Sea Surface Temperature
Daily sea surface temperatures averaged for the global ocean (top), the Mediterranean Sea (bottom left) and the North Atlantic Ocean (bottom right) between 1991-2020 using ESA’s Climate Change Initiative (green shades), and between 2021-2024 (red shades) + forecast (black) using Mercator Ocean International’s GLO12 analysis for November.
November 2024 was the 2nd warmest November on record (after 2023) at the global level and regionally in the Mediterranean Sea, and in the North Atlantic region with mean temperatures :
- 20.67°C global ocean
- 21.37°C for the Mediterranean Sea
- 23.26°C North Atlantic Ocean
Sea Surface Temperature Anomalies
- Mean sea surface temperature anomalies for November 2024 are close to 1°C in the North Atlantic Caribbean Sea and the Southeast Asia regions (with anomalies of up to 2°C northwest of Australia).
- Anomalies are higher in the Mediterranean Sea and the Gulf of Mexico reaching 2°C.
- The highest anomalies occurred in the Kuroshio region and its extension in the Pacific with patches above 3°C. Note that negative anomalies remain present in the equatorial Eastern Pacific (~ -1°C).
Ongoing marine heatwaves: 30 November 2024
Long warming events may induce important stress on marine ecosystems. In this section are shown the ongoing marine heatwave events on November 30, 2024, and when those have initiated.
- 24.58 % of the global ocean (between 60°S and 60°N) were affected by MHWs on the 30th of November.
- The majority of these MHWs developed recently, with 17.65% of the global Ocean (between 60°S and 60°N) affected by MHWs less than 1 month old and 4.66% by events between 1- and 2-month-old.
Total surface exposed to marine heatwaves (December 2023-November 2024)
- The total surface of MHWs for November 2024 (black line) is stable (~25%).
- This is also true for each category with mostly moderate (yellow line, ~20%) and strong (orange line, ~5%) categories.
- For comparison, in November 2023 (the warmest November on record), MHW extent represented between 30-35% of the global ocean, with a peak in surface of extreme MHWs reaching almost 0.4% of the global ocean (between 60°S and 60°N).
- The maximum surface of marine heatwaves occurs during January and February, the summer season in the southern hemisphere (period of higher marine heatwave occurence), which contains a larger proportion of ocean than its northern counterpart.
European zone (Mediterranean Sea and North Atlantic eastern coast)
- Total MHW surface fluctuated during the month: strong increase during the first half of November (from 13.5% to more than 27%), a decrease to ~18.5%, followed by a second increase to ~24% at the end of the month.
- Despite this peak in extent, MHWs presented mostly moderate categories with a slight variation in strong categories between 1% and 2%.
Global Ocean
European Zone
Total number of marine heatwave days for November 2024
The surface of the ocean impacted by strong, or higher, MHW conditions for at least 1 day was 18.2 %. The impacted regions are mainly the Caribbean Sea and the Southeast Asia region.
The surface of the ocean covered by strong or higher MHW conditions during the entire month is 0.6%. This takes place predominantly in the Caribbean region.
November Statistics
Mean duration, intensity, occupied surface and frequency of marine heatwave events in November months between 1993 and 2024 for the global ocean (left), for the Mediterranean Sea (center) and theNorth Atlantic Ocean (right). Satelite measurements were obtained for the 0.49 m ocean surface layer.
The MHW statistics (MHW duration, intensity, occupied surface and frequency) for November 2024 are compared to November months from previous years (since 1993).
- Global ocean: November 2024 was similar to November 2015, the 3rd most extreme November month (after 1997 and 2023, note that 1997, 2015 and 2023 were “El Niño years”).
- Mediterranean Sea: November 2024 is the 3rd most extreme November after 2022 and 2023.
- North Atlantic Ocean: November 2024 was the 2nd most extreme November month, only November 2023 was more extreme.
About the bulletin
Mercator Ocean International (MOi) publishes a monthly sea surface temperature bulletin reporting on the mean temperature and marine heatwave conditions for the month just passed. It includes:
- Where an MHW is present, the time this event started,
- The timeseries showing the total surface occupied by MHWs globally and for the European region,
- The total number of days of exposure to MHW during the month (including only strong and higher intensity categories).
The results are obtained using the Copernicus Marine Service global analysis system at 1/12° of resolution.
Image citation: European Union, Copernicus Marine Service Data 2024 I © Mercator Ocean
All images in this article can be used freely and should be cited with the information above.
