Sea level variation in the Arctic Ocean since 1979 based on ORAS5 data

Abstract

The Arctic is currently experiencing unprecedented changes across all components of the climate system, primarily driven by global warming. As an important indicator of climate change in the Arctic, sea level reflects variations in both the atmosphere and ocean. This paper analyzes the sea level variation of the Arctic Ocean over the past four decades using ORAS5 data, which is the product of the latest reanalysis-analysis system produced by the European Centre for Medium-Range Weather Forecasts (ECMWF). ORAS5 accurately reproduces the main spatial features of the climatology and temporal evolution of sea surface height (SSH) in the Arctic Ocean, as observed by satellite altimeters, and reveals that seasonal variability is the most significant property of the sea level variation in this region. The seasonal cycle of SSH is closely linked to atmospheric circulation and sea ice formation. The first two dominant modes of the annual-mean SSH in the Arctic Ocean exhibit significant decadal variability. The first mode can be explained by the Ekman transport of wind related to the Arctic Oscillation (AO), which leads to antiphase changes in SSH on the continental shelves and in the deep basins. The second mode shows an antiphase oscillation of SSH between the Eurasian and Canadian Arctic Archipelago (CAA) sides and is driven by the wind anomaly associated with the Arctic dipole anomaly (DA). Due to the decadal variations associated with climate modes, particularly the AO, sea level in the Arctic Ocean has been continuously rising since the mid-1990s or early 2000s, with the most rapid sea level rise occurring in the Beaufort Sea.

Melting sea ice, changing naval geopolitics: The impacts of climate change in the maritime delimitations in the Arctic and the challenges to the UNCLOS

“…The Arctic has been one of the areas in the world most affected by climate change in recent years (Jin et al, 2023;Rantanen et al, 2022;Chylek et al, 2022;McCrystall et al, 2021;Chen et al, 2021;Choudhary et al, 2021;Hogg et al, 2020;Serreze & Meier, 2019; due to the phenomenon of Arctic Amplification (Serreze & Barry, 2011). As the planet warms, the Arctic ecosystem faces intensified impacts, particularly due to accelerated ice cover reduction caused by melting ice and darkening waters.…”

“…Due to its specific geographic characteristics, the Arctic simultaneously maintains a status as a frontier of strategic protection and the "last frontier" of geopolitical and geoeconomic expansion for all the States within the polar territory (Zysk, 2020;McCannon, 2012). This region, isolated for centuries on account of its hostile and extreme environment, has gradually experienced an expansion in both economic and military activities of all regional actors -most intensely Russia, which has sovereignty over 40% of the total Arctic territory-due to the new climatic conditions created by the process of global warming (Jin et al, 2023;Hogg, Fonoberova & Mezić, 2020;Serreze & Meier, 2019;, which has been more intensely felt in this region than in the rest of the planet (Rantanen et al, 2022;Mc-Crystall, et al, 2021;Chen et al, 2021;Choudhary, et al, 2021). All this is owing to a phenomenon scientifically called Arctic Amplification, an ice melting cycle caused by climate change that gets trapped into a feedback loop of warming and melting (Chylek, et al, 2022;Serreze & Barry, 2011).…”

Sea-ice-loss slowdown modulates the sea surface salinification in the Kara–Laptev Seas since the 2008 summer

“…This study uses two sets of monthly SSS data to illustrate the surface salinification: one from the Ocean Reanalysis System 5 (ORAS5) and another from EN4.2.2 objective analyses. ORAS5 data (Copernicus Climate Change Service, Climate Data Store 2021), with its high comparability to satellite and in situ measurements (Hall et al 2021), serves as a reference dataset in recent Arctic climate studies (Nichols and Subrahmanyam 2019, Hall et al 2023, Jin et al 2023, Polyakov et al 2023. Various ocean and ice variables from ORAS5 are used to study the mixed-layer budget and the related mechanisms, including sea-ice concentration, thickness, ice drift velocity, ocean currents, surface wind stress, and sea surface height.…”