Sea-level Rise and Related Potential Hazards on the Argentine Coast
Keywords:Spectral techniques, storm surges, impacts, coastal erosion
The potential consequences of an eventual acceleration in the rate of sea-level rise on the Argentine coast are considered in the light of the long-term trend in sea-level variation, the impacts that the Argentine coastal areas are undergoing from natural and anthropogenic processes, and the human activities that develop there. Water-level variations were determined from hourly tide height records for Buenos Aires, Mar del Plata, Quequen, and Puerto Madryn. The series used for Buenos Aires (1905 - 1992) and Quequen (1918 - 1981) presented no gaps. For Mar del Plata (1954 - 1992) there were gaps in April and June 1981, November and December 1986, and February and March 1987, while Puerto Madryn (1945 - 1983) showed a gap in May 1982. By suitably completing these gaps the corresponding series of annual levels, calculated as means of monthly mean values, were obtained. Symmetric, low-pass filters with Kaiser-Bessel windows were used to attenuate the contributions from periodic components ranging between 8 and 19 years. The filtered series were subjected to spectral analysis through the Fast Fourier Transform method, recolored in the frequency domain and antitransformed again. The results were used to perform linear regression analyses whose slopes indicated a long-term trend in water-level of + 1.6 ± 0.1 mm/year for Buenos Aires, + 1.4 ± 0.5 mm/year for Mar del Plata, + 1.6 ± 0.2 mm/year for Quequen, and + 3.5 ± 0.1 mm/year for Puerto Madryn. Examples of a rise in water level associated with a storm surge are given to show how this phenomenon affect the Argentine coast. Beach erosion from an accelerated rise in sea-level is quantified for a sector of the sandy shores of the Province of Buenos Aires using the well-known Bruun model. Other likely impacts, particularly on human activities, are also mentioned.