Juno perijove 6, May 19, 2017 Options

[Gerald]

Voting for Perijove 06 started yesterday, and it will last for another almost 7 days.

This time, I'm not quite free of bias, since I'm interested in an extension of the polar time-lapse sequence, especially in a coverage of the north and south polar FFRs and the presumed edge of the respective polar haze disks. I think - well, I'm rather certain - that it's possible to infer short-time dynamics of the FFRs, and of the vortices near the edge of the haze disk. Due to the expected good contact to Earth during the PJ-6 pass we have a good chance to obtain overlapping images of these regions.
More in the discussion section on the missionjuno site. Of course, there are other interesting targets, too; see Glenn's and John Rogers' (Philosophia-47) comments.
A full latitude coverage would allow for a pole-to-pole animation.

[Bjorn Jonsson]

As I mentioned previously, these latest JunoCam images are awesome. I took a fairly detailed look at one of the images I posted earlier with particular attention to cloud elevation differences. First an unusual image. This is a perfectly flat DEM with several spikes - their shadows show the direction of sunlight in one of the JunoCam images I posted earlier:



And here is the corresponding JunoCam image. This is one of the images I posted earlier but here I have added some annotations:




A. Bright, high altitude clouds that usually seem to be isolated or to occur in small clusters.

B. These clouds are similar to (A) in color and altitude. But unlike (A) they appear elongated, probably parallel to the wind direction. At least in some cases they indicate high wind speeds - clouds like these are visible at lower resolution in Voyager images showing the northeast periphery of the Great Red Spot where the wind speed is very high.

C. I suspect that here we are seeing the darker and lower cloud deck through tenuous and mostly transparent high altitude clouds. This is more obvious when looking at the red channel only.

D and E. Here JunoCam may have directly observed/imaged the elevation difference between the dark clouds and the less dark clouds south of the 'color/brightness transition'. Areas indicated by (D) appear slightly darker than areas indicated by (E). When taking into account the direction of the shadows in the DEM/spike shadow render above, the areas indicated by (D) may be in shadow caused by the brighter clouds south of the brightness/color transitions while the areas indicated by (E) are not in shadow.

F. These clouds seem somewhat similar to (A) but they occur in far bigger clusters. Apparently they also might be at a slightly lower altitude - this is not obvious though.

G. Possible shadows hinting at elevation differences but color/brightness variations are also a possibility. Features like this are very common.

[jccwrt]

And here is the corresponding JunoCam image. This is one of the images I posted earlier but here I have added some annotations:




A. Bright, high altitude clouds that usually seem to be isolated or to occur in small clusters.

B. These clouds are similar to (A) in color and altitude. But unlike (A) they appear elongated, probably parallel to the wind direction. At least in some cases they indicate high wind speeds - clouds like these are visible at lower resolution in Voyager images showing the northeast periphery of the Great Red Spot where the wind speed is very high.

C. I suspect that here we are seeing the darker and lower cloud deck through tenuous and mostly transparent high altitude clouds. This is more obvious when looking at the red channel only.

D and E. Here JunoCam may have directly observed/imaged the elevation difference between the dark clouds and the less dark clouds south of the 'color/brightness transition'. Areas indicated by (D) appear slightly darker than areas indicated by (E). When taking into account the direction of the shadows in the DEM/spike shadow render above, the areas indicated by (D) may be in shadow caused by the brighter clouds south of the brightness/color transitions while the areas indicated by (E) are not in shadow.

F. These clouds seem somewhat similar to (A) but they occur in far bigger clusters. Apparently they also might be at a slightly lower altitude - this is not obvious though.

G. Possible shadows hinting at elevation differences but color/brightness variations are also a possibility. Features like this are very common.

Going to make some interested-layman interpretations of the meteorology here.

One observation is that the two largest A-type clouds seem to be found at eddy inflection points, right where the white clouds meet the brown clouds. I wonder if these might be supercell-like convective systems that are popping up along the boundary of white and brown clouds, and whose development is aided by favorable upper level conditions created by air diverging as it rounds the inflection point of the eddy.

F-type clouds seem to be more embedded within the local flow and are vaguely oriented in "streets" parallel to the flow direction. These are kind of reminiscent of the cloud streets that tend to form in the dry slot of a mature low-pressure system, or in clusters of multicell convection in strong upper level wind regimes where the updrafts tend to form trains.

B-type clouds look like cirrus streaks formed getting blown off the tops of the more intense convective clouds, and if you look closely at the A-type cloud clusters near the center of the image, you can see some of these streaks beginning to form as elongated cloudtops on individual convective cells.


Maybe a more clear example of what Bjorn is getting at with point C can be seen just to the right of the F at left center. There is an extremely dark brown cloud rotating around the top of the eddy that has an apparently sharp edge, but if you look closely you can see that it continues underneath the lighter clouds. (Not at a computer where I can highlight this but if anyone is having issues seeing what I'm talking about I'll try to have something up within a day)