Rare cloud formation seen in Antarctica

[Kevin Rooney]

Speaking of cloud formations - here's a news item I saw on Yahoo. Apparently it's as cold in the southern hemiphere as is hot in the northern. The temps for these cloud formations was -189F!

And, it's snowing in South Africa - apparently a rarity.
________________________________________________________________
Tue Aug 1, 7:35 PM ET

HOBART, Australia - Some of the coldest temperatures on Earth brought a rare cloud formation to the skies over Antarctica, scientists said Tuesday.

Meteorological officer Renae Baker captured spectacular images of the nacreous clouds, also known as polar stratospheric clouds, last week at Australia's Mawson station in Antarctica.

The clouds only occur at high polar latitudes in winter, requiring temperatures less than minus 176 degrees Fahrenheit. A weather balloon measured temperatures at minus 189 degrees Fahrenheit on the day the photos were taken.

Resembling airborne mother-of-pearl shells, the clouds are produced when fading light at sunset passes through water-ice crystals blown along a strong jet of stratospheric air more than six miles above the ground.

"Amazingly, the winds at this height were blowing at nearly 230 kilometers (143 miles) per hour," Baker said on the Australian government's Antarctic Division's Web site.

Australian Antarctic Division atmospheric scientist Andrew Klekociuk said the clouds are seldom seen, but are occasionally produced by air passing over polar mountains.

"You have to be in the right part of the world in winter, and have the sun just below your horizon to see them," he said.

On the Net:

http://www.aad.gov.au/

 

[Paradox]

Gorgeous Kevin, thank you. One of my greatest joys is clouds. They are beautiful, spontaneous, something you can share with anyone within shouting distance, and free.

The following is some pretty dramatic skud, I saw out my living room window about two months ago. The picture is on my wall as I write. I am happy to share it.

skud

One of the most visually appealing books I have ever read was entitled "Clouds of the World". An oversize book that went out of print in the early 1980's or so. It had a detailed discussion on the formation of the various types of clouds, as well as pictures and types of weather and other things to be expected when certain clouds were observed. The pictures were incredible. I found it in the library at Buffalo State College. I have subsequently tried to find it at several used book stores and on the internet but have not seen it since.

 

[sardog1]

Interesting and slightly ominous news.

There are a couple errors in the cited temperatures. The original report from the Australian Antarctic Division states that the minimum temperature required for such cloud formation is -80C and that the clouds were observed at -87C. The formula for converting from Celsius to Fahrenheit is:

(Temperature in degrees Celsius * 9/5) + 32 = temperature in degrees Fahrenheit.

The Fahrenheit equivalents are thus respectively -80C=-112F and -87C=-124.6F, not -176F and -189F. Someone erroneously subtracted 32 when it should have been added.

(FWIW -- The record minimum temperature for the Earth's surface is usually reported as -128.6F at Vostok, Antarctica.)

 

[Maddy]

Really beautiful pics! Thanks for posting these.

 

[bogorchis]

Rare cloud formation

Great information, Kevin! Thanks for posting the web site. Sounds a bit colder then Baxter in the winter!
bogorchis

 

[Kevin Rooney]

Interesting and slightly ominous news.

There are a couple errors in the cited temperatures. The original report from the Australian Antarctic Division states that the minimum temperature required for such cloud formation is -80C and that the clouds were observed at -87C. The formula for converting from Celsius to Fahrenheit is:

(Temperature in degrees Celsius * 9/5) + 32 = temperature in degrees Fahrenheit.

The Fahrenheit equivalents are thus respectively -80C=-112F and -87C=-124.6F, not -176F and -189F. Someone erroneously subtracted 32 when it should have been added.

(FWIW -- The record minimum temperature for the Earth's surface is usually reported as -128.6F at Vostok, Antarctica.)

Sardog1 -

Good catch. And as you probably know, they were reporting cloud temps, not ground.

And yes, Ginger, a tad colder than Baxter! Haven't seen you in awhile - hope all is well.

Kevin

 

[Whiteman]

But did you read the fine print?

It looks like not everybody is happy about these so-called nacreous clouds. Did you notice what Dr. Klekociuk said (and I know, everybody thinks this fellow is always the sour apple in the barrel):

"These clouds are more than just a curiosity. They reveal extreme conditions in the atmosphere, and promote chemical changes that lead to destruction of vital stratospheric ozone" Dr Klekociuk said.​

And, from another wet blanket department:

Polar stratospheric clouds (PSCs) play a central role in the formation of the ozone hole in the Antarctic and Arctic. PSCs provide surfaces upon which heterogeneous chemical reactions take place. These reactions lead to the production of free radicals of chlorine in the stratosphere which directly destroy ozone molecules. (Australian Antarctic Division )​

Oh well, they sure are purty. I just hope we don't see them hovering over the Crawford Path!