Australian Space Weather Agency Revises Solar Cycle 24 Start, Adding 6 Months

Gary Gulrud (09:48:12) :
“Still, with heliomagnetic models projecting a fall-off for SC#24 & Hathaway’s conveyor model predicting a fall-off for SC#25
The two predictions are contradictory and cannot be taken together like that. If Hathaway is correct on #25, then #24 must be large.”
Although not in the loop, I would call the source of the #24 prediction, Hathaway’s geomagnetic model, and suppose the source (from context) for #25 to be Dikpati’s conveyor model (not to slight anyone not on the NASA team).
The source of the #24 prediction [“the fall-off for SC#24”] is [because of the ‘heliomagnetic’ qualifier] probably my own and Ken Schattens’ predicitons using the solar polar fields. Those predictions point to a small #24 [Rmax~75]. The ‘conveyor belt’ model is Dikpati’s model. Hathaway’s geomagnetic model is kind of inconsistent with Dikpati model because the Dikpati model operates with an internal memory of ~20 years or more and Hathaway’s geomagnetic peak model uses the peak just before the start of the cycle, thus a memory of 5-6 years. That both models predict a high cycle does not mean [in spite of Hathaway’s claim] that ‘they support each other’. This is a point that Hathaway carefully avoids. When pressed [as I have done during the Panel meetings, his weak defense is that perhaps the peak 5-6 years before the maximum was caused by something that occurred ~15 years earlier [for a total pf ~20 years], but what that ‘something’ might be he cannot say.

statePoet1775 (15:59:55) :
Since cosmic rays are charged, I wonder if the earth’s magnetic field significantly changes where they hit.
It does not.

Pamela Gray (19:17:39) :
Please explain the Bz north versus south and the Earth’s magnetosphere. What happens when Earth decided to go South instead of North? What happens when the Sun’s measured Bz matches Earth’s? And what is the magnetopause?
Lots of stuff to learn before it begins to make sense.
First the magnetopause. The solar wind dominates far from the Earth. Near the Earth, the Earth’s magnetic field dominates. At some point, then, the two must be more or less equal. That is called the magnetopause, where ‘pause’ is used in the same sense as in tropopause, being the boundary between the stratosphere and the troposphere.
Then the Bz. Try to take two toy magnets and put then on a table at some distance from each other, but lined up so they are parallel to each other. Then try to move them closer together, still lined up, moving one with one hand and the other with the other hand. As they come closer and closer, you’ll find that if the magnetic poles are aligned (N-S, N-S), the two magnets begin to resist being brought together and it becomes harder and harder to push them together. If, on the other hand, the magnets are oppositely aligned (N-S, S-N), they do not resists being brought together and actually begin to attract each other. If you think about, the magnetic field lines ’emanating’ from the magnets [with a little arrow on them to show their direction – from one pole to the other], then you can see that in the first case we described, the field lines from the two magnets at a point halfway between the magnets point in the same direction, while in the other case they point in opposite directions.
Now, this is not precisely what happens between the solar wind and the Earth. It is LOT more complicated, and there are electrical currents and moving plasma involved, but it is useful ‘shorthand’ for the fact that the magnetic fields of the solar wind and the Earth interact differently depending on their orientation. And when a component of the solar wind magnetic field, called Bz, along the Earth’s magnetic dipole axis is oppositely aligned with the field line going northwards from the Earth’s southern magnetic pole [which is actually the magnetic north pole] to the Earth’s northern magnetic pole [which is actually a magnetic south pole], then they can interact maximally [it is called magnetic ‘reconnection’ – the two fields merge and particles can easily travel from one to the other] and we get ‘geomagnetic activity’, aurorae, ‘magnetic storms’, power line transformers burning out, etc, etc.
If the Earth dipole changes direction [which it might do perhaps a thousand years from now – it is a slow process taking decades of centuries to change] it will be positive Bz that creates activity, not negative Bz as now, but that is so far in the future that we do not need to worry about that yet.
Finally, Bz locally as ‘hitting’ the Earth changes sign over a time scale of a few hours. Over the last 24 hours, Bz has changed sign more than a dozen times. This does not give the interaction enough time to do its thing. Only when Bz goes negative for many hours do we get a strong interaction: a magnetic storm [also helped by the field strength being extra high and the solar wind extra fast – and so bringing a lot a field up to the Earth in a short time].
Here is a good site for the basics:
http://www.phy6.org/Education/Intro.html

leebert (19:30:56) :
Perhaps the slowing of the sunspot group poleward motion is the salient point, and whether it jibes with other observations. Hathaway’s statement was that the slowing of the sunspot groups is unprecedented.
What sets the pace in Dikpati’s model is the conveyor belt at depth, not at the surface, so the observation that the belt has slowed in recent years at the surface would not mean much. The model operates over a time frame of 20-40 years [they are bit coy as what the precise number is], so a few years of slowing ‘at the thin end’ would not seem to have much impact on the total ‘turn-around’ time]. The surface variation may not be representative for the whole belt. Personally, I have a problem with the conveyor belt motion. It is this: In their model Dikpati et al. got a very good agreement simulating the past 8 cycles or so, with the assumption that the conveyor belt moved at constant speed from one cycle to the next. When they tried different speeds from 2003 onwards they found that the predicted number was different. that was why they said that cycle 24 would be from ‘30% to 50%’ stronger. Now, in the past, some variation of the speed would have been expected [especially since we see one now], so the ‘predictions’ should have shown a similar variation over the past 8 cycles, partly destroying – or at least seriously lowering – the correlation between observed and simulated cycles.
As for the matter of decreased TSI of the past 16 years
I ask again, what decrease? It has decreased as much in those 16 years as it increased in the 16 years before that. TSI is now about what it was in 2008 – 2*16 = 1976.

Pamela Gray (21:09:38) :
What might be happening? That is quite a spike (actually two) on the lower graph!
Moscow does not show anything abnormal:
http://helios.izmiran.troitsk.ru/cosray/main.htm

Pam, Oulu is back, no alien attack this time.

statePoet1775 (14:04:51) :
2. Neutrons decay in about 15 minutes. So is this just measuring neutrons from the Sun?
Hey, Oulu is back to normal. The quiet Sun does not send out neutrons. Maybe it is not too fruitful to suspect highly improbable or impossible thing to happen every time there is the slightest little blip.