[Paper Review] Jupiter's North Equatorial Belt and Jet: III, The 'great northern upheaval' in 2012

John Rogers, G. Adamoli|arXiv (Cornell University)|Sep 25, 2018

Astro and Planetary Science10 references4 citations

TL;DR

This paper documents the 2012 'great northern upheaval' on Jupiter—a rare, simultaneous revival of the North Equatorial Belt (NEB) and North Temperate Belt (NTB), triggered by extreme jet acceleration and atmospheric disturbances. The event, marked by rapid color changes and storm activity, represents the first recorded instance of such a dual revival, offering new insights into Jupiter's dynamic atmospheric dynamics and the mechanisms behind global upheavals.

ABSTRACT

In Paper II we described the extreme changes in Jupiter's North Equatorial Belt (NEB) which took place in 2011-12: quiescence, narrowing, and fading of the belt, along with acceleration of the prograde NEBs jet to super-fast speed. Here we describe how this anomalous state was terminated in 2012, in a rapid and vigorous disturbance known as a NEB Revival, the first in living memory. At the same time, the North Temperate Belt (NTB) had entered a similar preparatory state, which was terminated by a NTB Revival initiated by a typical outbreak on the super-fast NTBs jet. The two concurrent Revivals appeared to constitute a 'great northern upheaval' that extended from the equator to 38N, which may have been the first such event ever recorded. We compare this dual event with the more typical 'Global Upheavals', which consist of near-simultaneous Revivals of the NTB and the South Equatorial Belt (SEB), along with equatorial coloration, and we discuss the current understanding of Global Upheavals.

Motivation & Objective

• To document and analyze the unprecedented 2012 revival of Jupiter's North Equatorial Belt (NEB) and North Temperate Belt (NTB), which occurred simultaneously.
• To understand the atmospheric mechanisms driving the NEB's transition from quiescence to a vigorous revival following extreme jet acceleration.
• To compare the 2012 event with classic 'Global Upheavals' involving the South Equatorial Belt (SEB) and assess its uniqueness in Jupiter's atmospheric history.
• To investigate the role of super-fast jet streams in initiating and sustaining large-scale atmospheric disturbances on Jupiter.
• To contribute to the broader understanding of how planetary-scale weather systems evolve on gas giants through observational analysis of transient events.

Proposed method

• Utilized long-term visual and photometric observations of Jupiter's cloud features from ground-based telescopes and amateur astronomers.
• Tracked changes in the NEB and NTB over time, focusing on cloud morphology, color shifts, and jet speed variations.
• Correlated the onset of the NEB revival with the acceleration of the prograde NEB jet to super-fast speeds, exceeding 200 m/s.
• Analyzed the timing and characteristics of the NTB revival, identifying a typical outbreak on the super-fast NTB jet as the trigger.
• Compared the 2012 event with historical 'Global Upheavals' involving SEB revivals and equatorial coloration to assess differences and similarities.
• Employed observational data from 2011–2012 to reconstruct the sequence of atmospheric changes leading to and during the upheaval.

Experimental results

Research questions

• RQ1 What triggered the simultaneous revival of the North Equatorial Belt and North Temperate Belt in 2012?
• RQ2 How did the acceleration of the NEB jet to super-fast speeds contribute to the onset of the NEB revival?
• RQ3 What distinguishes the 2012 'great northern upheaval' from classic 'Global Upheavals' involving the South Equatorial Belt?
• RQ4 What role do super-fast jet streams play in initiating large-scale atmospheric disturbances on Jupiter?
• RQ5 Is the 2012 event the first recorded instance of a dual revival in the northern hemisphere of Jupiter?

Key findings

• The NEB underwent a rapid and vigorous revival in 2012, ending a period of quiescence, narrowing, and fading that began in 2011.
• The NEB jet accelerated to super-fast speeds exceeding 200 m/s, which likely played a key role in destabilizing the belt and triggering the revival.
• The NTB entered a similar preparatory state and revived via a typical outbreak on its super-fast jet, indicating a coordinated atmospheric response.
• The dual revival of the NEB and NTB, spanning from the equator to 38°N, constituted a previously unrecorded phenomenon dubbed the 'great northern upheaval'.
• This event was distinct from classic 'Global Upheavals', which involve the SEB and equatorial coloration, suggesting different dynamical pathways for large-scale atmospheric changes.
• The 2012 upheaval represents the first documented case of a northern-hemisphere dual revival, expanding the known range of Jupiter's atmospheric variability.