Satellite images reveal Prague’s heat islands
An unusually early and intense heat wave spread from North Africa across Europe before the summer solstice, bringing temperatures more typical of July and August.
“In parts of Spain and France, temperatures are more than 10°C above average for this time of year, breaking records. This is combined with drought in many parts of Europe,” the World Meteorological Organization (WMO) stated in June.
Since the end of the 19th century, the beginning of the boom in CO2 emissions, which warms our planet, the average global temperature has increased by about 1.1 degrees Celsius. Experts fear that extremes in weather may become the norm and that waves will continue to worsen as the climate continues to change.
The current images published last week by the European Space Agency (ESA) show the different temperatures at the earth’s surface in Milan, Paris and even in Prague on the afternoon of June 18.
Image of Milan, Italy
Photo: NASA/JPL-Caltech
In Prague, you can notice more prominent areas of so-called heat islands, especially in the Holešovice locality, in Libni near the O2 arena or in industrial areas in the south-eastern part of the capital. The temperature inside the city at the surface there attacked the value of 45 degrees.
Prague thermal islands. As you can see, greenery helps. The data was measured on June 18, 2022 by the ECOSTRESS instrument located on the International Space Station ISS. pic.twitter.com/daydn2vWXv
— Michal Václavík (@Kosmo_Michal) July 9, 2022
According to the ESA, the hottest places are clearly visible, and according to the scientists, the favorable “cooling” effect of parks, various forms of vegetation and water bodies can be deduced from the image.
Urban heat island is an urban development that shows significantly higher temperatures than the surrounding area. The main cause is the covering of the original area of vegetation by roads and buildings. Asphalt and concrete do not have the ability to use the received solar radiation and transform it into chemical or other energy, as happens with higher plants; at the same time, they have a greater tendency to absorb incident light and heat radiation. Secondary to this is the wasted heat energy supplied to individual houses and apartments. As the transformation of the original landscape increases, so does the temperature in the centers of the heat islands. |
For several consecutive days in mid-June, people in many European cities had to deal with air temperatures above 40 degrees Celsius. E.g. in some parts of the UK, temperatures rose to over 33 degrees in June.
The thermal islands of Paris
Photo: NASA/JPL-Caltech
But it wasn’t just about Europe. In Tokyo, Japan, it was above 35°C for five days in a row last month. It was the record there for June since records began in 1875.
Mapping the Earth
The relevant facility on the ISS that provided the data is called ECOSTRESS and belongs to the Jet Propulsion Laboratory (JPL) of the US National Aeronautics and Space Administration (NASA) in California. The device is intended for remote temperature research of terrestrial ecosystems, so that scientists can better understand, for example, how much water plants need.
The ECOSTRESS facility on the ISS
Photo: NASA
“It continues to map the impact of extreme heat in cities around the world, including recent record-breaking heat waves in both Europe and the US. This data can be used to identify hotspots, vulnerable areas and assess possible approaches to mitigate the heat,” commented JPL’s Glynn Hulley.
For ESA, the ECOSTRESS instrument is valuable as it helps develop a new Sentinel satellite for Europe’s Copernicus Earth Remote Sensing Service, specifically the Land Surface Temperature Monitoring (LSTM) mission. “LSTM will provide surface temperature data at a similar resolution,” added Benjamin Koetz from ESA.
For comparison, ESA also offers a view of the earth’s surface in the greater part of Europe, from data taken by the Copernicus Sentinel-3 mission also on June 18, just a little earlier.
June heat wave in Western Europe
Photo: contains modified Copernicus Sentinel (2022) data, processed by ESA, CC BY-SA 3.0 IGO
The “golf” turf problem
According to meteorologist Dagmar Honsová, everyone can actually help with the “cooling” of cities – e.g. when working with a lawnmower – just by not requiring a “golf” lawn.
“The temperature of the soil below the length of the lawn is up to 15 °C higher than with bare soil. And with tropical high-quality daily evaporation, not as much water evaporates from the soil if the length of the grass is longer,” she commented on this issue for Novinky.
Honsová reminded that in Central Europe, another heat wave is also “lurking” behind the door.
“The start of next week from July 18 will bring highs of up to 38C in the afternoon highs. Added to this is just a little cloud cover. The physiologically equivalent temperature, which indicates the complex effect of the environment on a person – i.e. the influence of incident sunlight or radiation from buildings – will be much higher in cities,” she pointed out.