Long-term changes in sea-level components in Latin America and the Caribbean

When considering the threat of rising sea-levels, one must take into account not only the changes in the Mean Sea-Level, but also storm surges and changes in extreme events which may also have a bearing on coastal problems. In this study, we combine different components of the total sea-level (astronomical tide, monthly mean sea-level and storm surges) to explain changes detected in the region of Latin America and the Caribbean. Methods based on non-stationary extreme value analysis were applied to storm surge and total sea elevations monthly maxima for the last six decades, while long-term trends in Mean Sea-level were computed from both local regression and a trend-EOF technique. In addition, the relative importance of each factor contributing to the total sea-level is explored by means of defining each statistical distribution. The analysis demonstrates that concerns should be focused on the different components of sea-level in the various areas of the region. For example, changes in the storm surge levels are a key stressor in the Río de la Plata area, while the increase in the extreme total sea-levels in the tropical region and the influence of inter-annual variability on its western coast are the prominent factors. Results show that a clear correspondence between Mean Sea-Level and the Niño3 climate index can be found through a simple regression model, explaining more than 65% of the variance for a representative location on the Peruvian coast.

• Description of the various sea-level components through the reconstruction of Astronomical Tide, Storm Surge and Mean Sea-Level time series
• The relative weight of each sea-level component is analyzed for the region of Latin America and the Caribbean.
• Significant variations in long-term trends in mean sea-level and extremes in storm surge and total sea-level were found.
• Strong correlations with some climatic indices were found for mean sea-level and storm surge.
• The Niño3 index shows a strong linear relationship with mean sea-level in the tropical Pacific coast.