Solar Terrestrial Activity Report

Last major update issued on November 18, 2011 at 05:25 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 16, 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 quiet on November 17. Solar wind speed ranged between 376 and 475 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 147.7 (decreasing 20.1 over the last solar rotation). The planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 2.8). Three hour interval K indices: 00201011 (planetary), 01311211 (Boulder).

The background x-ray flux is at the class C2 level.

At midnight UTC the visible solar disk had 12 spotted regions (in 2K resolution SDO images).

Region 11341 [N10W80] decayed slowly and quietly.
Region 11342 [N16W86] was quiet and stable.
Region 11343 [N29W65] was quiet and stable.
Region 11346 [S17W02] was mostly quiet and stable. Flare: C2.6 at 01:33 UTC
Region 11347 [N09W09] decayed and was quiet.
Region 11350 [N26E31] was quiet and lost the mature penumbra on both polarities.
Region 11352 [S23E56] was mostly quiet and stable. Flare: C3.1 at 14:00 UTC
New region 11353 [N08E76] rotated into view at the northeast limb on Nov.16 and was numbered the next day by SWPC.
New region 11354 [S15E73] rotated partly into view at the southeast limb on Nov.16 and got an SWPC the following day.

Spotted regions not reported by NOAA/SWPC:
[S1327] emerged in the southeast quadrant on November 16. Location at midnight: S17E26
[S1330] rotated partly into view at the northeast limb on November 17. Location at midnight: N15E86
[S1331] emerged in the northeast quadrant on November 17. Location at midnight: N20E32

Several of the flares recorded during the day had an origin at or just behind the northeast limb. For instance the C6.0 flare at 07:27 UTC was produced by this very active region (and not by 11346 which was the source according to SWPC). This region obviously has M class flare potential.

A filament eruption was observed in the southwestern quadrant starting at 15:35 UTC in AIA 193 images. The associated CME does not appear to have any Earth directed component. A large eruption behind the northeast limb late in the day was the source of a CME observed late on Nov.17 and early on Nov.18.

Coronal mass ejections (CMEs)

November 15-17: 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

No obvious coronal holes are near Earth facing positions.

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 poor to fair. Propagation on long distance northeast-southwest paths is poor to fair.

Forecast

The geomagnetic field is expected to be quiet on November 17-19.

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
11341 2011.11.05 3 5 N09W76 0080 DSO CRO

location: N10W80

area: 0020

11342 2011.11.05 1 1 N16W87 0110 HSX HSX

area: 0200

11343 2011.11.05
2011.11.06
1 2 N27W64 0050 HSX HSX location: N29W65
S1318 2011.11.10     N15W54           plage
11346 2011.11.11
2011.11.12
3 14 S18W03 0060 CSO CSO  
11347 2011.11.12
2011.11.13
1 3 N08W10 0020 HSX CRO  
S1321 2011.11.12     N12W35         plage
S1322 2011.11.13     N10E06         plage
S1323 2011.11.13     N20W12         plage
11349 2011.11.14     N17W43         plage
11350 2011.11.14 2 14 N26E29 0080 DSO DRO location: N26E31
11351 2011.11.14     S24E09           region should be deleted, was trailing spots of region 11346
11352 2011.11.15
2011.11.16
3 11 S24E53 0140 ESO ESI location: S23E56
S1326 2011.11.15     S33W25           plage
S1327 2011.11.16   2 S17E26 0000   BXO  
11354 2011.11.16
2011.11.17
6 12 S15E73 0130 DAO DSI  
11353 2011.11.16
2011.11.17
1 1 N08E76 0030 HSX HSX  
S1330 2011.11.17   2 N15E86 0010   AXX    
S1331 2011.11.17   1 N20E32 0000   AXX    
Total spot count: 21 68  
Sunspot number: 111 188  (total spot count + 10 * number of spotted regions)
Classification adjusted SN: 66 107  (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): 67 85  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  164.4 (1) 79.3 (2A) / 139.9 (2B) (74.9 predicted, +4.4) (4.46)

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.