Saturday, January 10, 2015

Is the North Equatorial Band shrinking again?

Measurement of NEB thickness using the 22:32 UT. Blue channel.

Thickness of the North Equatorial Band
  
2011
2012
2015
10,401 km
15,005 km
11,188 km (n=8)
Table showing thickness measurements of the NEB in km along this hemisphere.

Based on 8 measurements taken along the NEB as detected in the image above, an average value of 11,188 km for the thickness of the NEB has been calculated. Looking at past measurements of the same north equatorial band, results point to a varying thickness; however if these past measurements are assumed to be indicative of a trend, then the latest measurements could indicate a shrinking of this Jovian belt. 

Further verification is required, especially with regards to intermediate measurements during the period 2013-2014. 

It is interesting to note the prominent rifts found along the NEB between 120 and 150 degrees, and again between 150 and 160 degrees, shown in a lighter colour.

The GRS

According to NASA's Goddard Space Flight Center, recent NASA Hubble Space Telescope observations confirmed that the Great Red Spot now is approximately 16,496 km across, and is considered as being less than half the size of this feature measured since the 1930s.

Using the blue channel superimposed on the Equirectangular projection above, the dimensions of the GRS is measured to be around 12,443 x 16,937 km, which is close to NASA's measurements.

http://science.nasa.gov/science-news/science-at-nasa/2014/15may_grs/

The GRS wakefield

The giant wakefield generated by the rotation of the GRS against the laminar flow of the SEB band is made evident by the changes in albedo as a result of horizontal and vertical mixing from the different atmospheric layers of Jupiter. The length of the wakefield shown in the image below approximates to 63,914 km (Earth's diameter: 12,742 km).

2015-01-07 22:44-46 UT [I:36.6  II:279  III:183.3]. South is up

The Equatorial Region

Image enhancement of the equatorial region shows an intricate distribution of blue festoons principally connected to the southern part of the NEB that are being affected by the strong equatorial flow and are extended along the flow. The resulting fine plumes are very conspicuous and can be seen as 'tracers' of the shear flow in this region. 


The South Temperature Belt

South to the STB are three conspicuous white (anticyclonic) ovals. These white ovals are between 4000-5000 km wide (roughly the same width as the Australian continent).

2015-01-07 22:44-46 UT [I:36.6  II:279  III:183.3]. Enhanced colours. South is up.
SH: 2015-01-07 22:29-33 UT [I:27.7  II:270.2  III:174.4]
NH: 2015-01-07 22:29-33 UT [I:27.7  II:270.2  III:174.4]

































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