Vargas-Yáñez, M.; Tel, E.; Marcos, M.; Moya, F.; Ballesteros, E.; Alonso, C.; García-Martínez, M.C. Factors Contributing to the Long-Term Sea Level Trends in the Iberian Peninsula and the Balearic and Canary Islands. Geosciences2023, 13, 160.
Vargas-Yáñez, M.; Tel, E.; Marcos, M.; Moya, F.; Ballesteros, E.; Alonso, C.; García-Martínez, M.C. Factors Contributing to the Long-Term Sea Level Trends in the Iberian Peninsula and the Balearic and Canary Islands. Geosciences 2023, 13, 160.
Vargas-Yáñez, M.; Tel, E.; Marcos, M.; Moya, F.; Ballesteros, E.; Alonso, C.; García-Martínez, M.C. Factors Contributing to the Long-Term Sea Level Trends in the Iberian Peninsula and the Balearic and Canary Islands. Geosciences2023, 13, 160.
Vargas-Yáñez, M.; Tel, E.; Marcos, M.; Moya, F.; Ballesteros, E.; Alonso, C.; García-Martínez, M.C. Factors Contributing to the Long-Term Sea Level Trends in the Iberian Peninsula and the Balearic and Canary Islands. Geosciences 2023, 13, 160.
Abstract
We present an attempt to estimate the long-term changes of Relative Sea Level (RSL) and the different factors contributing to such trends on a local and regional scale using a statistical linear model. The time series analysed correspond to 17 tide-gauges grouped in three different areas: the northern and western Atlantic coasts of the Iberian Peninsula, the Canary Islands, and the southern and eastern coasts of the Iberian Peninsula and Balearic Islands. The analysis was performed for two periods: 1948-2019, using tide-gauge data, and 1993-2019, using both tide-gauge and altimetry data for comparison. The trends for the period 1948-2019 ranged between 1.09 0.14 (Canary Islands) and 2.05 0.21 mm/yr, for the northern and western Atlantic Iberian Peninsula. Altimetry data during the period 1993-2019 yielded quite homogeneous results for all the locations and regions, ranging between 2.7 0.4 and 3.0 0.3 mm/yr. On the contrary, the results obtained from tide-gauge data for this recent period showed a large dispersion, very likely due to local effects or even levelling or instrumental errors. Nevertheless, when the results were averaged for each area, the observed trends were comparable to the altimetry results, with values of 2.3 0.8, 2.7 0.5 and 2.8 0.8 mm/yr for the three regions of study. A stepwise forward linear regression has been used to relate the observed RSL variability to the atmospheric forcing and the thermosteric and halosteric components of the sea level. Surprisingly, the thermosteric and halosteric contributions were not significantly correlated to the observed RSL in many cases, and consequently the steric, the total addition of mass, the mass of salt, and the freshwater contributions to the observed sea level trends could not be reliably estimated. This result seems to be the consequence of the scarcity of temperature and salinity data. This hypothesis is confirmed by the exception of L’Estartit tide-gauge. This location is close to a well sampled region. In this case, the atmospheric variables and the thermosteric and halosteric terms explained the 80 % of the observed RSL variance and the contributions of these terms could be estimated. The freshwater contribution for this location was between 1.3 and 1.4 mm/yr, consistent with recent estimations of the contributions of glaciers and Greenland and Antarctica Ice Sheets. These results highlight the importance of monitoring programs and routine sampling for the determination of the different factors contributing to the sea level variability.
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