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Post by Bob k6tr on Mar 4, 2010 20:30:35 GMT
That depends on whether or not you see less contrast as "going up" or not. A contrast of 1 means that there is no contrast, so sunspots would be invisible. To most folks, such a situation would imply a lack of contrast, or actually no contrast at all. So as the contrast goes up toward 1, it is decreasing. If sunspots are becoming "more contrasty" then they would not be going away... Well there seems to be an incomplete understanding of terms here. A sunspot is composed of two parts. The Dark Magnetic Core which is but a small fraction of the Spot and the surrounding bright spot known as the facula. The facula is most easily seen in the 284A Photo and to a lesser extent in the 304A Photo. Now the question is what is Livingston referring to when he means "contrast" ? Is he talking about the contrast of the spot relative to the backround level of the whole disk ? Or is he referring the contrast of the spot relative to the immediate area around it's periphery ? If it's the latter and Livingston is saying spot megnetism is declining while contrast is increasing. Thus implying the intensity of the facula is increasing. Leif, I know I have asked you about this before. Could we trouble you for clarification ? |
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Post by sranderson on Mar 4, 2010 22:02:11 GMT
I just read the old Livingston Penn paper again. They say they are measuring the "Continuum intensity of the umbral spectra, normalized to the intensity of the nearby quiet Sun." This is the measurement that is going up. So basically, zero would be no measurable emission, and 1 would be emission that is the same as that of the "nearby quiet Sun". If the umbral intensity is 1, the sunspot would not be visible.
I probably messed up by using the term "contrast" (which goes down as the umbral intensity goes up).
Scott
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Post by lsvalgaard on Mar 5, 2010 4:04:20 GMT
I just read the old Livingston Penn paper again. They say they are measuring the "Continuum intensity of the umbral spectra, normalized to the intensity of the nearby quiet Sun." This is the measurement that is going up. So basically, zero would be no measurable emission, and 1 would be emission that is the same as that of the "nearby quiet Sun". If the umbral intensity is 1, the sunspot would not be visible. I probably messed up by using the term "contrast" (which goes down as the umbral intensity goes up). Scott this is the correct interpretation. |
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Post by sranderson on Mar 9, 2010 19:17:22 GMT
It appears that the latest measurements shown on the most recent graph were taken in early January. Does anyone know if L&P have taken any measurements since that time? It would seem that the spurt of sunspots in the last 6-8 weeks would have been a good test of whether or not the trend seen since 1990 is continuing in the uptick of the new cycle.
Also, are there any other researchers attempting to duplicate L&P's measurements?
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Post by George Kominiak on Mar 10, 2010 3:38:28 GMT
It appears that the latest measurements shown on the most recent graph were taken in early January. Does anyone know if L&P have taken any measurements since that time? It would seem that the spurt of sunspots in the last 6-8 weeks would have been a good test of whether or not the trend seen since 1990 is continuing in the uptick of the new cycle. Also, are there any other researchers attempting to duplicate L&P's measurements? Hey! The weather in Arizona has been rather lousy for telescope viewing and it looks like there's more clouds on the way. I'll bet that there aren't any other researchers looking into this question because it might be a bit "old fashioned," not to mention labor intensive!! Not only that, their results seem to suggest something that doesn't fit the predictions of current modeling efforts. G. |
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hank
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Post by hank on Mar 19, 2010 19:44:45 GMT
Leif, is this data collection still at the early stage of trying to figure out how much natural variability there is, or is there enough collected that it's possible to figure out a statistical test for the likelihood of a trend?
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Post by lsvalgaard on Mar 20, 2010 8:22:02 GMT
It appears that the latest measurements shown on the most recent graph were taken in early January. Does anyone know if L&P have taken any measurements since that time? It would seem that the spurt of sunspots in the last 6-8 weeks would have been a good test of whether or not the trend seen since 1990 is continuing in the uptick of the new cycle. Also, are there any other researchers attempting to duplicate L&P's measurements? Latest data Feb 25-26 |
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Post by lsvalgaard on Mar 20, 2010 8:23:29 GMT
Leif, is this data collection still at the early stage of trying to figure out how much natural variability there is, or is there enough collected that it's possible to figure out a statistical test for the likelihood of a trend? No, Bill Livingston observes whenever he has telescope time and the weather permits [has been bad in Arizona this winter. |
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Post by sranderson on Mar 20, 2010 17:15:17 GMT
Do you happen to know if the Feb 25-26 data was consistent with the observed trend? Back in September, you had a txt file with all of the data to date. Is it possible to get an update of that? Thanks. |
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Post by lsvalgaard on Mar 20, 2010 18:17:04 GMT
Do you happen to know if the Feb 25-26 data was consistent with the observed trend? Back in September, you had a txt file with all of the data to date. Is it possible to get an update of that? Thanks. Very consistent:  www.leif.org/research/Livingston.txt |
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Post by sranderson on Mar 21, 2010 2:13:09 GMT
Thank you very much Dr. Svalgaard. The continued decline is quite interesting. This is a big deal indeed. The mechanism behind it all however seems to be completely unknown. While we have learned much about the sun, there is so much more that we just don't understand yet. I guess that is why it is so interesting -- a frontier where we can still make fundamental discoveries.
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clive
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Post by clive on Mar 21, 2010 5:08:23 GMT
The method of data collection is dubious. 2 sunspot groups were measured over Jan/Feb when we have experienced quite high activity compared to last year. The major active regions have not been measured (1040,1045 etc). The last measurement was taken during speck activity.
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radun
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Post by radun on Mar 21, 2010 14:30:57 GMT
The method of data collection is dubious. 2 sunspot groups were measured over Jan/Feb when we have experienced quite high activity compared to last year. The major active regions have not been measured (1040,1045 etc). The last measurement was taken during speck activity. You may well be correct. Vukcevic put up this comment on WUWT , I think he may have a point. vukcevic (16:28:06) :
OT . Latest Livingston solar observations data are available (Dr. Svalgaard’s file). Although general trend lines appear to be there, but since the contrast and magnetic field critical limits appear to be intact, whole process of the ‘sunspot dimming’ appear to be uncertain. |
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Post by lsvalgaard on Mar 21, 2010 15:29:43 GMT
The method of data collection is dubious. 2 sunspot groups were measured over Jan/Feb when we have experienced quite high activity compared to last year. The major active regions have not been measured (1040,1045 etc). The last measurement was taken during speck activity. The method is unbiased. It works like this: Bill has fixed slots with telescope time decided months ago. If the weather permits, he observes all spots visible, specks or monsters alike during his slot. So the method is not dubious. With increasing activity and better weather [as we move towards summer] we should get a fuller measure. |
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Post by lsvalgaard on Mar 21, 2010 15:31:32 GMT
The method of data collection is dubious. 2 sunspot groups were measured over Jan/Feb when we have experienced quite high activity compared to last year. The major active regions have not been measured (1040,1045 etc). The last measurement was taken during speck activity. You may well be correct. Vukcevic put up this comment on WUWT , I think he may have a point. vukcevic (16:28:06) :
OT . Latest Livingston solar observations data are available (Dr. Svalgaard’s file). Although general trend lines appear to be there, but since the contrast and magnetic field critical limits appear to be intact, whole process of the ‘sunspot dimming’ appear to be uncertain.the graph should start in 2001, not 2004. We have reasonable coverage since 2001. This is typical of Vuk's standard cherry picking. |
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