The Orinoco Low‐Level Jet during ENSO

This study shows the influence of El Niño–Southern Oscillation (ENSO) over the seasonal and diurnal variability of the Orinoco low-level jet (OLLJ) during the December–January–February (DJF) season. Results show changes in the occurrence and intensity of the OLLJ winds during the phases of ENSO (El Niño and La Niña) in relation to Neutral conditions. During El Niño (La Niña), the OLLJ days decrease (increase) over the mid and exit of the OLLJ corridor. Furthermore, the mean wind vertical profiles (and the intensity of the diurnal cycle) decrease (increase) with values ranging from 5 to 9 m·s−1. We highlight that the OLLJ days decrease (increase) in January (February) during El Niño (La Niña) up to 24% (15%). These changes are modulated by the pressure gradient between the Atlantic subtropical high and the near-equatorial trough regions that decreases (increases) during El Niño (La Niña) and thus induces a decrease (increase) of the OLLJ winds. Moreover, the water vapour flux and precipitation reduce during both phases of ENSO along the OLLJ corridor. This work shows new insights on the OLLJ features during ENSO, which contributes to improving our understanding of the processes that influence the hydro-climatology of northern South America.