Sea-Level Trend at the Southernmost Region of South America

Abstract

Tide gauge data were used to estimate the sea-level trend at the Ushuaia tidal station (548490 S, 688130 W), located at the southernmost city in the world. The Ushuaia tidal station began working in 1951 but was relocated in 1970 approximately 900 m from its original location. Special care was taken in linking both data series to compose a single and reliable sea-level record gathered from 1952 to 2005. The least-square regression line for annual mean sea level (relative to the benchmark) was fitted, and the computed slope that resulted was not significantly different from zero. A low-pass filter was applied to the annual sea-level data series to smooth the constituents of tide longer than 1 year, which could mislead the trend of the mean sea level. The trend of the best fit line computed from the filtered data was 0.2 mm y1, which was not significantly different from zero. Taking into account the Peltier glacial isostatic adjustment prediction, a corrected sea-level trend was estimated in þ1 mm y1 for the Ushuaia tidal station. The sea-level trend was also<br />estimated by processing the altimetry data series gathered at five satellite track crossings located in the adjacent ocean (analyzed period 1992?2011). Resulting sea-level trends computed from altimetry data presented high spatial variability (from 0.9 to þ3.1 mm y1), which is likely associated with the rather short length of the processed data series. The authors of this technical communication foresee that these results will contribute to our knowledge of sea-level change in<br />the Southern Hemisphere, especially southward of 50°S, where long sea-level data series are considerably scarce.