|
|
Post by lsvalgaard on Dec 28, 2010 19:12:13 GMT
Dr. Svalgaard, I've noticed that SOHO/SDO EUV imagery at the 171A wavelength is remarkable for its ability to render the magnetic field lines around the active regions. I thought maybe it had something to do with gyro-frequency emissions from accelerating charged particles spiraling along the field lines. But that's usually a much lower frequency, in the RF range I think. So, it seems to me this must be an atomic excitation property of the solar gases. Why does it seem to happen most clearly at 171A? What's going on? In the image one can clearly see the magnetic lines around 1137 and 1138. And I think (trying not to jump to an unwarranted conclusion) that I can see a few magnetic lines spewing out of the "old 1121" region, which is just emerging on the SE limb. Is there any way to estimate the magnetic field strength from the curvature of the lines? [SOHO EIT 171] The different wavelengths just reflect different temperatures and there just happens to be enough plasma at the temperature for 171 to show the structures clearly. We can compute the magnetic field up where the lines are from observations of the magnetic field in the photosphere below and check that the field lines come out right. Measuring the magnetic fields in the corona is hard [and hasn't been done yet in a convincing way]. See here for more www.aanda.org/articles/aa/abs/2010/03/aa12824-09/aa12824-09.html |
|
bradk
Level 3 Rank
Posts: 199
|
Post by bradk on Jan 8, 2011 14:58:21 GMT
Dr.-
I think you have predicted that if this is a gransd minimum, the radio and the sunspot numbers should diverge as the 10.7 will rise "normally" and the sunspot number will be low (as the spots are invisible because of the L&P effect)? Do I have this right, and if I do is it a concern for the model that the 10.7 and sunspot do seem to be tracking.
Thanks.
|
|
|
|
Post by lsvalgaard on Jan 8, 2011 16:01:43 GMT
Dr.- I think you have predicted that if this is a gransd minimum, the radio and the sunspot numbers should diverge as the 10.7 will rise "normally" and the sunspot number will be low (as the spots are invisible because of the L&P effect)? Do I have this right, and if I do is it a concern for the model that the 10.7 and sunspot do seem to be tracking. Thanks. The point is that they are not tracking. One way of seeing this is to take the formula for computing SSN from F10.7 that have worked well all the time from 1947 to 1990 and compute the SSN from observed values of F10.7. The ratio between the observed SSN and the computed SSN should then be the same at all times [namely 1.0] if SSN was tracking F10.7. This is what we get:  As you can see, there are now only half the sunspots we would expect. |
|
bradk
Level 3 Rank
Posts: 199
|
Post by bradk on Jan 8, 2011 16:32:05 GMT
Thanks, that is compelling. I was only looking at SC24 and thus thought both were lower than would be expected at this point in this solar cycle.
Any idea when L & P will publish again? Their theory and your addittions around solar minima are Nobel quality stuff!
|
|
|
|
Post by lsvalgaard on Jan 8, 2011 16:49:47 GMT
Thanks, that is compelling. I was only looking at SC24 and thus thought both were lower than would be expected at this point in this solar cycle. Any idea when L & P will publish again? Their theory and your addittions around solar minima are Nobel quality stuff! L&P send me their data every month. I think a good time to publish again would be 2015. Let the thing run its course. |
|
bradk
Level 3 Rank
Posts: 199
|
Post by bradk on Jan 13, 2011 0:41:40 GMT
Do I understand the 2015 date? Are you waiting for magnetism to drop below your magic "1500 Gauss" level to call a true grand minimum?
|
|
|
|
Post by lsvalgaard on Jan 13, 2011 5:38:54 GMT
Do I understand the 2015 date? Are you waiting for magnetism to drop below your magic "1500 Gauss" level to call a true grand minimum? something like that. Since this is unexplored territory it is even hard to know what to wait for. |
|
|
|
Post by rangertab1 on Jan 13, 2011 15:47:58 GMT
|
|
|
|
Post by lsvalgaard on Jan 13, 2011 16:11:37 GMT
Well, SC24 did start after all. Contributing to the Dalton cold were several major volcanic eruptions so we can't blame of the cooling on the Sun. Currently 2010 is near the top of warmest years; it seems hard to associate the all that warming with extremely low solar activity. So, personally I'm not impressed by the paper. |
|
bradk
Level 3 Rank
Posts: 199
|
Post by bradk on Jan 14, 2011 0:19:39 GMT
Dr.-
Isn't the opposite also true? We have had a very clear atmosphere over the last decade or so (since Pinatubo really), adding at least some to the current record temps, and most papers predict a lag of a decade or so between solar input drops and real temp drops. As you have noted, these changes are not huge. Am I just being silly or is there something there?
|
|
|
|
Post by lsvalgaard on Jan 14, 2011 2:33:57 GMT
Dr.- Isn't the opposite also true? We have had a very clear atmosphere over the last decade or so (since Pinatubo really), adding at least some to the current record temps, and most papers predict a lag of a decade or so between solar input drops and real temp drops. As you have noted, these changes are not huge. Am I just being silly or is there something there? that would also be true, but the effect is much too small to account fo the warming by itself. |
|
bradk
Level 3 Rank
Posts: 199
|
Post by bradk on Jan 14, 2011 7:23:58 GMT
Dr. Svalgaard-
I am likely just showing my ignorance here, so I appreciate your indulgence. I have looked at your powerpoints on the topic, I believe titled "Does the sun vary enough?" and truly appreciate your posting them. Recent papers point to a 0.2 to 0.3 degree effect from the clarity of the atmosphere, as you say not nearly enough. That said, if the solar output varies, namely long and short wavelength changes vary significantly, could that change your your analysis any? Recent data from SORCE does show a significant change in UV over the solar cycle (and it is so unexpected as to be controversial).
|
|
|
|
Post by lsvalgaard on Jan 14, 2011 20:52:01 GMT
Dr. Svalgaard- I am likely just showing my ignorance here, so I appreciate your indulgence. I have looked at your powerpoints on the topic, I believe titled "Does the sun vary enough?" and truly appreciate your posting them. Recent papers point to a 0.2 to 0.3 degree effect from the clarity of the atmosphere, as you say not nearly enough. That said, if the solar output varies, namely long and short wavelength changes vary significantly, could that change your your analysis any? Recent data from SORCE does show a significant change in UV over the solar cycle (and it is so unexpected as to be controversial). Since the UV is offset by the opposite change in Infrared, climate modeling show that the net effect is small, e.g. lasp.colorado.edu/sorce/news/2010ScienceMeeting/doc/Session4/4.04_Cahalan_atmos_model.pdf"Direct Responses to SIM-based Alternative Forcing Scenario 1. NUV in phase with TSI, larger amplitude, explains observed ~1 K amplitude @40 km. 2. VIS and NIR out of phase with TSI. ยป TSI, the integral over the spectrum, comprised of spectral bands with compensating effects. 3. Surface radiative forcing very small, direct surface response < 0.1 K in 11-year |
|
bradk
Level 3 Rank
Posts: 199
|
Post by bradk on Jan 15, 2011 13:10:15 GMT
I think I am moving beyond the topics of this board, but I will just put it out there and not expect a response - although the surface forcing seems nearly identical, I expect the penetratrance, the atmospheric absorption, ionization caused thereby and even the cloud forming ability may differ enough to drive more change than the forcing alone, and these may differ even more in an atmosphere with volcanic particles than a clear one - but that is a climate model question.
|
|
|
|
Post by france on Jan 17, 2011 22:42:21 GMT
Well, SC24 did start after all. Contributing to the Dalton cold were several major volcanic eruptions so we can't blame of the cooling on the Sun. Currently 2010 is near the top of warmest years; it seems hard to associate the all that warming with extremely low solar activity. So, personally I'm not impressed by the paper. Hello Dr Svalgaard, best wishes for 2011. 2010 is globaly one of the warmest year but in North of Europe we had a harsh winter 2009 and 2010. In last december , several records of cold happened. In UK it was the worse since 1910 decade, idem in Norway... and if I'm not wrong snow is fell down in sunny California. In april 2010 a volcanic eruption in Finland made a big disturbance in air plane traffic during several weeks. And snow and ice made the same just before hollidays departures in december in France. The north of the country was blocked by high snowdrift as it normally the case in Canada where at the opposite weather was very mild. Too much snow on soil made an important flooding in north of France and other countries of north of Europe when rise in temperture arrived with heavy rainfall... an other volcanic eruption with a lot of earthquakes around the region were recorded in Anak Krakataua the son of the dangerous Krakataua which made temperatures cooler all over the world last time it was in activity... I wanted to show you this paper to know if you already studied it www.springerlink.com/content/h623h560n0m48q65 |
|
