterly Waves, Mixed Rossby-Gravity Waves and the Madden–Julian oscillation, all of which display distinct signals in the wavenumber–frequency power spectra. Our findings reveal that intraseasonal variability accounts for 10%–35% of the total variance, depending on the specific location, with Kelvin waves being the largest contributors to the outgoing longwave radiation variance in the study region. Additionally, we observed positive and negative precipitation anomalies across the region associated with each oscillatory process, which can be linked to anomalies in moisture transport and convection within the atmospheric column. The Madden–Julian oscillation contributes 10%–12% of precipitation over continental areas, while Tropical Easterly Waves and Mixed Rossby-Gravity waves account for approximately 40% of the precipitation over the continent. These findings offer new insights into the spatial and temporal patterns within the region. A deeper understanding, diagnosis and prediction of this timescale are crucial for economic sectors such as agriculture, energy generation, risk management and water resources.