Solar activity and it's influence on climate

Andre

A very informative study of eminence grise Cees de Jager. If you think it's too old, check that Silvia Duhau and Dirk Callebaut are credited for their support.

Anyway in the abstract:

Xnn

The part of the article where the basis for forecasting solar cycle 24 is fairly interesting: should max out with about 68 sunspots in 2014. That is outside of the consensus view, but also consistent in that the later it starts, the smaller the peak number of sunspots will be. NOAA has given a peak range between 80-140 sunspots sometime between 2012-2013:

http://www.swpc.noaa.gov/SolarCycle/

However, then the article goes on to predicts the earth's temperature based on a relationship between sunspots, geomagnetic field strength and the number of years since 1600:

T = 0.5*(sunspots) + 0.33*(geomagnetic field)+ C(years since 1600).

In other words the paper is predicting a cyclic temperature (due to oscillating parameters of the sun) along with a constantly warming earth. That is an incredibly simple view of the earth’s climate, but since CO2 and CH4 levels have been increasing and warming the earth for most of that time, it is not too surprising.

Of course, such an equation is foolish since there is no reason to suspect that the earth will warm indefinately.

Gokul43201

But it is not outside the range of several other predictions.

To me the prediction of cycle 24 is probably among the more exciting of the ... shall we call them "model wars"? What makes for the excitement is:

(i) the relatively short time frame for observational support/falsification (roughly the next 3-5 years),
(ii) large differences between the predictions of the two major sets of groups.

For instance, on the one side, Jager et al[1] predict an R_z for cycle 24 of 68+/-15. Using their dynamo model, Svaalgard et al[2] predict 75+/-8 and Schatten[3] predicts 80+/-30 using a precursor field method. Choudhuri (et al) [4a,b] predict a peak of about 75, and like Svaalgard, is quite vocal in asserting that the model of Dikpati et al[5], in the high R_max camp, is very wrong.

On the other hand, Hathaway and Wilson[6] predict an amplitude of 160+/-30 using the method of Joan Feyman based on a correlation with geomagnetic activity. This is very close to the dynamo model prediction by Dikpati et al[5] of 165+/-15. Using a different method based on the drift rate of sunspot zones[7], Hathaway et al arrive at 145+/-30.

So the two sides are separated by a significantly large gap. But it looks like NOAA/SWPC happen to exactly fill this gap with their prediction of 115+/-25[8]. Also, in this gap are a few others, like Kane[9] and Wang et al[10].

The only group I know of that is making a prediction of R_z < 50 is Badalyan et al[11].

References:

1. C de. Jager, [i]Neth. J. Geosci.[i] 87, 207 (2008) [PDF]
2. L. Svaalgard et al, Geophys. Res. Lett. 32, L01104 (2005) [PDF]
3. K. Schatten Geophys. Res. Lett. 32, L21106 (2005)
4a. A. R. Choudhuri, J. Astrophys. Astr. 29, 41 (2008) [PDF]
4b. A. R. Choudhuri, et al, Phys. Rev. Lett. 98, 131103 (2007)
5. M. Dikpati et al, Geophys. Res. Lett. 33, L05102 (2006)
6. D. H. Hathaway and R. M. Wilson, Geophys. Res. Lett. 33, L18101 (2006) [PDF]
7. D. H. Hathaway et al, Astrophys. J. 589 665 (2006). [Paper, erratum]
8. http://www.swpc.noaa.gov/SolarCycle/
9. R. P. Kane, Solar Physics 189, 217 (1999)
10. J. -L. Wang et al, Chin. J. Astr. Astrophys. 2, 557 (2002)
11. O. G. Badalyan Solar Physics 199, 421 (2001)

Xnn

At the bottom is the latest image from SOHO and recent TSI cycles from GISS/NASA/Frochlich & Lean.

There were some sun spots earlier, but they are now gone. However, notice that at around 10:00 and 2:30 some focula are still visable. These are basically what is left over from earlier sunspots. Not sure how long they last, but my understanding is that they are what turns the spectrum more towards the ultraviolet and also increases total irradiance.

Anyhow, it looks like the next cycle has finally started. Since it is so late, I believe that tends to favor the lower predictions. Indeed, just looking at the irradiance chart from NASA and my intunition tells me the next cycle will be about half of the last one. That the experts are all over the place, suggests that just about anybodys guess is as good as another.


From NASA GISS: http://data.giss.nasa.gov/gistemp/2008/

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Gokul43201

Does it? I thought a lower R_z for a given cycle is correlated with a large time from start to peak for the same cycle (not the time from the previous peak to the start of the specified cycle).

Xnn

http://www.swpc.noaa.gov/SolarCycle/...ssRelease.html

I've interpreted this as meaning the later Cycle 24 appears, the weaker the forecast (at least according to the strong-cycle group).

Bored Wombat

Looking at the graph 10, I would disagree that the current warming is unexceptional. Even though it is only marginally the most warming above what is predicted by solar forcing alone, the annual change at similar points was slow, as the turning point approached.

The annual change seems to be accelerating since about 2000, and doesn't look like turning soon at all.

Mammo

I second this opinion.

Skyhunter

I believe that both are used for prediction.

The longest period from maximum to minimum for the numbered cycles I believe was cycle 1 to cycle 2. Which preceeded the Dalton minimum.