NASA solves how a Jupiter jet stream shifts into reverse

Posted: December 19, 2017 by oldbrew in atmosphere, Cycles, research, solar system dynamics, Temperature, wind

Jupiter [image credit: NASA]

The caption to the explanatory video says: ‘When scientists look at Jupiter’s upper atmosphere in infrared light, they see the region above the equator heating and cooling over a roughly four-year cycle’.

Speeding through the atmosphere high above Jupiter’s equator is an east-west jet stream that reverses course on a schedule almost as predictable as a Tokyo train’s, says Now, a NASA-led team has identified which type of wave forces this jet to change direction.

Similar equatorial jet streams have been identified on Saturn and on Earth, where a rare disruption of the usual wind pattern complicated weather forecasts in early 2016.

The new study combines modeling of Jupiter’s atmosphere with detailed observations made over the course of five years from NASA’s Infrared Telescope Facility, or IRTF, in Hawai’i. The findings could help scientists better understand the dynamic atmosphere of Jupiter and other planets, including those beyond our solar system.

“Jupiter is much bigger than Earth, much farther from the Sun, rotates much faster, and has a very different composition, but it turns out to be an excellent laboratory for understanding this equatorial phenomenon,” said Rick Cosentino, a postdoctoral fellow at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the paper published in the Journal of Geophysical Research-Planets.

Earth’s equatorial jet stream was discovered after observers saw debris from the 1883 eruption of the Krakatoa volcano being carried by a westward wind in the stratosphere, the region of the atmosphere where modern airplanes achieve cruising altitude. Later, weather balloons documented an eastward wind in the stratosphere. Scientists eventually determined that these winds reversed course regularly and that both cases were part of the same phenomenon.

The alternating pattern starts in the lower stratosphere and propagates down to the boundary with the troposphere, or lowest layer of the atmosphere. In its eastward phase, it’s associated with warmer temperatures. The westward phase is associated with cooler temperatures.

The pattern is called Earth’s quasi-biennial oscillation, or QBO, and one cycle lasts about 28 months. The phase of the QBO seems to influence the transport of ozone, water vapor and pollution in the upper atmosphere as well as the production of hurricanes.

Jupiter’s cycle is called the quasi-quadrennial oscillation, or QQO, and it lasts about four Earth years. Saturn has its own version of the phenomenon, the quasi-periodic oscillation, with a duration of about 15 Earth years.

Researchers have a general understanding of these patterns but are still working out how much various types of atmospheric waves contribute to driving the oscillations and how similar the phenomena are to each other.

Continued here.

Screen shot from the video

  1. oldbrew says:

    Huge Storms Disrupted Jupiter’s Fastest Jet Stream in 2016

    Recurrent jet stream disturbances provide glimpses of what lies beneath the gas giant’s thick upper cloud cover.

    By Sarah Stanley 27 June 2017

    In late 2016, a quartet of huge storms disrupted the usually stable flow of a rapid atmospheric jet stream that encircles Jupiter. Multiple instruments snapped photos of the event [see link below], and Sánchez-Lavega et al. have now used these images to investigate the progression of the disturbance.

    The 2016 storm event is the most recent in an irregular cycle of similar events that disrupt the structure of the North Temperate Belt, one of several atmospheric bands that give Jupiter its stripes. The first sign of such an event is a high-altitude plume, a convective storm structure composed of upwelling gas that appears to astronomers as an elongated bright spot thousands of kilometers wide.
    – – –
    Cycles of activity in the Jovian atmosphere
    Author – L. N. Fletcher
    First published: 28 May 2017

    1 Introduction
    2 Time Variability of Jupiter’s Banded Structure
    3 Jupiter’s Belts in 2016
    4 Cyclic Activity in the North Temperate Belt
    5 Identifying the Causes of Jovian Variability
    – – –
    Jupiter’s North Equatorial Belt expansion and thermal wave activity ahead of Juno’s arrival
    Authors – L. N. Fletcher et al
    First published: 28 July 2017

    The dark colors of Jupiter’s North Equatorial Belt (NEB, 7–17°N) appeared to expand northward into the neighboring zone in 2015, consistent with a 3–5 year cycle.

  2. tallbloke says:

    Earth’s QBO is ~28 months and we’ve discussed the drivers before.
    Jupiter’s QQO is about 1/3 of its orbital period and 1/5 of the J-S conjunction period.
    Saturn’s is about half its orbital period and 3/4 of the J-S conjunction period.

  3. oldbrew says:

    TB – a ratio of about 2 Saturn QPO : 7 Jupiter QQO looks plausible.

    The same ratio cropped up here.
    The model says: 2 S-H = 7 J-H = 9 Jupiter-Saturn conjunctions (Jose cycle).

    And here

    Miles Mathis writes: ‘This brings Jupiter’s charge influence down to 3.5 times that of Saturn.’

    3.5:1 = 7:2

  4. oldbrew says:

    Gravity waves cause Jupiter jet stream to change course: NASA
    By PTI | Published: 19th December 2017 02:01 PM |

    Last Updated: 19th December 2017 02:16 PM

    WASHINGTON: A jet stream speeding through the atmosphere high above Jupiter’s equator changes its course almost on a schedule due to gravity waves, NASA scientists say.

    Similar equatorial jet streams have been identified on Saturn and on Earth, where a rare disruption of the usual wind pattern complicated weather forecasts in early 2016.