The satellite is the part of the EU’s Copernicus Earth observation programme, and will contribute to daily forecasts of air quality, track where greenhouse gases are being released in unprecedented detail, and verify if the planet’s ozone layer is recovering after being damaged by CFCs in the 20th Century.
There’s only one instrument on board, called Tropomi, developed by scientists in the Netherlands.
“You have one satellite instrument measuring the complete globe – it means that you have one calibrated instrument measuring everywhere – it means that you can compare the pollution levels in Europe directly with those in China and United States,” says Pieternel Levelt, principal investigator for Tropomi and head of Satellite R&D at Dutch national weather service KNMI.
Sentinel-5P will fly on a polar orbit, circling the globe 40 times a day, scanning a swath 2,600 kilometres wide, with each pixel of representing 3.5 by 7 kilometres. That level of precision means the scientists and climate monitoring teams will be able to distinguish the difference between pollution from sources which are located quite close together, for example the port of Rotterdam and the city. They also hope to gain a better understanding of how pollution from some regions and cities travels with weather systems to other parts of the world – for example how pollution from the US reaches across to Ireland, or how pollution from the UK reaches Scandinavia.
Sentinel-5P will also contribute to better pollution forecasts for us Earthlings. Air pollution isn’t just a nuisance, it’s a killer – the WHO reported that 3.7 million people died in 2012 from conditions related to outdoor air pollution. The satellite will be looking for some of the key nasties like nitrogen dioxide, low level ozone, carbon monoxide and formaldehyde, all of which can be very harmful to humans. These gases are commonly produced by fossil fuels burned by vehicles and industrial processes, but also volcanic emissions.
A key question Sentinel-5P should answer is the state of the high-altitude ozone layer, a protective band of gas that allows life on Earth to thrive by absorbing harmful radiation from space. The ozone layer was damaged by mankind’s emission of CFC gases, but these were banned from January 1989 following the UN’s Montreal Protocol. However, there is still a ‘hole’ in the ozone layer above the South Pole between September and October, and globally there is still thought to be a lower level of ozone than in the 1960s.
Pieternel Levelt told Euronews how important this mission is for ozone monitoring: “The ozone layer is often looked at as something which is solved. We understand the chemistry, we understand the dynamics, we know how to improve, to get the ozone back, basically, by reducing the cooling agents (CFCs). But of course it’s important to measure it, to prove that that your measures work, and we don’t expect a complete recovery before 2050, 2060, so we need these measurements to know that the ozone layer is there, because it’s a pre-requisite for life on Earth- without the ozone layer we cannot live here.”
Sentinel-5P joins the other Sentinel satellites already in orbit, representing the space component of Copernicus, the world’s most ambitious Earth observation programme, overseen by the European Commission. Already in space are Sentinels 1 to 4. Sentinel-1A and 1B will providing all day and all night radar images, which are very useful for monitoring events like flooding; Sentinel-2A and 2B deliver high-resolution optical images of land use;
Sentinel-3A, launched on 16 February 2016, provides data for services relevant to the ocean and land; and Sentinel-4 is measuring trace gases and aerosols from a more distant geostationary orbit.
Upcoming soon is Sentinel-6, which follows on the sea surface height measurements taken by the Jason series of satellites, the missions which have been vital to quantifying global sea level height for climate studies.