Glagla? We do not know, in the Sonoran Desert. You will say to me: it is a desert, after all. Yes, but still: 80.8 degrees were measured there, in this desolation worthy of Lucky Luke, located between Mexico, California and Arizona.
Measured in 2019, this is a new record for global temperature readings, reports the site Science. The precedent dates back to 1913, with 56.7 ° C recorded in the Death Valley, in the United States, where the average summer temperature often exceeds 45 ° C.
Ground temperature
These new data come from a high resolution satellite measurement method. Important note: it reads the temperature on the ground, and not at a height of 1.5 meters, under cover and in a ventilated compartment, as is usually the case in the 11,000 stations of the World Meteorological Organization (WMO ).
At this level, temperatures are often higher than in the air, especially on sunny days, “a bit like leaving your car in an outdoor parking lot during the summer, or walking on sand. hot ”, explains to Science David Mildrexler of the Eastern Oregon Legacy organization. Surfaces are heated both by the air, but also by the energy dissipated by the planet, what scientists call the Earth’s radiative balance.
New hot … and cold spots
These are two NASA satellites, Terra and Aqua, respectively in orbit since 1999 and 2002, which are at the origin of these results. They take on board a “spectral radiometer for medium resolution imaging”, MODIS according to its English acronym. When the sky is clear, the instrument measures physical phenomena on the surface of the earth and the oceans, including the dissipated energy.
In 2011 continues Science, David Mildrexler and his team had already recorded 70.7 ° C in Lut, Iran, thanks to MODIS.
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Since then, scientists have improved their acquisition software to gain in resolution. They went from 5 kilometers per pixel to 1 kilometer per pixel, highlighting new hot spots, often in areas far from weather stations. And cold spots too, in Antarctica, of course, where -110.9 ° C was validated in 2016, twenty degrees colder than the previous record of 1983, the article said.
As for the possible relationship with global warming, it has not been established. But the record for the Sonoran Desert coincides with a particularly intense episode of La Niña, a climatic phenomenon accompanied by a cooling of the central Pacific and even drier conditions in the deserts.
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