On Dec. 29, 2018, a weather satellite peering down over the Pacific spotted a cluster of towering thunderheads with extremely cold cloud tops. A recently released study confirms one of the clouds was measured at minus-168 degrees Fahrenheit, establishing a record for the coldest cloud-top temperature reliably measured globally.
For comparison, that’s almost 40 degrees colder than the lowest temperature ever measured on Earth’s surface — minus-129.3 degrees in Antarctica in 1983. The coldest reading obtained in North America was minus-81 degrees, measured in Canada’s Yukon Territory in 1947.
The results offer new insight into exactly how cold the tops of clouds embedded in deep thunderstorm activity can get, as well as highlight the enormous technological strides making these modern-day observations possible.
The paper, written by Simon Richard Proud at the National Center for Earth Observation in Oxford, Britain, and Scott Bachmeier of the Cooperative Institute for Meteorological Satellite Studies at the University of Wisconsin at Madison, was published March 22 in the American Geophysical Union’s Geophysical Research Letters.
“The idea for this collaboration began when Simon contacted me about the [minus-165 degree] cloud-top temperature sensed by [a NOAA satellite] with Typhoon Kammuri on 30 November 2019,” wrote Bachmeier in an email. “We had both taken a look at this event using geostationary and polar-orbiting satellites. [We] thought it might be good to take a look back in time at all available satellite data and make sure there were no other tropical cyclone or thunderstorm events over the tropical West Pacific that were possibly colder.”
Indeed there were. After combing through years of data, the pair of scientists happened upon one lone thunderstorm that exhibited shockingly low temperatures.
“In general, the further back you go, the less reliable the temperatures,” Proud said in an email. “To look at historical statistics, we used the MODIS sensor onboard NASA’s Aqua satellite as it is one of the more reliable, giving more than 16 years of very consistent temperature data.”