Warm polar vortex on Saturn intrigues astronomers

[pmbryant]

A JPL news release: Feb 3 2005



Caption: This is the sharpest image of Saturn's temperature emissions taken from the ground; it is a mosaic of 35 individual exposures made at the W.M. Keck I Observatory, Mauna Kea, Hawaii on Feb. 4, 2004.

Saturn's Bull's-Eye Marks its Hot Spot
February 03, 2005

NASA astronomers using the Keck I telescope in Hawaii are learning much more about a strange, thermal "hot spot" on the tip of Saturn's south pole.

In the most precise reading of Saturn's temperatures ever taken from Earth, a new set of infrared images suggests a warm "polar vortex" at Saturn's south pole - the first warm polar cap ever to be discovered in the solar system. The vortex is punctuated by a compact spot that is the warmest place on the planet. The researchers report their findings in the Feb. 4 issue of the journal Science.

The images can be viewed at: http://www.nasa.gov/multimedia/imagegallery/.

A polar vortex is a persistent, large-scale weather pattern, likened to a jet stream on Earth in the upper atmosphere. On Earth, the Arctic Polar Vortex is typically located over eastern Canada and plunges arctic air to the northern plains in the United States. Earth's cold Antarctic Polar Vortex, centered over Antarctica, traps air and creates unusual chemistry, such as the effects that create the "ozone hole".

Polar vortices on Earth, Jupiter, Mars and Venus are colder than their surroundings. But new images from the W. M. Keck Observatory show the first evidence of such a polar vortex at much warmer temperatures than their surroundings. And the even warmer, compact region at the pole itself is quite unusual.

"There is nothing like this compact warm 'cap' in the Earth's atmosphere," said Dr. Glenn S. Orton, senior research scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., and lead author of the paper. "Meteorologists have detected sudden warming of the pole, but on Earth this effect is very short-term. This phenomenon on Saturn is longer-lived because we've been seeing hints of it in our data for at least two years."

...

More: http://www.jpl.nasa.gov/news/news.cfm?release=2005-020

[Squeegee]

1. I've read elsewhere...

that "Saturn has a warm pole". This headline gives me a slighly different picture of what they found.

[benburch]

2. Industrial activity?

I'm 99.999% mostly kidding... But; What if?

[On the Road]

3. As I Understand It

from an astronomer who studies Jupiter, those rotating bands of gas are mostly the result of differences in temperature caused by difference in exposure to sunlight. The South Pole seems to be turned towards the sun, and since it doesn't rotate, it stays sunlit rather than alternating between sunlight and darkness. Just a thought.

[pmbryant]

4. The odd thing is the abruptness of it.

From the original article from JPL (emphasis added):

The puzzle isn't that Saturn's south pole is warm; after all, it has been exposed to 15 years of continuous sunlight, having just reached its summer Solstice late in 2002. But both the distinct boundary of a warm polar vortex some 30 degrees latitude from the southern pole and a very hot "tip" right at the pole were completely unexpected. If the increased southern temperatures are the result of the seasonal variations of sunlight, then temperatures should increase gradually with increasing latitude. But they don't - the tropospheric temperature increases toward the pole abruptly near 70 degrees latitude from 88 to 89 Kelvin (-301 to -299 degrees Fahrenheit) and then to 91 Kelvin (-296 degrees Fahrenheit) right at the pole. Near 70 degrees latitude, the stratospheric temperature increases even more abruptly from 146 to 150 Kelvin (-197 to -189 degrees Fahrenheit) and then again to 151 Kelvin (-188 degrees Fahrenheit) right at the pole.

[On the Road]

5. I Missed That -- That IS Odd

Maybe it's a nonlinear relationships. The temperature differences actually don't seem all that great.

I would have expected that there would be gradual variations in temperature, wind speed, exposure to sunlight, etc. But instead it's broken into these wide uniform bands which slide past each other along well-defined boundaries. The pole is another boundary. That would be part of it. But there's probably something else at work.

For example: when a liquid is stirred, in a cup, heavier sediments to collect in the center. I wonder if a similar process is working here -- that for some reason, higher-temperature particles are collecting at the polls. Who knows?