It has been awhile since I’ve looked at the Ap Index. The last time was April of 2009.
From the data provided by NOAA’s Space Weather Prediction Center (SWPC) you can see just how little Ap magnetic activity there has been since. Here’s my graph from September 2009 SWPC Ap data:
For a longer perspective, David Archibald, has a graph of the Ap Index back to 1932. The solar average geomagnetic planetary index, in Dec 2008, Ap was at its lowest level in 75 years:
Click for a larger image – I’ve added some annotation to the graph provided by Archibald to point out areas of interest and to clarify some aspects of it for the novice reader.
The last time the Ap index was this low was 1933. The December 2008 Ap value of 2,, has never been this low. (Note: Leif Svalgaard contends this value is erroneous, and that 4.2 is the correct value – either way, it is still lower than 1933) Further, the trend from October 2005 continues to remain low, though some signs of a slight rebound are showing.
This Ap index is a proxy that tells us that the sun is now quite inactive, and the other indices of sunspot index and 10.7 radio flux also confirm this. The sun is in a full blown funk, and your guess is as good as mine as to when it might pull out of it. So far, predictions by NOAA’s SWPC and NASA’s Hathaway have not been near the reality that is being measured.
As Leif Svalgaard points out, Ap is just one of several indices that describe geomagnetic activity. There are several others [aa, am, IHV, …] that go much further back in time [to the 1840s]. You can get more info from:
http://www.leif.org/research/IAGA2008LS.pdf and
http://www.leif.org/research/Seminar-UCLA-ESS288.pdf
For those that follow the sunspot number (SSN) I’ve graphed the Ap and SSN together. As you can see, we’ve been in a reduced state of solar activity now for quite some time. It has been almost 4 years since the prominent drop in Ap in October 2005. SSN mirrors the decline of the Ap index since then.
As many regular readers know, I’ve pointed out several times the incident of the abrupt and sustained lowering of the Ap Index which occurred in October 2005. The abrupt step change seemed (to me) to be out of place with the data, and since then the data seems less “active”, with reduced amplitudes. And then we have the fact that the sun seems to have reestablished at a lower plateau of the Ap index after that October 2005 step change and has not recovered now in almost 4 years. It seems to me to be a noteworthy event.
UPDATE: Thanks to Leif Svalgaard, we have a more extensive and “official” Ap dataset (NOAA’s SWPC has issues, see comments) that I’ve plotted below. The step change in October 2005 is still visible and the value of 3.9 that occurred in April of this year is the lowest for the entire dataset.
And I’ve also plotted the 1991 to present data from BGS/Svalgaard to compare against the NOAA SWPC data:
Invariant (00:14:59) “we may argue that increased cloud coverage may lead to reduced Qin, but possibly also to reduced Qout since more clouds may have an insulating effect.”
This gets interesting when you take into consideration (average) diurnal cloud variations. Topography is not irrelevant. Locally (coastal, mountainous area), I also find a seasonal variation in temperature range relations with solar variables (which is hardly surprising …but how many studies mention this?…) The region I’m in (Pacific NorthWest N.America) has heavy seasonal precipitation patterns that relate well to ENSO after adjusting for solar cycles. I’m not suggesting the relations are straightforward, but I am suggesting they are non-random.
Tenuc (23:56:22) : Some energy is being radiated into space quickly, some becomes trapped over long time periods and some is permanently retained as a result of chemical processes.
Possibly climate scientists should regularly read the good old paper by Lorenz (1963)
http://www.cc.uoa.gr/~pji/nonlin/lorenz.pdf
A model with a billion highly nonlinear and sensitive differential equations [our climate] has many different regimes, limit cycles and feedback mechanisms. My understanding of nonlinear dynamics is that our intuition may sometimes guide us in the correct direction and sometimes lead to erroneous conclusion. For example, increasing a variable gradually may at first lead to expected dynamics going one way, but suddenly a threshold is exceeded and we encounter unexpected dynamics going the opposite way. For most people this may be difficult to understand, because it means [not literally] that in nonlinear dynamics usually 1+1 = 2 but sometimes [after a threshold is exceeded] 1 + 1 may be -42.
Invariant(00:14:59) “but possibly also to reduced Qout”
The water vapor and cloud mechanism is probably not well understood.
A slight increase in solar radiation will give more water vapor(positive feedback) followed by more cloud formation(minor negative feedback in the eqautorial zone) and especially in the polar regions more cloud cover(positive feedback – less Qout) more snow.
poslednieje (04:38:56) : The water vapor and cloud mechanism is probably not well understood.
Agreed. See my previous post Invariant (04:13:05) .
maksimovich (00:08:36) :
I was suggesting that changes in the density of the ISM (not the passage through shells etc) can be expected on shorter timescales 10^3-10^5 years eg Muller et al.
The density changes because we move through the clump, cloud, shell, whatever… So I’m afraid I’m not sure what you mean…
I believe he is saying, Lief, that the clump/cloud/shell is non-uniform.
We should expect, in addition to clouds of different overall density, laminations/filaments of varying thickness and density within any cloud. We are in a spiral galaxy, not an elliptical, where stratification and classification are the norm rather than the exception. Messier 0 is a wildly exotic place close up.
rbateman (22:27:05) :
I believe he is saying, Lief, that the clump/cloud/shell is non-uniform.
The observed agreement between the strength of the Earth’s magnetic magnetic variation over the past 12,000 years and the cosmic ray intensity [14C] argues for no additional modulation from passing through clumps, etc [spiral galaxy or not].
Invariant (04:13:05) “A model with a billion highly nonlinear and sensitive differential equations [our climate] has many different regimes, limit cycles and feedback mechanisms. My understanding of nonlinear dynamics is that our intuition may sometimes guide us in the correct direction and sometimes lead to erroneous conclusion. For example, increasing a variable gradually may at first lead to expected dynamics going one way, but suddenly a threshold is exceeded and we encounter unexpected dynamics going the opposite way. For most people this may be difficult to understand, because it means [not literally] that in nonlinear dynamics usually 1+1 = 2 but sometimes [after a threshold is exceeded] 1 + 1 may be -42.”
The problem is that it is not covered in the (mainstream) education system. The excessively-linear mainstream thinking in our society is a severe limiting factor in our development. People who think conditionally have a fairly restricted audience. Meanwhile those gripped by notions of (untenable) univariate linear extrapolation keep raking in funding. Even if the necessary reforms to the education system start soon, the payoff may not be realized until more than a century from now. Thus, it will be very difficult to secure the support of the majority who are focused mainly on surviving the day &/or decade. For other societies, there is a clear path upon which to run right past us.
Leif Svalgaard (04:21:07) :
14C has reported problems being a proxy for cosmic ray intensity.
So, this is a fuzzy argument that defies the structure of a spiral galaxy.
If this is true, it means the cosmic rays cannot have originated in the Milky Way. Black holes in it’s core are out, as they have been observed to exhaust present fuel, awaiting a further victim to haplessly wander too close.
The Sun stands alone as master of it’s domain.
Leaves only the Big Bang as GCR source.
BBCR’s.
“The excessively-linear mainstream thinking in our society is a severe limiting factor in our development.”
May I nominate for QoW??
Sandy (18:19:10) “May I nominate for QoW??”
as long as you acknowledge the emphasis I placed on “severe” ….but I’ve seen quite a few good quotes this week (as is – fortunately – the norm around here)
rbateman (17:52:07) :
If this is true, it means the cosmic rays cannot have originated in the Milky Way.
I think there is general agreement that most GCRs originate in our Galaxy.
Sandy (18:19:10) :
“The excessively-linear mainstream thinking in our society is a severe limiting factor in our development.”
There are two approaches [and possibly all shades in between]:
(1) an orderly, logical, linear thinking that progresses from solid result to solid result, building on past success and findings
(2) a scatter-brained, kitchen-sink, chaotic, intuition-based jumping from loose idea to unsubstantiated speculation and conclusions and back
I would prefer (1) over (2) any time. The rare, intuitive, out-of-the- box thinking necessary for breakthrough progress is not hampered by (1) [paratus mens mentis fortuna gratia est], but drowns in junk with (2).