Sea-level trends along freshwater and seawater mixing in the uruguayan Rio de la Plata estuary and Atlantic Ocean coast

Sea level is rising worldwide with local differences due to global and regional drivers. This article analyses yearly freshwater and sea level trends and fluctuations during the mixing of fresh- and sea-water along the Uruguayan coast of the Rio de la Plata River estuary and the Atlantic coast from 1961 to 2014. The global and regional drivers as well as local co-variables are described, classified in nine discrete classes and inter-correlated. Despite the observed increasing trends, local sea level rises (SLR) are not well correlated with global SLR except at the estuarine-ocean boundary (Punta del Este station). Freshwater inflow, which variability often coincides with Oceanic El Niño-La Niña (ONI-ENSO) events, is the first descriptor of sea level fluctuations and outliers all along the coast, particularly at Punta del Este. Local SLR roughly follows the overall global trend with periods of acceleration and stabilization often coinciding with ENSO event

Tendencias recientes de las precipitaciones e impactos asociados con ENSO en la cuenca del Río de la Plata

La evolución temporal de la precipitación anual sobre la cuenca del Río de la Plata (RdP) durante el periodo 1971-2015, evidencia un incremento aproximado de 40 mm y una alta variabilidad interanual, particularmente influenciada por El Niño. Se destacan los años 2002 y 2014 como los más húmedos, superando los 1.700 mm/año, mientras que 1999 y 2008 se destacan como los años más secos, coincidiendo con fases frías del ENSO. La precipitación anual ha aumentado en el promedio de la cuenca (alrededor de 40 mm más en la actualidad que en la década de 1970). Sin embargo, al norte de la cuenca se observa disminución. El índice de intensidad diaria de precipitación (SDII) ha aumentado, aproximadamente 3 mm respecto a los años setenta. Las fuertes tasas de tendencia positiva de lluvia correspondientes a días húmedos para RR>99 percentil (RR99p) son evidentes en la mayor parte de la cuenca. La fuerte tendencia incremental de la precipitación anual parece estar más relacionada con la intensificación de los eventos extremos. Se sugiere que la cuenca se comporta como más húmeda probablemente asociada a eventos de lluvias extremas, que con una mayor frecuencia de días húmedos. Se registraron varias inundaciones, muchas de ellas asociadas a fase cálida del ENSO, que han impactado en la población, debido en gran medida a la vulnerabilidad asociada a la exposición.The evolution of the annual precipitation over the Rio de la Plata basin (RdP) during the period 1971-2015, shows an approximate increase of 40 mm and a high interannual variability, particularly influenced by El Niño. The years 2002 and 2014 are the most humid, exceeding 1,700 mm / year, while 1999 and 2008 stand out as drier years, coinciding with the cold phase of ENSO. Annual precipitation is increased in the basin average (about 40 mm more at present than in the 1970s). However, to the north of the basin there is a decrease. The daily precipitation intensity index (SDII) has increased, approximately 3 mm from the 1970s. The strong positive rainfall rates corresponding to wet days for RR> 99 percentile (RR99p) are evident in most of the basin. The strong incremental trend of annual precipitation seems to be more related to the intensification of extreme events. It is suggested that the basin behaves as wetter probably associated with events of extreme rains, than with a greater frequency of wet days. There were several floods, many associated with El Niño, which have impacted the population, largely due to the vulnerability associated with exposure