Solar Terrestrial Activity Report

Last major update issued on November 21, 2011 at 03:45 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-24 (last update November 1, 2011)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update November 1, 2011)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update November 1, 2011)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update November 2, 2011)]

[POES auroral activity level since October 2009 - updated November 18, 2011]
Annotated geomagnetic activity charts - Carrington rotation 2114 [August-September 2011] - 2115 [September-October 2011]
[Solar polar fields vs solar cycles - updated June 27, 2011]

Recent activity

The geomagnetic field was very quiet on November 20. Solar wind speed ranged between 270 and 345 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 139.9 (decreasing 5.4 over the last solar rotation). The planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 1.6). Three hour interval K indices: 00000111 (planetary), 00001111 (Boulder).

The background x-ray flux is at the class B6 level.

At midnight UTC the visible solar disk had 9 spotted regions (in 2K resolution SDO images).

Region 11346 [S17W41] decayed slowly and quietly.
Region 11350 [N29W10] was quiet and stable.
Region 11352 [S23E15] decayed slowly and was quiet.
Region 11353 [N08E33] decayed slowly and quietly.
Region 11354 [S14E32] was fairly active during the day and lost a few spots and some penumbral area. Flares: C2.1 at 06:26, C4.8 at 07:41, C3.0/1F at 11:55, C1.0 at 16:15, C6.1/1F at 16:47 UTC
Region 11355 [N15E47] added some penumbral area and was quiet.
Region 11356 [N16E70] rotated fully into view revealing a magnetic delta structure in a central penumbra. An M class flare is possible. Flare: C1.8 at 13:32 UTC
New region 11357 [N19W17] emerged in the northeast quadrant on Nov.17 and was numbered by SWPC 3 days later. Currently it appears as if the region should be split as there are two sets of spots and magnetic fields. Flare: C1.8 at 07:22 UTC

Spotted regions not reported by NOAA/SWPC:
[S1333] emerged in the northeast quadrant on November 19. Location at midnight: N12E22

Coronal mass ejections (CMEs)

November 18-20: No obviously Earth directed CMEs observed.

Coronal holes

Coronal hole history (since late October 2002)
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago

A poorly defined trans equatorial coronal hole (CH485) was in an Earth facing position on November 19-20.

The above coronal hole map is based on a new method where coronal holes are detected automatically. The method may need some fine tuning, however, it has significant advantages over detecting coronal holes manually. The main improvement is the ability to detect coronal holes at and just beyond the solar limbs. Early results using this method for SDO images over a span of several weeks indicate a good match between coronal holes observed over the visible disk and their extent and position at the east and west limbs. Note that the polar coronal holes are easily detected using the new method, the extent and intensity of both holes are consistent with other data sources.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is good. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet on November 21. On Nov.22-23 there's a chance of unsettled intervals due to effects from CH485.

Coronal holes (1) Coronal mass ejections (2) M and X class flares (3)

 

1) Effects from a coronal hole could reach Earth within the next 5 days. When the high speed stream has arrived the color changes to green.
2) Effects from a CME are likely to be observed at Earth within 96 hours.
3) There is a possibility of either M or X class flares within the next 48 hours.

Green: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% probability.

Active solar regions

Click on image for higher resolution image) Compare to the previous day's image

When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue (blue-green) is positive.

Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC. Comments are my own, as is the STAR spot count (spots observed at or inside a few hours before midnight) and data for regions not numbered by SWPC or where SWPC has observed no spots. SWPC active region numbers in the table below and in the active region map above are the historic SWPC/USAF numbers.

Active region Date numbered
detected
Spot count Location at midnight Area Classification SDO / HMI 4K continuum
image with magnetic polarity overlay
Comment
SWPC STAR SDO SWPC STAR Current Previous
11346 2011.11.11
2011.11.12
3 10 S18W44 0040 CSO CAO

location: S17W41

11347 2011.11.12
2011.11.13
    N06W50           spotless
S1322 2011.11.13     N10W33           plage
S1323 2011.11.13     N20W53           plage
11349 2011.11.14     N15W81           plage
11350 2011.11.14   1 N25W11 0000   AXX location: N29W10
11351 2011.11.14     S24W31           region should be deleted, was the trailing spots of region 11346
11352 2011.11.15
2011.11.16
7 11 S25E15 0120 DSO CSO

 

S1327 2011.11.16     S25W02         plage
11354 2011.11.16
2011.11.17
12 27 S17E30 0220 DAI DAI beta-gamma

location: S14E32

11353 2011.11.16
2011.11.17
2 6 N07E32 0020 HSX HRX location: N08E33
11355 2011.11.17
2011.11.18
1 9 N14E44 0090 HSX CAO location: N15E47

area: 0250

11357 2011.11.17
2011.11.20
5 10 N17W18 0020 DRO CRO location: N19W17
S1332 2011.11.18     N24E51         plage
11356 2011.11.19 1 7 N14E63 0110 HSX DSO beta-gamma-delta

area: 0450

location: N16E70

S1333 2011.11.19   6 N12E22 0000   BXO  
S1334 2011.11.19     N18E06         plage
Total spot count: 31 87  
Sunspot number: 101 177  (total spot count + 10 * number of spotted regions)
Classification adjusted SN: 64 118  (Sum of total spot count + classification adjustment for each AR. Classification adjustment: X=0, R=3, A/S=5, H/K=10)
Relative sunspot number (Wolf number): 61 80  k * (sunspot number). k = 0.6 for SWPC. k = 0.45 (changed from 0.33 on Nov.1) for STAR SDO

Monthly solar cycle data

Month Average measured solar flux International sunspot number (SIDC) Smoothed sunspot number Average ap
(3)
2008.07 65.7 (SF minimum) 0.5 2.8 (-0.4)  
2008.12 69.2 0.8 1.7 (-)
sunspot minimum
3.25
2010.07 79.8 16.1 16.7 (+0.3) 6.31 / 5.15
2010.08 79.2 19.6 17.4 (+0.7) 8.49 / 7.77
2010.09 81.1 25.2 19.6 (+2.2) 5.33 / 5.45
2010.10 81.6 23.5 23.2 (+3.6) 6.07 / 6.27
2010.11 82.5 21.5 26.5 (+3.3) 4.80 / 5.50
2010.12 84.2 14.4 28.8 (+2.3) 3.41 / 4.35
2011.01 83.6 19.1 31.0 (+2.2) 4.32 / 5.51
2011.02 94.6 29.4 33.4 (+2.4) 5.41 / 6.44
2011.03 115.0 56.2 36.9 (+3.5) 7.79 / 8.18
2011.04 112.6 54.4 41.8 (+4.9) 9.71 / 8.83
2011.05 95.8 41.6 (47.4 predicted, +5.6) 9.18 / 8.94
2011.06 95.8 37.0 (52.5 predicted, +5.1) 8.96 / 8.06
2011.07 94.2 43.9 (58.2 predicted, +5.7) 9.14 / 8.16
2011.08 101.7 50.6 (63.7 predicted, +5.5) 8.16 / 7.26
2011.09 133.8 78.0 (67.0 predicted, +3.3) 12.80 / 12.27
2011.10 137.3 88.0 (70.5 predicted, +3.5) 7.52
2011.11  160.9 (1) 92.2 (2A) / 138.3 (2B) (74.9 predicted, +4.4) (4.05)

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz.
2A) Current impact on the monthly sunspot number based on the Boulder (NOAA/SWPC) sunspot number (accumulated daily sunspots / month days). The official SIDC international sunspot number is typically 30-50% lower. 2B) Month average to date.
3) Running average based on the preliminary daily SWPC ap indices. Values in red are based on the official NGDC ap indices.

This report has been prepared by Jan Alvestad. It is based on analysis of data from whatever sources are available at the time the report is prepared. All time references are to the UTC day. Comments and suggestions are always welcome.

SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.