This article Lowest recorded temperatures lists a -89 Degrees Celsius in Vostok, Antartica as the lowest recorded temperature. However, this other article List of weather records lists a −93.2 °C (−135.8 °F) on 10 August 2010, at 81.8°S 59.3°E. measured by Satellite. And this other article Coldest temperature on Earth in Antarctica lists a -97,8 °C , also using satellite measurements. Which one is the lowest temperature ever recorded on the surface of Earth then? Are satellite measurements reliable and do they count?
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$\begingroup$ The temperature measured at Vostok, Antarctica, was most likely measured using a thermometer, which would be very reliable, providing the thermometer was located in a Stevenson Screen. The trouble with satellite readings, is satellites are far away & their readings need to be calibrated with measurements taken by thermometers (within Stevenson Screens) on the surface. $\endgroup$– FredCommented Jul 1, 2019 at 14:05
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2 Answers
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The wikipedia article List of weather records explicitly states
This list does not include remotely sensed observations such as satellite measurements, since those values are not considered official records.[1]
Reference 1 in that article, a web archive link to a page on World Meteorological Organization Global Weather & Climate Extremes, adds that (emphasis mine)
Although claims of a "world-record coldest temperature" have been made for a remote-sensed location in Antarctica, the WMO official coldest temperature remains -89.2°C (-128.5°F) recorded on 21/7/1983 at Vostok, Antarctica. Official weather measurements are made at using standard equipment at a fixed height of between 1.25 m (4 ft 1 in) and 2 m (6 ft 7 in) above the ground for a fixed location over a specific length-of-record. Remoted-sensed values of temperature are not at this time regarded as official weather measurements.
There are many reasons why remote sensed temperature values (especially extreme ones) should not be considered as official with regard to record temperatures. First and foremost, those remotely sensed values are not measuring temperature. They instead measure proxies for temperature in the form of intensities of electromagnetic radiation in various frequency bands in the thermal infrared. The surface temperature is derived from these observations by a complex set of algorithms that make various assumptions regarding the nature of the sensed data.
These algorithms need to be calibrated against ground truth. These is no ground truth data for temperatures that low. The interpreted data were well outside the sensors calibrated rate. Moreover, the "ground truth" data is actually the recorded temperature at 1.25 meters to 2 meters above the ground. Official weather stations are supposed to be slightly elevated to avoid boundary layer effects. The sensed data on the other hand are primarily a result of surface temperatures, confounded by the fact that snow is a lousy thermal infrared emitter ("a good reflector is a lousy emitter") and confounded by contributions from the atmosphere between the surface and the satellite.
That said, those satellite readings almost certainly do indicate temperatures well below the reading at Vostok that officially counts as the lowest temperature recorded on the Earth.
answered Jul 2, 2019 at 10:49
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Ultralow Surface Temperatures in East Antarctica From Satellite Thermal Infrared Mapping: The Coldest Places on Earth p. 6127 says:
Validation studies of MODIS c5 and c6 LST for nonpolar regions, while limited, suggest that the surface temperature data are generally within 1 °C of the in situ measured thermal emission temperature (Wan, 2014), although the validation did not extend to this temperature range or surface type.
The coldest temperatures seem to be surface snow temperature. 2M air temperatures are a couple of degrees warmer.
