Solar Terrestrial Activity Report

Last major update issued on November 7, 2011 at 05:20 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 4, 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 6. Solar wind speed ranged between 271 and 369 km/s. A weak disturbance was in progress during the latter half of the day.

Solar flux measured at 20h UTC on 2.8 GHz was 176.7 (increasing 50.3 over the last solar rotation, and the highest (not enhanced by flares) measured solar flux of cycle 24). 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: 10001212 (planetary), 00012312 (Boulder).

The background x-ray flux is at the class B7 level.

At midnight UTC the visible solar disk had 10 spotted regions (in 2K resolution SDO images).

Region 11334 [N12W75] was quiet and stable
Region 11336 [N17W23] reemerged with several tiny spots.
Region 11337 [N25W10] decayed slowly and quietly.
Region 11338 [S13E03] developed slowly. Opposite polarity spots with rudimentary penumbra could be forming a magnetic delta structure in the central southern part. Flares: C2.3 at 08:16, C2.0 at 17:36, C1.2 at 19:58, C1.7 at 21:53 UTC.
Region 11339 [N19E18] didn't change significantly and still has the potential to produce a major flare. Flares: M1.2 at 01:03, M1.4 at 06:14, C8.8 at 09:56, C5.3 at 14:47 UTC.
Region 11340 [S08E51] added a trailing spot and was quiet.
Region 11341 [N10E70] was quiet and stable.
Region 11342 [N18E65] was quiet and stable.
New region 11343 [N27E77] rotated partly into view late on November 5 and was numbered by SWPC the next day.

Spotted regions not reported by NOAA/SWPC:
[S1308] reemerged with several spots on November 6. Location at midnight: S22E19

Coronal mass ejections (CMEs)

November 4-6: 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 small coronal hole (CH484) in the northern hemisphere was in an Earth facing position on November 3.

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

Forecast

The geomagnetic field is expected to be quiet to unsettled on November 7 due to weak effects from CH484 and quiet on November 8-9.

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 polarity overlay
Comment
SWPC STAR SDO SWPC STAR Current Previous
11336 2011.10.29
2011.10.31
  5 N11W30 0000   BXO   location: N17W23
11334 2011.10.29
2011.10.30
2 2 N12W73 0040 HAX HAX  
11337 2011.10.30
2011.10.31
  3 N18W14 0000   AXX location: N25W10
11338 2011.10.31
2011.11.01
9 25 S14E02 0240 DSO DSI beta-gamma

area: 0400

11339 2011.11.01 42 72 N19E31 1250 EKC FKC beta-gamma-delta

location: N19E18

S1308 2011.11.03   4 S22E19 0010   BXO    
S1309 2011.11.03     S22W27           plage
11340 2011.11.04
2011.11.05
1 2 S09E49 0080 CAO CSO location: S08E51
S1311 2011.11.04     N16W01           plage
11341 2011.11.05 1 7 N08E66 0120 HSX CAO location: N10E70
11342 2011.11.05 6 10 N18E62 0110 DAO DAO location: N18E65
11343 2011.11.05
2011.11.06
1 1 N29E76 0060 HSX HSX location: N27E77

area: 0130

S1313 2011.11.05     N25W41        

plage

Total spot count: 62 131  
Sunspot number: 132 231  (total spot count + 10 * number of spotted regions)
Classification adjusted SN: 102 171  (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): 79 104  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  162.5 (1) 24.8 (2A) / 124.2 (2B) (74.9 predicted, +4.4) (7.71)

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.