-111°C Coldest thunderstorm clouds form over the Pacific Ocean

Severe thunderstorm clouds that formed over the Pacific Ocean in 2018 reached their lowest temperatures on record, according to a new study.

The very top of the storm cloud reached a bone-chilling -111 degrees Celsius, colder than any storm cloud previously measured.

According to a statement from Britain’s National Earth Observation Centre, thunderstorms and tropical cyclones (a type of cyclonic low-pressure storm) can reach very high altitudes – 18 kilometers above the ground – where the air is much colder.

But -111 degrees Celsius is on a whole other level. According to the statement, the top of the storm cloud was about 30 degrees Celsius cooler than a typical storm cloud.

The beast of a storm takes shape overhead about 400 kilometers south of Nauru in the southwest Pacific Ocean on Dec. 29, 2018, with cloud temperatures measurable by infrared sensors on the U.S. NOAA-20 satellite.

(Proud& Bachmeier, Geophys. Res. Lett., 2021)

When a storm reaches the top of the troposphere, which is the lowest layer of the Earth’s atmosphere, it usually spreads into an anvil shape. However, if the storm is very energetic, it will shoot into the next layer, the stratosphere.

This phenomenon is called a “supershot top” and pushes storm clouds to very high altitudes where it is very cold.

Superejecta are “quite common,” lead author Simon Proud, a researcher at the National Earth Observation Centre and the University of Oxford, told the BBC. he said that normally, superejecta cool by 7 degrees Celsius for every kilometer of stratospheric rise.

But this storm was particularly extreme.” This storm achieved unprecedented temperatures, pushing the limits of what current satellite sensors can measure,” Proud said in a statement.

“We are finding that ultra-low temperature storms seem to be becoming more common.”

He added that in the past three years, scientists have recorded the same extremely cold temperatures in clouds as in the previous 13 years of historical data.” This is important because thunderstorms with colder clouds tend to be more extreme and more hazardous to people on the ground due to hail, lightning and wind.”

According to the BBC, this particular storm may have been inspired by a combination of very warm water and eastward-moving winds in the region. However, it is unclear why the low-temperature storm clouds are increasing.

“We now need to understand whether this is due to our climate change, or whether the ‘perfect storm’ weather conditions that happened to form have produced an explosive increase in extreme thunderstorms over the past few years.” Proud said.

The results of the study were published March 22 in the journal Geophysical Research Letters.

The data was not measured directly with a thermometer, but was extrapolated from multiple remote sensing data after re-examining satellite photos, so it was repeatedly verified and published after more than 2 years.

The altitude of 18 km is located at the top of the troposphere – the bottom of the stratosphere, where the general temperature is between -50°C and -60°C. -111°C is far below the normal temperature, so it is news.

The air mass at the bottom expands adiabatically as it rises, and the temperature will be lower than the rest of the air at the same altitude. In general, the more rapidly the air mass rises, the lower the temperature (too late to absorb heat from nearby gases).