Solar Terrestrial Activity Report

Last major update issued on November 13, 2011 at 05:45 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 11, 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 12. Solar wind speed ranged between 346 and 461 km/s. A weak solar wind shock was observed at 05:09 UTC at SOHO, the arrival of the CME observed on November 9.

Solar flux measured at 20h UTC on 2.8 GHz was 168.8 (increasing 17.8 over the last solar rotation). The planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 2.3). Three hour interval K indices: 00111200 (planetary), 00112210 (Boulder).

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

At midnight UTC the visible solar disk had 11 spotted regions (in 2K resolution SDO images).

Region 11338 [S13W80] decayed slowly and quietly.
Region 11339 [N19W63] decayed slowly and was mostly quiet. Flare: C2.5 at 07:50 UTC.
Region 11340 [S08W29] was quiet and stable.
Region 11341 [N10W11] gained a few spots and was quiet.
Region 11342 [N16W21] decayed slowly and quietly.
Region 11343 [N28E01] was quiet and stable.
Region 11345 [S25W42] decayed slowly and quietly.
New region 11346 [S20E70] rotated partly into view on November 11 and was numbered the next day by SWPC.

Spotted regions not reported by NOAA/SWPC:
[S1317] emerged in the southern hemisphere near the central meridian on November 8 and developed slowly on Nov.9-11. (SWPC has this as region 11344, a separate region further south and which is now spotless). Location at midnight: S18W61. Flares: C1.8 at 16:43, C2.4 at 21:26 UTC.
[S1320] emerged in the northeast quadrant on November 12. Location at midnight: N09E56
[S1321] emerged in the northeast quadrant on November 12. Location at midnight: N12E32

Coronal mass ejections (CMEs)

November 11: A small partial halo CME was observed following a long duration event in region S1317 early in the day.
November 10, 12: 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 good. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet on November 13-16.

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
11338 2011.10.31
2011.11.01
6 4 S14W79 0120 DAO HSX

 

11339 2011.11.01 26 32 N18W62 0650 DAC CHO  
11344 2011.11.03
2011.11.07
22   S19W59 0200 DAI     spotless

SWPC is reusing 11344 instead of assigning a new number to to S1317

11340 2011.11.04
2011.11.05
1 2 S09W31 0080 HSX HSX area: 0120
11341 2011.11.05 4 15 N11W14 0080 CSO CSO

location: N10W11

area: 0140

11342 2011.11.05 2 7 N15W22 0140 HSX CSO

area: 0230

11343 2011.11.05
2011.11.06
1 4 N27W01 0140 HSX CSO location: N28E01

area: 0180

S1315 2011.11.08     S20W11           plage
S1316 2011.11.08     N03W44           plage
S1317 2011.11.08   24 S18W61 0220   DSI  
11345 2011.11.09 2 8 S26W41 0070 DSO CRO

area: 0030

S1318 2011.11.10     N15E11           plage
11346 2011.11.11
2011.11.12
1 6 S17E64 0080 HSX DSO location: S20E70

area: 0160

S1320 2011.11.12   5 N09E56 0010   BXO    
S1321 2011.11.12   3 N12E32 0000   BXO    
Total spot count: 65 110  
Sunspot number: 155 220  (total spot count + 10 * number of spotted regions)
Classification adjusted SN: 110 158  (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): 93 99  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  170.0 (1) 56.6 (2A) / 141.6 (2B) (74.9 predicted, +4.4) (5.43)

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.