Map of the Week – Drifting Buoys and Global Sea Surface Temperature | European Marine Observation and Data Network (EMODnet)

News article | 04 August 2023

The sweltering temperatures in July 2023 have broken several significant records ^[¹^]. Heat waves have expanded over the southern half of Europe, North America and Asia, and have caused strong heat stress , posing potential health risks to vulnerable populations ^[²^]. One of the contributing factors to the unusually warm weather is the prolonged duration of high sea surface temperatures (SSTs). SST is the water temperature close to the ocean’s surface. The temperature in the ocean depends on the amount of solar energy that is absorbed at the surface, which is determined by the latitude, weather patterns and sea ice, and on how this energy is distributed throughout the ocean by mixing, tides and currents. The ERA5 data from the Copernicus Climate Change Service (C3S ) reported global average daily SST remained at record values since April until the third week of July ^[¹^]!

Scientists and researchers closely observe the ocean and collect various oceanic parameters in order to monitor the global climate crisis, as well as to study exceptional marine heat wave (MHW ) events, such as North Atlantic Ocean Heatwaves this summer, and their potential consequences on our planet's delicate marine ecosystems. The SST is an important parameter in weather and climate predictions. It is measured by satellite-based instruments and in situ techniques. ^[³^] One of the oceanographic instruments used to automatically collect these temperature measurements are drifting buoys, which are deployed across the ocean. All drifting buoys measure SST, and they are commonly also equipped to measure other variables. As the drifter moves around, guided by ocean currents, measurements of atmospheric pressure, winds, wave height, and salinity can be taken. These observations are relayed by satellite, used immediately to improve forecasts and increase marine safety and are made available through open marine data initiatives like the European Marine Observation and Data Network (EMODnet). Tracking the location of drifters over time also allows scientists to build a profile of ocean currents ^[⁴^].

The rising SST has far-reaching impacts on marine ecosystems and climate patterns. Coral bleaching is a common consequence, as hotter water temperatures put immense stress on coral reefs, leading to coral bleaching events. In July, it was reported that coral reefs along Florida’s coast in the United States have started bleaching. ^[⁵^] Drastic changes in SST can lead to shifts in the distribution and abundance of marine life, impacting entire ecosystems. Warmer SST also poses risk in the disruption of ocean currents and thermohaline circulation patterns. ^[⁶^]. If the thermohaline circulation weakens, the global ‘conveyor belt’ mechanism could be disturbed, leading to alterations in ocean currents, including the Gulf Stream that brings warmth to the United Kingdom and north-west Europe, and would significantly impact the climate system.

With the data collected by satellites, drifting buoys and other advanced technologies, we can better comprehend the scale and implications of the rising SST. Wish to see the data?

Explore the Map of the Week to learn about drifting buoys and click on the drifting buoys symbols to see details including SST and other measured data.
Have a look at the Copernicus Marine Service MyOcean visualisation tool and click onto specific dates and locations to read the data.

Understanding the changes is essential as we strive to mitigate the impact of global warming on the ocean and safeguard the delicate balance of marine life for generations to come.

Access the map

The data in this map are provided by EMODnet.