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Re: Jupiter's warm 8ºN subtropical jet feature?
Posted: Mon Aug 24, 2020 10:44 pm
by neufer
https://en.wikipedia.org/wiki/Jet_stream#Subtropical_jet wrote:
<<Jet streams are fast flowing, narrow, meandering air currents in the atmospheres of some planets, including Earth. On Earth, the main jet streams are located near the altitude of the tropopause and are westerly winds (flowing west to east). Their paths typically have a meandering shape. Jet streams may start, stop, split into two or more parts, combine into one stream, or flow in various directions including opposite to the direction of the remainder of the jet. The strongest jet streams are the polar jets, at 9–12 km above sea level, and
the higher altitude and somewhat weaker subtropical jets at 10–16 km.
One factor which contributes to a concentrated jet is more applicable to the subtropical jet which forms at the poleward limit of the tropical Hadley cell, and to first order this circulation is symmetric with respect to longitude. Tropical air rises to the tropopause, and moves poleward before sinking; this is the Hadley cell circulation. As it does so it tends to conserve angular momentum, since friction with the ground is slight. Air masses that begin moving poleward are deflected eastward by the Coriolis force, which for poleward moving air implies an increased westerly component of the winds.
https://en.wikipedia.org/wiki/NASA_Infrared_Telescope_Facility wrote:
The NASA Infrared Telescope Facility (NASA IRTF) is a 3-meter (9.8 ft) telescope optimized for use in infrared astronomy and located at the Mauna Kea Observatory in Hawaii. It was first built to support the Voyager missions and is now the US national facility for infrared astronomy, providing continued support to planetary, solar neighborhood, and deep space applications.
Re: A planet-wide Jupiter-feature / line / streak
Posted: Mon Aug 24, 2020 11:41 pm
by BDanielMayfield
And the relevance to the line on Jupiter is ...?
Re: A planet-wide Jupiter-feature / line / streak
Posted: Tue Aug 25, 2020 4:29 am
by neufer
BDanielMayfield wrote: ↑Mon Aug 24, 2020 11:41 pm
And the relevance to the line on Jupiter is ...?
If this supposed
"line" on Jupiter
actually runs through
Ann's festoons then it clearly represents the well known progression of large grayish-blue irregular "hot spots" which march eastward at the northern edge of the white Equatorial Zone which were the prime focus of
the Galileo atmospheric Probe.
I spent 40 years as a NOAA atmospheric scientist during which I designed the GOES 6.5 micron water vapor channel
specifically to examine Subtropical Jet subsidence features at around the 300 mb level in Earth's troposphere. As such, I find these rather similar looking subsidence features on Jupiter quite interesting.
Re: A planet-wide Jupiter-feature / line / streak
Posted: Tue Aug 25, 2020 4:44 am
by varadinagypal
Chris, your words make sens.
I would really like to see a one revolution earlier image of Jupiter's side in question -- cause I have no data, and very few amateurs publish in an obvious and searchable manner -- and no, text embedded into an image is not searchable. As I photographed it two days later, when those longitudes became available to me again, all I found were some darker spots to the north of the dark protrusion chosen as a position of reference.
As for why the darker spots were on bands, as knots, and not in lighter regions, it could well be an artifact of the sharpening. At latitude N47 and with a city below Jupiter, my balcony is not the ideal observatory -- and in a very short time, it won't be an observatory thanks to "real estate development" (and I've been politically correct here). So this is kinda all the resolution I can squeeze out of the instruments and the given atmospheric conditions.
