Copernicus Marine In Situ TAC - Ocean Monitoring Indicator OMI_EXTREME_SST_MEDSEA_sst_mean_and_anomaly_obs

DEFINITION The OMI_EXTREME_SST_MEDSEA_sst_mean_and_anomaly_obs indicator is based on the computation of the 99th and the 1st percentiles from in situ data (observations). It is computed for the variable sea surface temperature measured by in situ buoys at depths between 0 and 5 meters. The use of percentiles instead of annual maximum and minimum values, makes this extremes study less affected by individual data measurement errors. The percentiles are temporally averaged, and the spatial evolution is displayed, jointly with the anomaly in the target year. This study of extreme variability was first applied to sea level variable (Pérez Gómez et al 2016) and then extended to other essential variables, sea surface temperature and significant wave height (Pérez Gómez et al 2018).  
CONTEXT Sea surface temperature (SST) is one of the essential ocean variables affected by climate change (mean SST trends, SST spatial and interannual variability, and extreme events). In Europe, several studies show warming trends in mean SST for the last years (von Schuckmann et al., 2016; IPCC, 2021, 2022). An exception seems to be the North Atlantic, where, in contrast, anomalous cold conditions have been observed since 2014 (Mulet et al., 2018; Dubois et al. 2018; IPCC 2021, 2022). Extremes may have a stronger direct influence in population dynamics and biodiversity. According to Alexander et al. 2018 the observed warming trend will continue during the 21st Century and this can result in exceptionally large warm extremes. Monitoring the evolution of sea surface temperature extremes is, therefore, crucial. The Mediterranean Sea has showed a constant increase of the SST in the last three decades across the whole basin with more frequent and severe heat waves (Juza et al., 2022). Deep analyses of the variations have displayed a non-uniform rate in space, being the warming trend more evident in the eastern Mediterranean Sea with respect to the western side. This variation rate is also changing in time over the three decades with differences between the seasons (e.g. Pastor et al. 2018; Pisano et al. 2020), being higher in Spring and Summer, which would affect the extreme values.
COPERNICUS MARINE SERVICE KEY FINDINGS The mean 99th percentiles showed in the area present values from 25ºC in Ionian Sea and 26º in the Alboran sea and Gulf of Lion to 27ºC in the East of Iberian Peninsula. The standard deviation ranges from 0.6ºC to 1.2ºC in the Western Mediterranean and is around 2.2ºC in the Ionian Sea. Results for this year show a slight negative anomaly in the Ionian Sea (-1ºC) inside the standard deviation and a clear positive anomaly in the Western Mediterranean Sea reaching +2.2ºC, almost two times the standard deviation in the area.
References:
- Alexander MA, Scott JD, Friedland KD, Mills KE, Nye JA, Pershing AJ, Thomas AC. 2018. Projected sea surface temperatures over the 21st century: Changes in the mean, variability and extremes for large marine ecosystem regions of Northern Oceans. Elem Sci Anth, 6(1), p.9. http://doi.org/10.1525/elementa.191.
- Dubois C, von Schuckmann K, Josey S, Ceschin A. 2018. Changes in the North Atlantic. In: Copernicus Marine Service Ocean State Report, Issue 2, Journal of Operational Oceanography, vol 11, sup1, s66–s70.  https://doi.org/10.1080/1755876X.2018.1489208
- Juza M, Fernández-Mora A and Tintore J. 2022. Sub-Regional Marine Heat Waves in the Mediterranean Sea From Observations: Long-Term Surface Changes, Sub-Surface and Coastal Responses. Front. Mar. Sci. 9:785771. https://doi.org/10.3389/fmars.2022.785771
- IPCC. 2021. Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. V., Masson-Delmotte, P., Zhai, A., Pirani, S.L., Connors, C., Péan, S., Berger, N., Caud, Y., Chen, L., Goldfarb, M.I., Gomis, M., Huang, K., Leitzell, E., Lonnoy, J.B.R., Matthews, T.K., Maycock, T., Waterfield, O., Yelekçi, R., Yu, B. Zhou (eds). Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. www.ipcc.ch/report/ar6/wg1/
- IPCC. 2022. Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. H.-O., Pörtner, D.C., Roberts, M., Tignor, E.S., Poloczanska, K., Mintenbeck, A., Alegría, M., Craig, S., Langsdorf, S., Löschke, V., Möller, A., Okem, B., Rama (eds). Cambridge University Press, Cambridge, UK and New York, NY, USA. www.ipcc.ch/report/ar6/wg2/
- Mulet S, Nardelli BB, Good S, Pisano A, Greiner E, Monier M, Autret E, Axell L, Boberg F, Ciliberti S, Drévillon M, Droghei R, Embury O, Gourrion J, Høyer J, Juza M, Kennedy J, Lemieux-Dudon B, Peneva E, Reid R, Simoncelli S, Storto A, Tinker J, von Schuckmann K, Wakelin SL. 2018. Ocean temperature and salinity. In: Copernicus Marine Service Ocean State Report, Issue 2, Journal of Operational Oceanography, vol 11, sup1, s5–s13. https://doi.org/10.1080/1755876X.2018.1489208
- Pastor F, Valiente JA, Palau JL. 2018. Sea Surface Temperature in the Mediterranean: Trends and Spatial Patterns (1982–2016). Pure Appl. Geophys, 175: 4017. https://doi.org/10.1007/s00024-017-1739-z.
- Pérez-Gómez B, Álvarez-Fanjul E, She J, Pérez-González I, Manzano F. 2016. Extreme sea level events, Section 4.4, p:300. In: Von Schuckmann K, Le Traon PY, Alvarez-Fanjul E, Axell L, Balmaseda M, Breivik LA, Brewin RJW, Bricaud C, Drevillon M, Drillet Y, Dubois C , Embury O, Etienne H, García-Sotillo M, Garric G, Gasparin F, Gutknecht E, Guinehut S, Hernandez F, Juza M, Karlson B, Korres G, Legeais JF, Levier B, Lien VS, Morrow R, Notarstefano G, Parent L, Pascual A, Pérez-Gómez B, Perruche C, Pinardi N, Pisano A, Poulain PM , Pujol IM, Raj RP, Raudsepp U, Roquet H, Samuelsen A, Sathyendranath S, She J, Simoncelli S, Solidoro C, Tinker J, Tintoré J, Viktorsson L, Ablain M, Almroth-Rosell E, Bonaduce A, Clementi E, Cossarini G, Dagneaux Q, Desportes C, Dye S, Fratianni C, Good S, Greiner E, Gourrion J, Hamon M, Holt J, Hyder P, Kennedy J, Manzano-Muñoz F, Melet A, Meyssignac B, Mulet S, Nardelli BB, O’Dea E, Olason E, Paulmier A, Pérez-González I, Reid R, Racault MF, Raitsos DE, Ramos A, Sykes P, Szekely T, Verbrugge N. 2016. The Copernicus Marine Environment Monitoring Service Ocean State Report, Journal of Operational Oceanography. 9 (sup2):  235-320. http://dx.doi.org/10.1080/1755876X.2016.1273446
- Pérez Gómez B, De Alfonso M, Zacharioudaki A, Pérez González I, Álvarez Fanjul E, Müller M, Marcos M, Manzano F, Korres G, Ravdas M, Tamm S. 2018. Sea level, SST and waves: extremes variability. In: Copernicus Marine Service Ocean State Report, Issue 2, Journal of Operational Oceanography, 11:sup1, Chap. 3.1, s79–s88, DOI: https://doi.org/10.1080/1755876X.2018.1489208
- Pisano A, Marullo S, Artale V, Falcini F, Yang C, Leonelli FE, Santoleri R, Nardelli BB. 2020. New Evidence of Mediterranean Climate Change and Variability from Sea Surface Temperature Observations. Remote Sensing 12(132). http://dx.doi.org/10.3390/rs12010132
- von Schuckmann K, Le Traon PY, Alvarez-Fanjul E, Axell L, Balmaseda M, Breivik LA, … Verbrugge N. 2016. The Copernicus Marine Environment Monitoring Service Ocean State Report. Journal of Operational Oceanography, 9(sup2), s235–s320. https://doi.org/10.1080/1755876X.2016.1273446.