Intraseasonal Oscillations and hydroclimate of Northern South America, Central America and Mexico (Part II: Effects on precipitation)

This work is a second part contribution of the effect of intraseasonal oscillations on precipitation over the study region. The index generated for each wave (Part I) allow to classify events like convection inhibiting (dry) and convection favoring (wet) days and correlate with precipitation data from ERA5 and CHIRPS. Results show 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. During wet days, the Tropical Easterly Waves contribute up to 20% of precipitation over Caribbean Sea and eastern Pacific (and western Mexico), while the Kelvin waves accounts for 15% over the tropical eastern Pacific. On the other hand, Mixed Rossby-Gravity waves accounts for 15% of precipitation over the eastern Pacific (10°N - and western Mexico) during wet days and, 12% of precipitation on the Pacific coast of Central America during dry days. Finally, the Madden-Julian Oscillation contributes nearly 15% of precipitation over the Pacific coast of Mexico and Central America during wet days. These findings offer new insights into the spatial and temporal patterns within the region related to these intraseasonal oscillations.