Europe has experienced its second heat wave of the month, with ground temperatures reaching as high as 55°C in certain regions. A satellite image released by the European Space Agency (ESA) distinctly illustrates the extent of ground heating from the Iberian Peninsula to North Africa.
Color scale of the image
The image was captured by the Copernicus Sentinel-3 mission on Wednesday, June 23. The data was collected in the morning, local time.
The color scale extends from purple and dark red — representing soil temperatures of up to 55°C in central Spain, western France, and northern Africa — to blue, which signifies cooler mountainous regions. Cloud cover is depicted in white.
What precisely was measured by the satellite?
The SLSTR radiometer recorded temperatures of 48°C in Madrid, 44°C in Rome, 46°C in Poitiers, France, and Zaragoza, Spain. In North Africa, temperatures were even higher; in Tunisia, for example, the ground reached 49°C.
The heat wave in Europe as observed from space. Copernicus Sentinel-3 image dated June 23, 2026. Credit: ESA. Source: European Space Agency, ESA / youtube.com.
Understanding the distinction between these values and data obtained from weather stations is of paramount importance. Rocks, sand, and asphalt possess a much higher heat retention capacity, resulting in the Earth’s surface consistently being warmer than the air at a height of two meters, which is the standard measurement height for weather temperature.
An explanation of the operating principle of a radiometer
The Sea and Land Surface Temperature Radiometer (SLSTR) is among the quartet of instruments onboard Sentinel-3. This highly precise sensor functions across nine spectral channels, spanning from the visible to the thermal infrared spectrum.
Its data are utilized in agriculture, as well as for monitoring urban heat islands and forest fires. The radiometer continues the lineage of ATSR instruments that have been operational on European remote sensing satellites since 1991 and provides global daily coverage with a resolution of 1 km in the thermal infrared band.
Heat dome and its causes
The ongoing heat wave in Europe has been attributed to a persistent atmospheric circulation pattern. A so-called heat dome was formed over Western and Central Europe — a stable area of high pressure located between two areas of lower pressure.
The summer heat in Europe is traditionally not associated with the El Niño–Southern Oscillation. Although satellite data in the tropical Pacific Ocean are already showing early signs of this phenomenon forming in the Pacific Ocean, it is not considered the primary factor contributing to the current unprecedented temperatures across the continent. According to Météo-France, France experienced its highest temperature ever recorded this week, while in the United Kingdom, the June temperature record established in 1976 was surpassed twice within a
Provided by: esa.int
