Trends of Coastal Sea Level Between 1993 and 2015: Imprints of Atmospheric Forcing and Oceanic Chaos
- 7 Downloads
The observation and simulation of the variability of coastal sea level are impacted by various uncertainties, such as measurement errors and sampling biases, unresolved processes, and model and forcing biases. Ocean model simulations suggest that another uncertainty should be taken into account for the attribution of sea-level changes. Global ocean simulations indeed show that resolving mesoscale turbulence (even partly) promotes the emergence of low-frequency (LF) chaotic intrinsic variability (CIV) which causes substantial random fluctuations of sea level up to multiple decades in eddy-active regions of the world ocean. This random LFCIV is superimposed on the atmospherically forced (or simply “forced”) fluctuations, which are directly controlled by the atmospheric variability. We show from a large ensemble of global oceanic hindcasts that this multi-decadal LFCIV leaves a substantial imprint on the long-term trends (1993–2015) of coastal sea level: over 17–20% of the global ocean coastal area, in particular along the coastlines of the northwestern Pacific and Indian Oceans, and around the Gulf of Mexico, random sea-level trends may blur their atmospherically forced counterpart, such that simulated (and potentially observed) coastal sea-level trends cannot be unambiguously attributed to atmospheric or anthropic causes. The steric and manometric sea-level change contributions of these uncertainties are discussed, suggesting that they mostly come from the manometric sea-level trends near the coasts.
KeywordsSea-level trend Coastal ocean Ensemble modeling Intrinsic variability Detection and attribution
This work is a contribution to the OCCIPUT and PIRATE projects. PIRATE (https://sealevel.jpl.nasa.gov/science/ostscienceteam/scientistlinks/scientificinvestigations2017/penduff/) is funded by CNES through the Ocean Surface Topography Science Team (OST-ST). OCCIPUT (https://meom-group.github.io/projects/occiput/) was funded by ANR through contract ANR-13-BS06-0007-01. This work was also supported by the French national program LEFE/INSU and has received funding from the European Union Horizon 2020 research and innovation program under grant agreement No 633211. It is also part of the Copernicus Marine Environment Monitoring Service (CMEMS) GLO-HR project; CMEMS is implemented by Mercator Ocean International in the framework of a delegation agreement with the European Union. We acknowledge that the results of this research have been achieved using the PRACE Research Infrastructure resource CURIE based in France at TGCC. William Llovel was supported by C3S program, “Louis Gentil–Jacques Bourcart” fellowship from the French Académie des Sciences and by the OVALIE project from ESA Living Planet Fellowship fundings. The CCI product is freely available at http://www.esa-sealevel-cci.org/. The model dataset used for this study is freely available on http://zenodo.org (http://doi.org/10.5281/zenodo.1487983). We would like to thank two anonymous reviewers for their constructive comments and helpful suggestions.
- Bessières L, Leroux S, Brankart J-M, Molines J-M, Moine M-P, Bouttier P-A, Penduff T, Terray L, Barnier B, Sérazin G (2017) Development of a probabilistic ocean modelling system based on NEMO 3.5: application at eddying resolution. Geosci Model Dev 10:1091–1106. https://doi.org/10.5194/gmd-10-1091-2017 CrossRefGoogle Scholar
- Church JA, Clark PU, Cazenave A, Gregory JM, Jevrejeva S, Levermann A, Merrifield MA, Milne GA, Nerem RS, Nunn PD, Payne AJ, Pfeffer WT, Stammer D Unnikrishnan AS (2013) Sea level change. In: Stocker TF, Qin D, Plattner G-K, Tignor M, Allen SK, Boschung J, Nauels A, Xia Y, Bex V, Midgley PM (eds) Climate change 2013: the physical science basis. Contribution of working group I to the fifth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge and New YorkGoogle Scholar
- Dussin R, Barnier B (2013) The making of DFS5.1. Drakkar project report, Grenoble, FranceGoogle Scholar
- Griffies SM, Yin J, Durack PJ, Goddard P, Bates SC, Behrens E, Bentsen M, Bi D, Biastoch A, Böning C, Bozec A, Chassignet E, Danabasoglu G, Danilov S, Domingues CM, Drange H, Farneti R, Fernandez E, Greatebatch RJ, Holland DM, Ilicak M, Large WG, Lorbacher K, Lu J, Marsland SJ, Mishra A, Nurser AJG, Salas-Mélia D, Palter JB, Samuels BL, Schröter J, Schwarzkopf FU, Sidorenko D, Treguier A-M, Tseng YH, Tsujino H, Uotila P, Valcke S, Voldoire A, Wang Q, Winton M, Zhang X (2014) An assessment of global and regional sea level for years 1993–2007 in a suite of interannual CORE-II simulations. Ocean Model 78:35–89. https://doi.org/10.1016/j.ocemod.2014.03.004 CrossRefGoogle Scholar
- Legeais J-F, Ablain M, Zawadzki L, Zuo H, Johannessen JA, Scharffenberg MG, Fenoglio-Marc L, Fernandes MJ, Andersen OB, Rudenko S, Cipollini P, Quartly GD, Passaro M, Cazenave A, Benveniste J (2018) An improved and homogeneous altimeter sea level record from the ESA Climate Change Initiative. Earth Syst Sci Data 10:281–301. https://doi.org/10.5194/essd-10-281-2018 CrossRefGoogle Scholar
- Penduff T, Barnier B, Terray L, Bessières L, Sérazin G, Grégorio S, Brankart J-M, Moine M-P, Molines J-M, Brasseur P (2014) Ensembles of eddying ocean simulations for climate. CLIVAR Exchanges, Special Issue on High Resolution Ocean Climate Modelling, 65, vol 19, no 2, July 2014Google Scholar
- Rhein M, Rintoul SR, Aoki S, Campos E, Chambers D, Feely RA, Gulev S, Johnson GC, Josey SA, Kostianoy A et al (2013) Observations: ocean. Chapter 3 in climate change 2013: the physical science basis. In: Stocker TF, Qin D, Plattner G-K, Tignor M, Allen SK, Boschung J, Nauels A, Xia Y, Bex V, Midgley PM (eds) Contribution of working group I to the fifth assessment report of the intergovernmental panel on climate change. Cambridge University Press, CambridgeGoogle Scholar
- Sérazin G, Jaymond A, Leroux S, Penduff T, Bessières L, Llovel W, Barnier B, Molines J-M, Terray L (2017) A global probabilistic study of the ocean heat content low-frequency variability: atmospheric forcing versus oceanic chaos. Geophys Res Lett 44:5580–5589. https://doi.org/10.1002/2017GL073026 CrossRefGoogle Scholar