Since last 22 June, Sentinel 2A has been orbiting 786 km above us. One year after the launching of Sentinel 1, this new European satellite belongs to the Copernicus Programme for Earth observation from space, directed by the European Commission in partnership with the ESA (European Space Agency). By 2021, four other satellites in the Sentinel family will be launched. Their advanced functionality will enable us to observe the changes in agricultural areas, forests and even urban areas, and thus supply invaluable data for optimising resource management.
Credits: ESA-M, Pedoussaut 2015
Sentinel 2A, which will be joined in mid-2016 by its twin Sentinel 2B, provides optical performance unequalled to date. The satellite, which weighs over a tonne, is equipped with a system capable of sweeping a broader colour spectrum than those of its French and American equivalents, Spot and Landsat. Not only is it capable of supplying colour images of Earth (all visible colours in the spectrum) but also in infrared from 786 km above the earth. It can also sweep a distance of 290 km wide, with a resolution of 10 metres. Once linked to Sentinel 2B, every five days the two satellites will be able to produce the same image from the same location all over the world, giving us a precise vision of the changes in that location over time.
The Sentinel 2 will supply invaluable data in a number of areas, beginning with agriculture. Through the images obtained, it will be possible to measure the rate of land use and to become familiar with the type of crops grown. The comparison of images and their integration in sophisticated agronomical models will show evidence of long term changes so that yields of land on the country, continent or planetary scale can be forecast. By combining the satellite observations with meteorological data and other biophysical analyses, we can also measure the evapotranspiration (amount of water transferred to the atmosphere through evaporation at ground level and through the transpiration of plants) of crops in order to optimise irrigation and fertiliser use. Thus, it encourages the growth of a more sustainable agriculture, based on better resource optimisation, which is needed.
Credits: Copernicus data (2015)/ESA
In addition to cultivated land, Sentinel 2A and 2B will be useful for observing global vegetation and forests (measuring, in particular, the leaf-area index or the chlorophyll content). And because they will photograph the Earth from all angles, towns will not escape their lenses. The data collected will thus enable the impact analysis of urban expansion on the environment, and “improve urban planning in order to guarantee consistent sustainable development,” according to the Commission. The satellite images will also be used to better assess water stress, to anticipate droughts and floods, and to improve the understanding of the water cycle.
The Copernicus Programme, with a budget of €8.4 billion by 2020, will launch four satellites over the next five years equipped with new functionalities. Sentinel 3 will measure variables such as ocean topography or the surface temperature of the Earth and the oceans with very great precision. Sentinel 4 and 5 will survey atmospheric composition and Sentinel 6, which will be launched in 2020, will be focused on oceanography and climate. Including climate change, environment, emergency preparedness, agriculture, forestry, fishing, tourism, urbanism, etc. — the Sentinel family is ambitious. And it is also collaborative. The Copernicus data will be made available to governments, businesses, researchers and European citizens via dedicated Internet portals. According to the Commission, this free and open access to information will encourage the development of useful applications for many sectors.