Sea level anomaly in the North Atlantic and seas around Europe: Long-term variability and response to North Atlantic teleconnection patterns

Isabel Iglesias; M Nieves Lorenzo; Clara Lázaro; M Joana Fernandes; Luísa Bastos

doi:10.1016/j.scitotenv.2017.07.220

Sea level anomaly in the North Atlantic and seas around Europe: Long-term variability and response to North Atlantic teleconnection patterns

Sci Total Environ. 2017 Dec 31:609:861-874. doi: 10.1016/j.scitotenv.2017.07.220. Epub 2017 Aug 1.

Authors

Isabel Iglesias¹, M Nieves Lorenzo², Clara Lázaro³, M Joana Fernandes⁴, Luísa Bastos⁵

Affiliations

¹ Universidade do Porto, Praça Gomes Teixeira, 4099-002 Porto, Portugal; Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Universidade do Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, S/N, 4450-208 Matosinhos, Portugal. Electronic address: iiglesias@ciimar.up.pt.
² Environmental Physics Laboratory. Facultad de Ciencias. Universidade de Vigo, 32004 Ourense, Spain. Electronic address: nlorenzo@uvigo.es.
³ Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Universidade do Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, S/N, 4450-208 Matosinhos, Portugal; Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal. Electronic address: clazaro@fc.up.pt.
⁴ Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Universidade do Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, S/N, 4450-208 Matosinhos, Portugal; Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal. Electronic address: mjfernan@fc.up.pt.
⁵ Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Universidade do Porto, Terminal de Cruzeiros do Porto de Leixões, Avenida General Norton de Matos, S/N, 4450-208 Matosinhos, Portugal; Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal. Electronic address: lcbastos@fc.up.pt.

PMID: 28783913
DOI: 10.1016/j.scitotenv.2017.07.220

Abstract

Sea level anomaly (SLA), provided globally by satellite altimetry, is considered a valuable proxy for detecting long-term changes of the global ocean, as well as short-term and annual variations. In this manuscript, monthly sea level anomaly grids for the period 1993-2013 are used to characterise the North Atlantic Ocean variability at inter-annual timescales and its response to the North Atlantic main patterns of atmospheric circulation variability (North Atlantic Oscillation, Eastern Atlantic, Eastern Atlantic/Western Russia, Scandinavian and Polar/Eurasia) and main driven factors as sea level pressure, sea surface temperature and wind fields. SLA variability and long-term trends are analysed for the North Atlantic Ocean and several sub-regions (North, Baltic and Mediterranean and Black seas, Bay of Biscay extended to the west coast of the Iberian Peninsula, and the northern North Atlantic Ocean), depicting the SLA fluctuations at basin and sub-basin scales, aiming at representing the regions of maximum sea level variability. A significant correlation between SLA and the different phases of the teleconnection patterns due to the generated winds, sea level pressure and sea surface temperature anomalies, with a strong variability on temporal and spatial scales, has been identified. Long-term analysis reveals the existence of non-stationary inter-annual SLA fluctuations in terms of the temporal scale. Spectral density analysis has shown the existence of long-period signals in the SLA inter-annual component, with periods of ~10, 5, 4 and 2years, depending on the analysed sub-region. Also, a non-uniform increase in sea level since 1993 is identified for all sub-regions, with trend values between 2.05mm/year, for the Bay of Biscay region, and 3.98mm/year for the Baltic Sea (no GIA correction considered). The obtained results demonstrated a strong link between the atmospheric patterns and SLA, as well as strong long-period fluctuations of this variable in spatial and temporal scales.

Keywords: North Atlantic Ocean; Sea level pressure; Sea level variability; Sea surface temperature anomaly; Teleconnection patterns; Wind.