Ocean

The ocean plays a vital role in the global climate system, and as a result human activity is both affected by and contributes to changes to the ocean. Marine ecosystems are crucial for maintaining biodiversity, accounting for 90% of the habitable space on the planet. They also produce over 50% of the planet’s oxygen and provide a source of food and medicine. As a consequence of its capacity to act as a carbon sink, ocean acidification is rapidly changing marine environments. As global temperatures increase, sea levels are rising, affecting the livelihoods of coastal communities. Understanding the state of the ocean requires frequent, global observations of physical, biological and chemical variables. Very small changes in these variables can have significant impacts on ocean systems, so characterising the ocean presents many significant measurement challenges.


Our ocean section covers the metrological contribution to support in situ measurements of Global Climate Observing System (GCOS) Oceanic Essential Climate Variables (ECVs) along with the broader Essential Ocean Variables defined by the Global Ocean Observing System. These include physical (e.g. temperature, salinity, currents, ice), biogeochemical (e.g. dissolved gases and nutrients, acidification, particulate matter and tracers) and biological (e.g. phytoplankton, ocean sound) variables. Alongside climate applications, the Ocean Observation section reflects the broader variety of economic, societal, and environmental perspectives relating to the sustainable use of ocean resources.

Case Studies

Examples of measurement science for oceans can be found in the selected case studies below:

Understanding our oceans - Salinity & Temperature

Oceans play a key role in regulating the global climate system. The interaction of oceans with the Earth’s atmosphere is strongly linked to seawater properties such as salinity and pH, which must be accurately monitored to identify long-term climate trends. However, measurements of these properties are challenging without a traceability chain to li...
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Building environmental metrology skills

The growing use of distance learning via the internet is opening up access to a diverse range of subjects to millions of students across the globe. Given metrology’s crucial role underpinning many areas of trade, industry and scientific research, modules dedicated to measurement science are an effective way of improving skills to support data quali...
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Understanding ocean acidity

Oceans are the largest active carbon sinks on Earth, absorbing more than a quarter of anthropogenic carbon emissions. The ocean’s interaction with the atmosphere, and its ability to absorb carbon dioxide, is strongly influenced by properties of seawater, such as salinity and acidity. Reliable and comparable measurements of these properties are of ...
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Monitoring ocean oxygen levels

Oceans play a vital role in regulating the global climate system and absorb more than a quarter of anthropogenic carbon emissions. Consequently, decreasing oxygen levels in the world’s oceans, driven by increasing ocean temperatures, are expected to have a major impact on the carbon cycle and our climate, as well as ocean life. Accurate measurement...
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