A group of international researchers is developing "pioneering
techniques" to monitor the acidity of oceans from space, using
satellites that can orbit the Earth up to 700 km above us in
hard-to-reach areas, like the Arctic, much faster than before.
According to the scientists, a number of existing satellites can
be used for the task, including the European Space Agency's Soil
Moisture and Ocean Salinity (SMOS) sensor that was launched in
2009 and NASA's Aquarius satellite launched in 2011.
"Satellites are likely to become increasingly important for
the monitoring of ocean acidification, especially in remote and
often dangerous waters like the Arctic. It can be both difficult
and expensive to take year-round direct measurements in such
inaccessible locations," said lead researcher Dr Jamie
Shutler, of the University of Exeter.
"We are pioneering these techniques so that we can monitor large
areas of the Earth's oceans allowing us to quickly and easily
identify those areas most at risk from the increasing
acidification," he said.
Each year, over a quarter of global CO2 (carbon dioxide)
emissions from burning fossil fuels and cement production are
absorbed by the planet's oceans. This process makes the seawater
become more acidic and as a result more difficult for some marine
life to exist. Growing CO2 emissions, along with the rising
acidity of seawater, could devastate some marine ecosystems over
the next century, ecologists warn, and that's why endless
monitoring of changes in ocean acidity is vital. A report issued
before a United Nations climate summit in New York put 2014 world
carbon emissions 65 percent above levels in 1990, despite
repeated promises of curbs and a shift to renewable energies. It
said world emissions could reach 43.2 billion tons in 2019, with
12.7 billion from China alone, as the number one carbon emitter.
Current methods of measuring temperature and salinity to determine acidity are restricted to in situ tools and measurements from research vessels. Since such vessels are expensive to run and operate, the approach limits the sampling only to small areas of the ocean, however. The groundbreaking techniques use satellite mounted thermal cameras to take ocean temperatures, while microwave sensors check salinity. These measurements can be used to assess ocean acidification more quickly and over much larger areas than has been possible before, researchers say.
"In recent years, great advances have been made in the global provision of satellite and in situ data. It is now time to evaluate how to make the most of these new data sources to help us monitor ocean acidification, and to establish where satellite data can make the best contribution," said Dr Peter Land from Plymouth Marine Laboratory, the lead author of the paper, set to be published on Tuesday in the journal Environmental Science and Technology.
Scientists from the University of Exeter, Plymouth Marine Laboratory, Institut français de recherche pour l'exploitation de la mer (Ifremer) and the European Space Agency took part in the research.
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