Development and validation of a storm surge forecasting/hindcasting modelling system for the extensive Río de la Plata Estuary and its adjacent Continental Shelf

DINÁPOLI, MATÍAS G.; MOREIRA, DIEGO; SIMIONATO, CLAUDIA G.

NATURAL HAZARDS (DORDRECHT)

SPRINGER

Año: 2020

0921-030X

The Río de la Plata (RdP) Estuary is affected by significant surges several times per year.This phenomenon has historically caused catastrophic water-level enlargements of up to4.44 m, threatening and claiming human lives and producing major economic and materialdamages. The negative surges are less frequent, but when they do occur, inhibit theaccess to the principal harbors and waterways and disable the drinking water intakes ofthe Metropolitan Area of Buenos Aires (the Capital City of Argentina) with a populationof more and 16 million people. Recent works suggest that the number and strengthof the surge events have been increasing with time. Nevertheless, a state-of-the-art systemfor the forecast of those events is not available yet. In this work, the implementation of anumerical modelling system for the forecast/hindcast of storm surges and the associatedcurrents in the RdP and the adjacent continental shelf are presented and validated. Thispre-operational system is based on an adaptation of the CROCO community ocean modelto solve the dynamics associated with the surge. The model was implemented using a setof routines written in open-source programming language (Linux and Python) to be cheapand efficient and to ensure an easy future transfer to the services responsible for the alerts.For a better representation of the regional atmospheric dynamics, wind speed and sea-levelpressure used to force the simulations were corrected using direct observations collectedat an oceanographic buoy anchored at the estuary. The model system performance in hindcastmode was quantified by comparison with observations from tidal gauges and currentmeters at several locations of the estuary and the adjacent shelf. Percent errors for waterlevel over the whole estuary and currents in the intermediate and exterior estuary drove toaverage results of 8 and 13%, respectively. The skill scores resulted, on average, of 0.90and 0.80, respectively. The model performance in both hindcast and forecast modes wasevaluated during historical extreme storm surges. Results support the good performanceof the model to simulate even extreme events with average skill scores of 0.97 and 0.92,respectively. Results are encouraging, particularly taking into account the limitations in theatmospheric forcing for the region, where only a relatively small number of direct observationsare assimilated by the reanalysis and forecast models.