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Sentinel-3 and the ocean carbon conundrum

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Each year, about a quarter of the carbon dioxide we release into the atmosphere ends up in the ocean, but how it happens is still not fully understood. The Sentinel-3A satellite is poised to play an important role in shedding new light on this exchange.

Initially, the fact that the oceans are absorbing a significant amount of the carbon dioxide we pump into the atmosphere by burning biomass and fossil fuels would appear to be a good thing. However, as more carbon dioxide dissolves into the oceans, it leads to ocean acidification, making it difficult for some marine life to survive.

Monitoring and understanding the carbon cycle is important because carbon is the fundamental building block of all living organisms. Also, the process of carbon moving between the oceans, atmosphere, land and ecosystems helps to control our climate.

Over the last four years an international team of scientists and engineers have been using satellites along with measurements from ships and pioneering cloud computing techniques to study how carbon dioxide is transferred from the atmosphere into the oceans.
Their new work, published in the Journal of Atmospheric and Oceanic Technology, reveals that the seas around Europe absorb an astonishing 24 million tonnes of carbon each year. This is equivalent in weight to two million double decker buses or 72 000 Boeing 747s.

The team are making their data and cloud computing tools, the ‘FluxEngine’, available to the international scientific community so that other groups can analyse the data for themselves.

They hope that making tools like this available to everyone will improve the transparency and traceability of climate studies. It should also help to accelerate scientific advancement in this important area.

Jamie Shutler from the University of Exeter said, “The information we are gathering using satellites is essential for monitoring our climate, but these observations are not always easily available for other scientists to use.

“This new development means that anyone can use our cloud tools and data to support their own research.”

They are also now looking to Europe’s Copernicus Sentinel satellites to provide vital information for this area of research.

Sentinel-3A was launched on 16 February and once commissioned for service it will measure the temperature of the sea surface, currents, winds, waves and other biochemical factors.

The unique aspect of Sentinel-3A is that its instruments make simultaneous measurements, providing overlapping data products that carry vital information to estimate carbon dioxide ‘fluxes’.

To calculate the flux of gases between the ocean and the atmosphere, it is necessary to know the solubility of carbon dioxide in the seawater, together with the speed of gas transfer.

Importantly, the solubility is determined by a combination of sea-surface temperature and salinity, while the ocean surface wind and wave environment govern the speed at which carbon dioxide is transferred.

All this information from just one satellite makes the Sentinel-3 mission a near-perfect tool to estimate the exchange of carbon dioxide between the atmosphere and the global ocean, as well as seasonal, year-to-year and regional patterns in the exchange.

ESA’s Sentinel-3 mission scientist, Craig Donlon, said, “The use of satellite data to provide a more informed and complete set of baseline data is helping to improve our understanding of carbon cycling.

“The ability for individual scientists to run and rerun their own flux calculations is a new and powerful way of working together in an open science world.”

While satellites enable us to monitor the global oceans easily, shipboard measurements remain essential because we can’t monitor everything from space.

Andy Watson, also from the University of Exeter, commented, “Good knowledge of the ocean uptake and release of carbon dioxide is essential for predicting climate change. Eventually, most of the carbon dioxide we release will find its way into the oceans.

“This project will provide the most accurate estimates that we have and is accessible to anyone.”

Source: http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus/Sentinel-3/Sentinel-3_and_the_ocean_carbon_conundrum

Third Sentinel satellite launched for Copernicus

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The third ESA-developed satellite carrying four Earth-observing instruments was launched today, ready to provide a ‘bigger picture’ for Europe’s Copernicus environment programme.

The 1150 kg Sentinel-3A satellite was carried into orbit on a Rockot launcher from Plesetsk, Russia, at 17:57 GMT (18:57 CET; 20:57 local time) on 16 February.

After a first burn starting about five minutes after liftoff and a second about 70 min later, Rockot’s upper stage delivered Sentinel-3A into its planned orbit, 817.5 km above Earth. The satellite separated 79 min into the flight.

The first signal from Sentinel-3A was received after 92 min by the Kiruna station in Sweden. Telemetry links and attitude control were then established by controllers at ESA’s ESOC operations centre in Darmstadt, Germany, allowing them to monitor the health of the satellite.

After the launch and the early orbit phase of three days, controllers will begin checking that all the satellite elements are working and subsequently calibrate the instruments to commission the satellite. The mission is expected to begin operations in five months.

“With the successful launch of Sentinel-3 we are now looking forward to how our teams of experts will steer this mission into its operational life – like they have done the first two satellites of the series,” said ESA Director General Jan Woerner.

“This is another demonstration of the broad range of competence we have at ESA from the early design phase until the operational mission in orbit.”

The mission is the third of six families of dedicated missions that make up the core of Europe’s Copernicus environmental monitoring network. Copernicus relies on the Sentinels and contributing missions to provide data for monitoring the environment and supporting civil security activities. Sentinel-3 carries a series of cutting-edge sensors to do just that.

Over oceans, it measures the temperature, colour and height of the sea surface as well as the thickness of sea ice. These measurements will be used, for example, to monitor changes in Earth’s climate and for more hands-on applications such as marine pollution and biological productivity.

Over land, this innovative mission will monitor wildfires, map the way land is used, check vegetation health and measure the height of rivers and lakes.

“This is the third of the Sentinel satellites launched in the less than two years – and it is certainly a special moment. It also marks a new era for the Copernicus Services, with Sentinel-3 providing a whole range of new data with unprecedented coverage of the oceans,” said the Director of ESA’s Earth Observation Programmes, Volker Liebig.

Sentinel-3B, its twin satellite, is scheduled for launch next year.

Data from all the Sentinels are used worldwide and are free of charge for all users.

Source: http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus/Sentinel-3/Third_Sentinel_satellite_launched_for_Copernicus