Climatology of Maipo and Rapel river plumes off Central Chile from numerical simulations

Abstract

River-influenced coastal areas are important ecosystems due to the critical influence of river runoff on nutrients and the structure of planktonic and benthic communities. Many studies have focused on the interaction among river runoff, wind, tides and river plume characteristics, and based on observations and modeling results. This study aims to improve our understanding about the circulation and seasonal pattern of river plumes off Central Chile, using climatological simulations in the Regional Ocean Modeling System (ROMS). Results were in reasonable agreement with satellite (MODIS) observations. The plumes exhibit a minimal area cover during summer-fall, with a northwest orientation as result of dominant southwesterly winds and low river discharges. A larger plume area is developed during June–September, as result of higher winter precipitations. The orientation of the plumes during winter is westward, driven by higher river discharges and winds blowing in the southeast direction. An interesting feature reproduced by the model was the trend to coalesce as observed in previous studies using satellite imagery.