IPB

Welcome Guest ( Log In | Register )

 
Reply to this topicStart new topic
Red Spot: Why no eye?, Why does the Great Red Spot not have an eye like a hurricane?
hendric
post Sep 12 2008, 02:51 PM
Post #1


Director of Galilean Photography
***

Group: Members
Posts: 710
Joined: 15-July 04
From: Austin, TX
Member No.: 93



Looking at Ike pounding the Texas coast here, I was thinking...Why do the GRS and lesser storms on Jupiter not have eyes like Hurricane's here on Earth? Does Jupiter's rapid rotation somehow prevent their formation, or does an eye require water vapor?

Hmm...a quick Google search didn't turn up any explanations as to why hurricanes have eyes to begin with, so maybe my question is flawed. smile.gif


--------------------
Space Enthusiast Richard Hendricks
--
"The engineers, as usual, made a tremendous fuss. Again as usual, they did the job in half the time they had dismissed as being absolutely impossible." --Rescue Party, Arthur C Clarke
Mother Nature is the final inspector of all quality.
Go to the top of the page
 
+Quote Post
Juramike
post Sep 12 2008, 03:20 PM
Post #2


Senior Member
****

Group: Moderator
Posts: 2676
Joined: 10-November 06
From: Pasadena, CA
Member No.: 1345



Here's a link that describes hurricane eye and eyewall formation: http://www.aoml.noaa.gov/hrd/tcfaq/A11.html

It seems the eye is kept open by having centrifugal force throwing stuff outside, and also by having gently descending (and warming) air at the center.

I'm not sure why some Hurricane eyes tend to cloud over from time to time. (And I'm not sure if this is related to eyewall replacement cycles, either.)

I wonder if the difference between hurricanes on Earth and the red spot may have something to due to the relative thickness of the two features. (I'm assuming the Earth's hurricanes are much thinner <15 km).

-Mike


--------------------
Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
Go to the top of the page
 
+Quote Post
Juramike
post Sep 12 2008, 03:30 PM
Post #3


Senior Member
****

Group: Moderator
Posts: 2676
Joined: 10-November 06
From: Pasadena, CA
Member No.: 1345



Ah ha! Found something much more relevant!

http://www.wunderground.com/blog/JeffMaste...p;tstamp=200611

The south polar Saturnicane is probably a better analog to Earth's hurricanes.

Jupiter's Red Spot is not considered hurricane-like since it doesn't posess "an eyewall surrounded by a cloud-free eye".

-Mike


--------------------
Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
Go to the top of the page
 
+Quote Post
john_s
post Sep 12 2008, 04:09 PM
Post #4


Member
***

Group: Members
Posts: 528
Joined: 3-December 04
From: Boulder, Colorado, USA
Member No.: 117



One fundamental difference- the Great Red Spot and similar storms on Jupiter are anticyclonic (high-pressure), not cyclonic (low-pressure) like terrestrial hurricanes. For reasons way beyond my expertise, Jovian anticyclonic storms are well-organized while its cyclonic storms are a jumbled mess.

John.

Go to the top of the page
 
+Quote Post
Juramike
post Sep 12 2008, 04:49 PM
Post #5


Senior Member
****

Group: Moderator
Posts: 2676
Joined: 10-November 06
From: Pasadena, CA
Member No.: 1345



Wiki-link here: http://en.wikipedia.org/wiki/Great_Red_Spot#Great_Red_Spot

(The full article describes other atmospheric phenomena of Jupiter)


--------------------
Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
Go to the top of the page
 
+Quote Post
Juramike
post Sep 12 2008, 06:30 PM
Post #6


Senior Member
****

Group: Moderator
Posts: 2676
Joined: 10-November 06
From: Pasadena, CA
Member No.: 1345



QUOTE (john_s @ Sep 12 2008, 11:09 AM) *
One fundamental difference- the Great Red Spot and similar storms on Jupiter are anticyclonic (high-pressure), not cyclonic (low-pressure) like terrestrial hurricanes.


Actually, hendric, I'm really, really glad you asked this question. This is something that's been bothering me for quite a while now, hopefully someone can set me straight.


Most hurricanes have surface lows (inflow), but upper level highs (outflow). The cumulonimbus clouds trace out the inflow and convective bands. The upper atmosphere divergence strengthens the lower level convergence. (All that humid air's gotta go somewhere). I'm not sure, but I think upper level outflow might be observable by examining the fine structure in the water vapor loop imagery over time using a rotating coordinate frame (another project for Spin-O-Vision).

Here's the best site I've found to explain hurricane structure (use the tab in the window to scroll through): http://www.newmediastudio.org/DataDiscover...urr_Struct.html

"Upper level flow and the anticyclonic jet. As air leaving the center of the hurricane reaches an elevation of about 12 km above sea level (200 mb level), it produces high pressure near the tropopause, and divergent flow away from the focus of the hurricane. This upper level outflow circulates in an anticyclonic direction, typically at a radius of 300 km, and is termed the anticyclonic jet. "


What I'm wondering (and honestly don't know), is if the upper level outflow (anti-cyclone) we see from the Great Red Spot is coupled to a lower level low pressure system. Could it be that the Great Red Spot is a super-thick big hurricane, with the cyclonic bands hidden way down deep, but the upper level anticyclonic bulge evidenced by the high dark red cloud layers?

-Mike


--------------------
Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
Go to the top of the page
 
+Quote Post
Guest_PhilCo126_*
post Sep 12 2008, 07:47 PM
Post #7





Guests






Jupiter's Atmospheric Pressure near that latitude?
Go to the top of the page
 
+Quote Post
hendric
post Sep 16 2008, 07:08 PM
Post #8


Director of Galilean Photography
***

Group: Members
Posts: 710
Joined: 15-July 04
From: Austin, TX
Member No.: 93



Thanks everyone, I'll give these links a read!


--------------------
Space Enthusiast Richard Hendricks
--
"The engineers, as usual, made a tremendous fuss. Again as usual, they did the job in half the time they had dismissed as being absolutely impossible." --Rescue Party, Arthur C Clarke
Mother Nature is the final inspector of all quality.
Go to the top of the page
 
+Quote Post

Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 24th April 2014 - 05:37 PM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is a project of the Planetary Society and is funded by donations from visitors and members. Help keep this forum up and running by contributing here.