摘要：In this paper, we develop an instrumental index based onhistorical wind direction observations aimed to quantify the moisturetransport from the tropical Pacific to Central and northern South America at a monthly scale. This transport is mainly driven by the so-called “Chocójet”, a low-level westerly jet whose core is located at 5∘N and 80∘W. The Chocó jet is profoundly related to thedynamics of the Intertropical Convergence Zone in the eastern equatorialPacific and it is responsible for up to 30% of the total precipitation inthese areas. We have been able to produce an index for this transportstarting in the 19th century, adding almost a century of data toprevious comparable indices. Our results indicate that the seasonaldistribution of the precipitation in Central America has changed throughout the20th century as a response to the changes in the Chocó jet, decreasing(increasing) its strength in July (September). Additionally, we have foundthat in general, the relationship between the Chocó jet and the El Niño–Southern Oscillation has been remarkably stable throughout the entire 20th century, a finding particularly significant because the stability of this relation is usually the basis of the hydrologic reconstructions in northern South America.
