Super-cold thunderstorm sets temperature record

Posted: March 27, 2021 by oldbrew in Clouds, research, Temperature, weather
Tags:

Anvil_Cloud

Anvil of a thundercloud over Columbia [image credit: Eulenjäger @ Wikipedia]

But that’s not the whole story. It seems from long-term data ‘that these super-cold thunderstorms may be increasing in frequency. There have been as many such events across the globe in the past three years as there were in the 13 years before that.’ Could this be in some way related to the big decline in sunspot activity over the last two solar cycles?
– – –
We’ve all seen those majestic anvil storm clouds that form on a hot summer’s day, but what do you think is the temperature right at the very top? – asks BBC News.

It’s very cold, obviously; at high altitude it is well below freezing.

But would you be surprised to learn it is sometimes below even -100C?

Indeed, scientists have just published research showing the top of one tropical storm cloud system in 2018 reached -111C. This is very likely a record low temperature.

It was seen on 29 December that year, just south of the equator in the western Pacific. The measurement was made by a passing American satellite, Noaa-20.

When a powerful upward draft reaches the top of the lower atmosphere, or troposphere, it will normally flatten and spread out to form that classic anvil shape.

But if the storm is very energetic, the upward movement of air can punch through the troposphere’s ceiling, the tropopause, to keep on rising into the stratosphere, the next layer up in the atmosphere. In the 2018 event, the cloud top was at about 20.5km in altitude.

“It’s called an overshooting top,” explains Dr Simon Proud, a Nerc research fellow in satellite remote sensing at the National Centre for Earth Observation and Oxford University, UK.

“Overshooting tops are reasonably common. We get them over the UK as well, sometimes – like last August when we had a number of massive storms. But this was a very big overshoot. Normally, an overshooting top cools by about 7C for every kilometre it goes above the tropopause; and this one was about 13C or 14C cooler than the tropopause – so, a pretty big overshoot,” he told BBC News.

Dr Proud and Scott Bachmeier, a research meteorologist at the University of Wisconsin-Madison, US, report the event in a paper in the journal Geophysical Research Letters.

Full article here.

Comments
  1. erl happ says:

    In the absence of ozone, that part of the atmosphere that we call the ‘Stratosphere’ and the ‘Mesosphere’ would not exist. A negative lapse rate of temperature with altitude (as in the troposphere) would be observed through to the ionosphere where heating by very short-wave radiation splits the oxygen molecule and the lapse rate would be diminished and gradually reversed, at least in daytime.

    The inversion of the lapse rate in the stratosphere is due to the heating of the air by ozone that derives most of the required energy from the Earth’ own radiation streaming towards space, day and night.

    So the phenomenon of very cold temperatures above the equator when tropospheric air that contains little ozone is elevated to great heights, is unremarkable.

    In fact, there is more energy gathered by ozone and imparted to other molecules in the troposphere than in the stratosphere, accounting for the inflation of temperature variations in the upper half of the atmospheric column (above 500 hPa). It is here that one can observe that a 1C increase at the surface is commonly coincidental with a 4C increase at 200 hPa. The hearting aloft, due to the presence of ozone is commonly layered, as is the cloud cover, and is coincident with a loss of ice cloud cover.

    Ozone heating is evident most of all in the winter hemisphere where solar radiation is truncated by low sun angles. And it is here that ozone proliferates in winter and is elevated to the top of the atmosphere by ‘extratropical’, more strictly speaking, ‘polar cyclones’ that constitute the margins of the jet stream also known as the ‘polar front’, or the polar vortex. These cyclones have the same low central pressure as in a tropical cyclone or tornado but are 1000 times more extensive in the area affected.

    Recently it has become possible to map incursions of stratospheric air into the troposphere. See https://www.cpc.ncep.noaa.gov/products/stratosphere/strat_int/
    Unfortunately, the implications for weather and climate change are not yet appreciated. It doesn’t suit the catastrophic warming narrative.

    Ozone heating of adjacent molecules is limited by the frequency of collisions between molecules, in other words, atmospheric density. So, the heating power of ozone diminishes with increasing elevation.

    When one observes this phenomenon the notion that the atmosphere is heated largely by direct contact with the surface (conduction) is seen to be false. In fact, the upper half of the atmosphere is sufficiently heated by infrared radiation from the Earth to change the lapse rate dynamic, and with it cloud cover and the Earth’s albedo.

    It follows that the study of the dynamics governing the proportion of ozone in the air is critical to the understanding of climate change. This is well illustrated by the step change that occurred in surface temperature in the tropics and the Pacific Ocean in 1976-8 that propagated from an increase in the temperature of the Antarctic upper atmosphere that impacted the stratosphere, globally, all the way to the Arctic.

    It also follows that the de-limitation of a ‘troposphere’ and a climate irrelevant, non-convecting ‘stratosphere’ inhibits the development of an understanding of the atmospheric dynamics that account for weather and climate.

    How has this happened? Mathematicians have taken over climate science. Flights of fancy in climate science relate to an excess of armchair ‘theorizing’ in relation to plain old fashioned ‘observation’. ‘Modelling’ is a mathematical exercise. Too clever by half. Heads in the sand.

  2. oldbrew says:

    Not seen this article before…

    MAY 6, 2020
    Cold air rises—what that means for Earth’s climate

    A better understanding of the vapor buoyancy effect and its stabilizing role in the tropics can also improve cloud and thunderstorm simulations, as well as climate models, the study said.

    “Now that we understand how the lightness of water regulates tropical climate, we plan to study whether global climate models accurately represent this effect,” said the study’s lead author, Seth Seidel, a graduate student researcher at UC Davis.

    https://phys.org/news/2020-05-cold-air-riseswhat-earth-climate.html

    Evaporation?

  3. erl happ says:

    Yes, higher water vapour content yields lower density. This will result in uplift.
    Release of latent heat in condensation and sublimation adds energy further reducing density/
    As the air ascends it cools via decompression.
    But the lower temperature can only be sustained by the arrival of air undergoing decompression and the maintenance of a low ozone status.

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