[9] Jupiter in 2010: Interim report: Northern hemisphere
John Rogers, Hans-Joerg Mettig, Gianluigi Adamoli, Michel Jacquesson & Marco Vedovato (BAA & JUPOS project).


This is the second half of an interim report on the phenomena recorded in amateur images of Jupiter in the first half of the 2010 apparition.   In the N. Tropical Region, changes continue across the NEB.  Most of the large NEBs dark features have disappeared and extraordinary super-fast motions (up to DL1 = -78 deg/month) have reappeared.  Several distinct NEB rifts are very conspicuous and dynamic, often interacting with barges.  New barges and white ovals have appeared in the aftermath of last year's NEB broadening event.  A merger of two anticyclonic white ovals was better observed than any previous event of this kind. In the narrow residual N. Tropical Zone, the drift rate of a narrow blue band has been estimated for the first time, revealing a rapid drift on the flank of the NTBs jetstream.        

In the N. Temperate Region, the N. Temperate Disturbance (NTD) still existed up till August, with an active rifted region at its p. end confirming that this is a key component of a NTD.  However, very few retrograding or recirculating spots could be found, which may be why the NTD now appears to be clearing away.  Meanwhile there is continuous intense activity of spots in the NNTBs jetstream.        

In an Appendix, the NTD is described in more detail.  This leads to a general conjecture about the behaviour of anticyclonic dark spots in zones on the planet: that they are unusually free to wander in latitude and thus in speed, possibly because they are only shallow vortices, compared to other types of spots which are more stable and possibly deeper.

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Please see copyright notice in the Introduction to the report.