Austrian researchers are using innovative satellites to measure the total amount of water present both on land, but also below the surface. The level of underground drought in Europe is so great that it changes the total mass of our Blue Planet.
Europe has been facing a historic drought for several years: the global level of groundwater has been low since 2018, despite the few episodes of intense rains, and the floods, which several countries have experienced. After the dark years in terms of precipitation, 2018 and 2019, no real improvement managed to take place, until the summer of 2022 marked by a severe drought over 75% of the European continent.
Satellites estimate the total mass of the Earth
A new generation of satellites makes it possible to accurately quantify the level of drought at depth, and not just surface drought (also called agricultural drought), which easily improves depending on weather conditions. These satellites, Tom and Jerry, are in orbit about 490 kilometers from Earth, and are spaced 200 kilometers apart. These two satellites which “run behind each other” (hence their name) travel around the Earth at a speed of 30,000 km/h. They do this 15 times a day around the orbit of our planet and this allows them to take a picture of the entire Earth in the space of a month.
The purpose of these satellites is to analyze all the changes in the total mass of the Earth, which depends among other things on the level of groundwater, but also of lakes, seas and oceans. To arrive at determining the evolution of the quantity of water present at depth, the researchers must then subtract the mass of snow, ice and of course water present at the surface. The totality of terrestrial water reserves is ultimately the addition of groundwater, glaciers, snow, soil moisture, and bodies of water (lakes, rivers, etc.). By subtracting all other water masses from their calculations, scientists are able to determine the exact amount of groundwater present by region of the globe.
The deep dryness of the soil causes the mass of the Earth to decrease
The effects of heavy precipitation also have an impact on the mass of the Earth recorded by the satellites: this increases significantly when the Asian monsoon takes place. As well as the melting of the ice, which reduces the mass of the earth: between 200 and 300 gigatonnes of ice disappear each year from Greenland. The conclusions of the Technical University of Graz (Austria) on Europe are alarming, especially for Central Europe. Water levels are extremely low in countries that were not considered dry areas before: Germany and Austria in particular. This lasting deficit will lead to long-term water supply problems, the researchers conclude. This decrease in the level of groundwater is so significant at European level that it is clearly reflected in the evolution of the Earth’s mass.
For the time being, calculations on the evolution of the Earth’s mass take time and require several months of work. But in the future, the researchers believe that variations in Earth’s mass will be available in real time.
