Copernicus eye on air quality returns first data

Sentinel-5P tropospheric nitrogen dioxide measurements over Europe, Africa, Middle East, and India, averaged from April 2018; pollution emitted by big cities and shipping lanes is clearly visible (Copernicus Sentinel data processed by KNMI)

11 July 2018

Sentinel-5P, the Copernicus programme mission dedicated to monitoring air quality from space, is formally in operation with the first release of data. The spacecraft, launched in October 2017, returned “first light” in December and, after testing and calibration, is now sending home data on carbon monoxide, nitrogen dioxide, ozone, methane and other atmospheric gasses.

The spacecraft carries what is being billed as the most advanced multispectral imaging spectrometer to date; the Dutch-built Tropomi sensor provides sufficient resolution – up to 7 x 3.5 km – to locate where pollutants are being emitted, effectively identifying pollution hotspots. Harry Förster, of the Netherlands Space Office, described Tropomi’s resolution as “simply unprecedented – in combination with the improved sensitivity of the detectors we now have a spectrometer that is about 10 times better than its predecessor.”

Air pollution

According to the European Space Agency, which realises and operates the Sentinel satellites on behalf of the European Commission, initial data have highlighted air pollution as emitted by big cities and shipping lanes through measurements of nitrogen dioxide over Europe, Africa, the Middle East, and India. ESA Earth observation director Josef Aschbacher has described Sentinel-5P as ushering in “a new era in air quality measurement”.

Philippe Brunet, European Commission director of space policy, Copernicus and defence, hailed the first data milestone as highlighting the “European Union’s contribution to combatting the global issue of air pollution”. Sentinel-5P will also contribute to services such as volcanic ash monitoring for aviation safety and warnings of high level UV radiation.

Sentinel-5P will operate in tandem with NASA-NOAA’s Suomi NPP, ultimately trailing it by 3.5km in its nearly polar orbit – inclination of 98.7° at an altitude of 824km.

Sentinel-5P – as in 5 Precursor – was developed to reduce data gaps between Envisat, which operated from launch in 2002 until it was lost in 2012, and Sentinel-5. That mission will be a payload carried by one of the polar orbiting MetOp satellites operated by Europe’s EUMETSAT weather service and due to launch in 2021.

Also still to come in the Sentinel series another atmosphere composition monitoring mission, Sentinel-4, a payload to ride in geostationary orbit with EUMETSAT’s MTG-I third generation Meteosat and due to launch in early 2021. And, Sentinel-6, scheduled to launch in 2020, will carry a radar altimeter to measure global sea-surface height, primarily for operational oceanography and for climate studies.

As with all satellite and in-situ data from Copernicus, Sentinel-5P’s output is freely available worldwide to policy makers and environmental agencies, scientists and other users – including developers of commercial applications. Data can be downloaded or accessed and processed in the cloud via any of five new Data and Information Access Services – or DIAS. Formally launched last month, the DIAS idea is to help users cope with the vast volume and variety of Copernicus data, by providing one-source access to a searchable catalogue of imagery and measurements. Users can still download Copernicus data directly from EU portals – and there are well in excess of 100,000 registered users, plus many more accessing data through partners such as NOAA in the USA – but the DIAS are expected to “revolutionise” the way the data is accessed.

Speaking in June at an event in Baveno, Italy, to mark the 20th anniversary of the agreement that kicked off the Copernicus programme, European commissioner Elżbieta Bieńkowska said the vast quantity of data coming from Copernicus was a barrier to use by entrepreneurs, small companies and start-ups. Such smaller users, she said, cannot sustain the investment in information and communications technology needed to work with so much data: “This is a crucial initiative to make sure that all users…can enjoy a seamless access to Copernicus data.”