July 2004 Solar Flux Rebounds to 1185

[donsutherland1]

In July, the solar flux rebounded to 1185 after having fallen to 974 in June.

So far, through 2004, the flux has been closest to that of 1961:

Year.........Jan...........Feb..........Mar...........Apr..........May..........Jun...................July
2004........1141.........1070.......1120.........1012........998............974................1185
1961........1220.........1064.......1048.........1050........993..........1099................1165

Average difference: 49.3

Given the latest trend, it appears that the Winter 2004-05 (December 2004 through March 2005) solar flux will average in the vicinity of 900-1000 vs. last winter's 1125 average. This is somewhat higher than my earlier expectation of 820-920. However, continued fluctuations could change this further. Whether or not the strong rise in July suggests a temporary sustained rise in the solar flux remains to be seen.

[USAwx1]

Good post, and nice catch, but IMO your reading too much into it, Don. If you go back and check out the data set you will find that there were many 12-24 month periods similar to this WRT the ups and downs in 10.7cm radio flux --- particularly following the solar maximum of the 11 year cycle.

Below are a few examples:

2003 1440 1245 1322 1263 1162 1293 1277 1221 1122 1513 1408 1150
2004 1141 1070 1120 1012 998 974 1185 -999 -999 -999 -999 -999

1950 1507 1433 1378 1643 1571 1287 1341 1209 986 999 1019 1011
1951 1079 1019 1025 1271 1686 1617 1163 1098 1178 1060 1044 1024

1961 1220 1064 1048 1050 993 1099 1165 1062 1127 967 903 948
1962 949 1022 1003 962 979 910 807 773 895 878 849 820

1972 1148 1418 1285 1129 1296 1354 1220 1257 1136 1211 1016 1029
1973 1022 987 1004 1050 970 912 845 829 1056 877 815 842

1983 1423 1226 1186 1189 1371 1386 1250 1244 1090 1124 925 934
1984 1161 1406 1220 1287 1283 1003 893 837 781 735 763 759

1993 1210 1426 1364 1159 1124 1093 990 937 870 1003 959 1048
1994 1150 996 904 791 799 773 805 761 790 877 809 774

You will notice that this has taken place during the 1st-4th year of each decade back to the 1950s. IMO it’s just a normal cyclical tendency in the sun’s activity when trending down from the solar maximum and not a secondary or even for that matter 3rd peak in activity for this cycle.

Activity trended down quite substantially thereafter which you can see quite clearly in the years following those above in the data set.

If any years were to be “analogs” per se for solar activity it would be those listed above since they displayed similarly high variability in 10.7cm radio flux levels.

The striking similarity in activity between the first through the fourth year of each decade since the 1950s is not just a freak thing, but at the same rate there is nothing to read into it. The reason for that similarity is just those years happened to fall at a the same spot in the solar cycle following the maximum –-- and because each cycle lasts NORMALLY a little longer than a decade (11 years) you can see why this pattern is repetitive.

ANYWAY getting back to the short term. The reason for the Jump in monthly values is the result of recent flare-ups.



At the same time there was also a corresponding SHARP jump in geomagnetic activity (As evidenced by Planetary A-index values). This is common for our current position in the solar cycle. also remember that the effect of the radio flux is MAXIMIZED over the sub-tropics and mid-latitudes --- while the effects of geomagnetic action are more important over the polar regions and arctic.

These ups and downs will be possible through the remainder of the year, the effects of which however should NOT be significant enough to disrupt specific global teleconnection patterns (AO, NAO, intensity of the Aleutian low etc… (Which BTW has already been anomalously strong for summer)

Useful links:

http://www.cdc.noaa.gov/correlation/solar.data/
http://www.sec.noaa.gov/
http://www.dxlc.com/solar/

[donsutherland1]

USAwx1,

I agree that the overall downward cycle continues and that there are periodic fluctuations. I will be interested in seeing if another secondary peak develops.

One possible development of interest toward that end is that Sunspot 649, the one that generated a number of X-class flares in July, has returned to the near side of the sun and is expanding in size:

<img src="http://www.spaceweather.com/images2004/09aug04/649_strip.gif">

It's the spot visible on the left side of the above animation.

Finally, I agree with you that the fluctuations likely won't be significant enough to alter the global teleconnection patterns for the winter. Certainly, the impact of an 820-920 average vs. a 900-1000 average is almost certainly insignificant.

[USAwx1]

USAwx1,

I agree that the overall downward cycle continues and that there are periodic fluctuations. I will be interested in seeing if another secondary peak develops.

One possible development of interest toward that end is that Sunspot 649, the one that generated a number of X-class flares in July, has returned to the near side of the sun and is expanding in size:

<img src="http://www.spaceweather.com/images2004/09aug04/649_strip.gif">

It's the spot visible on the left side of the above animation.

Finally, I agree with you that the fluctuations likely won't be significant enough to alter the global teleconnection patterns for the winter. Certainly, the impact of an 820-920 average vs. a 900-1000 average is almost certainly insignificant.

Technically you could say that the 2001-02 upsurge was a secondary maximum for SC#23. A third would practically be unprecedented for any cycle but the values must remain continue to increase and remain high (say the 1500-2000 range) for the next several months. I don’t foresee that happening. It is possible though that SC#23 will last LONGER than several of the previous cycles eventhough SC#23 was NOT as intense as others and perhaps longer than the 11 year mean.



Solar cycle 21 lasted 10 years and three months --- SC#22 only lasted 9 years and 8 months. Both shorter than the normal 11 years.



http://www.dxlc.com/solar/cycl1_20.html

We went through a similar episode last October and November, and I suspect this current upsurge in activity will quickly decrease.

Actually the X-6 flare produced a huge CME (you can see how the corresponding proton storm affected the image resolution) that was responsible for the upsurge in geomagnetic activity shortly thereafter.

[USAwx1]

BTW if my first post sounded a bit harsh...I apologize it was not intended to be.

[donsutherland1]

USAwx1,

Thanks for this great information. Also, I didn't find anything harsh about your first reply. It was informative.

Best wishes.