The European Space Agency's heat map of Spain and the Balearics from space. | European Space Agency


With the heat wave continuing to grip the Balearics, in fact it is the longest on record and is not expected to ease until next week, the European Space Agency has provided images of the heat from space.

Extreme heat warnings have been issued in several countries including France, Spain and Portugal, and deadly wildfires have forced thousands to flee their homes. The satellite images are an example of how the crisis is being viewed by satellites orbiting Earth.

The image, which uses data from the Copernicus Sentinel-3 mission’s radiometer instrument, shows the temperature of the land surface in southern France, Spain and northern Africa in the morning of 17 July.

It is worth noting the difference between air temperature and land-surface temperature. Air temperature, given in our daily weather forecasts, is a measure of how hot the air is above the ground. Land-surface temperature instead is a measure of how hot the actual surface would feel to the touch.

As the image clearly shows, in some places the surface of the land reached a whopping 55°C. Considering Copernicus Sentinel-3 acquired these data in the morning, the temperature would have increased through the afternoon.

Scientists monitor land-surface temperature because the warmth rising from Earth’s surface influences weather and climate patterns. These measurements are also particularly important for farmers evaluating how much water their crops need and for urban planners looking to improve heat mitigating strategies, for example.