Perijove 12

By Maquet-80 on 2018-04-22 UT

During Perijove 12, several rewarding observations were possible. Here is a synopsis of some of them:

PJ12 Synopsis

The first row shows an enhanced cylindrical map of the Great Red Spot, and together with a turbulent eddy.
The left image in the second row shows, how the GRS comes into JunoCam's field of view while approaching Jupiter's south.
The right image in the same row shows a snapshot of the anticyclone NN-WS-4.
The third row shows enhanced polar maps of some of the northern and southern circumpolar cyclones.
The left image in the fourth row shows mesoscale waves in latitudes near the equator. Noteworthy is the line of bright popup clouds, which ressemble some kind of cirrus clouds in this observation, possibly induced by wind shear.
The right image in the same row shows the high phase angle of inbound images. This specific image was selected, since it also shows a distinct moon shadow.
The image in the last row is derived from four stacked methane band images, and from one RGB image. The methane band data define the brightness, the RGB data hue and saturation of the combined image. The methan-bright south polar hood is very distinct. The surrounding seam appears to be a little darker in methane band than in RGB images, when related to areas further to the north.

For the northern and southern CPCs, as well as for NN-WS-4, and for some other areas, more than image could be taken. The quality of the images allows for resolving cloud motion in short animations.



  1. comment by Philosophia-47 on 2018-04-28 10:49 UT

    Report on PJ12 images:  Here is the ZIP file of figures for Part II (hi-res images of mid/low latitudes).

    --John Rogers

    • comment by Philosophia-47 on 2018-04-28 22:41 UT

      PS:  In Part II, FigC9_PJ12_GRS-STrD_cyl-map_Gerald.jpg   should also be credited to Seán Doran.

  2. comment by Philosophia-47 on 2018-04-28 10:48 UT

    Report on PJ12 images:  Here is the ZIP file of figures for Part I (the polar regions).

    --John Rogers.

  3. comment by Philosophia-47 on 2018-04-28 10:47 UT

    Report on PJ12 images, Part II: here is the PDF.

    --John Rogers

  4. comment by Philosophia-47 on 2018-04-28 10:46 UT

    Here is a report on the PJ12 images. Since our paper was published (Adriani et al., ‘Nature’, March 8), we are now able to post more details of the on the circumpolar cyclones (CPCs) and polar hazes – topics on which the JunoCam team is preparing further publications.  Hence, this report is in two parts: (I) The polar regions; (II) Middle and lower latitudes.  Each part will be posted as a PDF with mini-figures, plus a ZIP file containing the full-size figures. [The PDF of Part I is attached to this Comment; others to follow.]

    PJ-12 was likely to be the last perijove this year at which the spacecraft would be turned so that the MWR, as well as JunoCam, could view the track below, also getting widespread coverage of the planet inbound and outbound.  And JunoCam got the jackpot. 

    Highlights of the images include:

    --The approach images, at high phase angle, revealed the complete pattern of northern hemisphere haze bands in swirling, eddying detail for the first time.

    --An anticyclonic white oval (AWO) in the NNTZ, called NN-WS-4, was viewed close up and revealed spiral ridges of clouds and rapid rotation.

    --In the NEB, a miniature ‘barge’ was viewed close up.

    --High-quality images of the Equatorial Zone revealed ‘mesoscale waves’ to be very widespread.

    --The spacecraft flew 10º  p. the p. end of the GRS, and right over the region where the STropD was spilling turbulence into the STropZ.  Thus JunoCam obtained unique closeups of this phenomenon, as well as complete views of the GRS as the spacecraft moved south, which will enable an animation of the complex dynamics.

    --The view of the south polar pentagon of cyclones was perhaps the best yet, due to the displacement of the pentagon maximally into sunlight, and top-quality image return. These views confirm the cyclic behaviour of the pentagon, and give several new clues to its dynamics. It is still accompanied by a long haze band, which was brilliantly lit at the terminator.