Long-Term Trends and Variability of Water Levels and Tides in Buenos Aires and Mar del Plata, Argentina

SANTAMARIA-AGUILAR, SARA; SCHUERCH, MARK; VAFEIDIS, ATHANASIOS T.; CARRETERO, SILVINA C.

Frontiers in Marine Science

Frontiers Media SA

Año: 2017 vol. 4

We present an analysis of the long-term trends and variability of extreme water and tidallevels and the main tidal constituents using long-term records from two tide gauges inthe wider region of the Rio de la Plata estuary: Buenos Aires (1905?2013) and Mar delPlata (1956?2013). We find significant long-term trends in both tidal levels and the maintidal constituents (M2, S2, K1, O1, and the overtideM4) froma running harmonic analysisin both locations. The tidal range decreased on average 0.63mm y−1, as a result of anincrease of the low water levels and a decrease of the high water levels. We also finda secular decrease in the amplitude of the semi-diurnal constituents and an increaseof the diurnal ones, but of different magnitudes at each location, which suggests thatdifferent processes are producing these changes. In Buenos Aires, an increase of riverdischarge into the estuary seems to reduce the tidal range by hampering the propagationof the tidal wave into the estuary, whereas no influence of river discharge on water andtidal levels can be detected in Mar del Plata. We believe that other factors such asthermohaline changes or the rise of mean sea-level may be responsible for the observedtidal range decrease. Despite the tidal long-term trends, we find no significant trends inthe meteorological component of the tide-gauge records other than an increase in themean sea-level. In addition, we explore teleconnections between the variability of themeteorological component of the tide-gauge records and climate drivers.