Wikipedia:Sandbox

DEFINITION
The CMEMS BLKSEA_OMI_tempsal_extreme_var_temp_mean_and_anomaly OMI indicator is based on the computation of the annual 99th percentile of Sea Surface Temperature (SST) from daily mean model data. Two different CMEMS products are used to compute the indicator: The Multy Year Product (MYP) and the Analysis product (NRT).

• Mediterranean sea MYP product: MEDSEA_REANALYSIS_PHYS_006_004
  
• Mediterranean sea NRT product: MEDSEA_ANALYSIS_FORECAST_PHY_006_013
  

Two different indicators constitute the product:

• Map of the 99th mean percentile: It is obtained from the MYP product, the annual 99th percentile is computed for each year of the product. The percentiles are temporally averaged in the whole period (1992-2017).
  
• Anomaly of the 99th percentile in 2018: The 99th percentile of the year 2018 is computed from the NRT product. The anomaly is obtained by subtracting the percentile in 2018 and the mean percentile.
  

CONTEXT
The TEMPSAL SST extreme variability indicator is based on the computation of the 99th percentile (that represent approximately the 1% highest values of SST) from model results, following the same approach applied by Woodworth and Blackman (2004) to extreme sea levels. This method determines changes in the frequency distribution of the measured variables.
The indicator is defined following the steps of other indicators oriented to monitor the variability of extreme events (Pérez Gómez et al., 2016; Pérez Gómez et al.). More details and full scientific evaluation can be found in the CMEMS Ocean State Report 3 (OSR3, Alvarez Fanjul et al., 2019).

CMEMS KEY FINDINGS
The mean Mediterranean SST 99th percentile evaluated in the period 1993-2017 (figure 1, top) presents highest values in the areas of the Gulf of Gabes and in the Eastern part of the basin with values larger than 30oC, while lower values are located close to the Gibraltar strait, in the Gulf of Lion and in the Eastern Aegean Sea. These results are consistent with the ones presented in CMEMS OSR3 for the period 1993-2016. The 2018 99th anomaly map (figure 1, bottom) shows a general positive pattern with maximum values in the North-West Mediterranean area in contradiction with respect to the 2017 anomaly presented in OSR3 probably derived by the different dataset used in the present study (NRT product instead of MYP).

REFERENCES

• Álvarez Fanjul E, Pascual Collar A, Pérez Gómez B, De Alfonso M, García Sotillo M, Staneva J, Clementi E, Grandi A, Zacharioudaki A, Korres G, Ravdas M, Renshaw R, Tinker J, Raudsepp U, Lagemaa P, Maljutenko I, Geyer G, Müller M, Çağlar Yumruktepe V. Sea level, sea surface temperature and SWH extreme percentiles: combined analysis from model results and in situ observations, Section 2.7, p:31. In: Schuckmann K, Le Traon P-Y, Smith N, Pascual A, Djavidnia S, Gattuso J-P, Grégoire M, Nolan G, et al. 2019. Copernicus Marine Service Ocean State Report, Issue 3, Journal of Operational Oceanography, 12:sup1, S1-S123, DOI: 10.1080/1755876X.2019.1633075
  

• 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
  

• Woodworth PL, Blackman DL. 2004. Evidence for systematic changes in extreme high waters since the mid-1970s. Journal of Climate: 1190–1197