Solar Terrestrial Activity Report

Last major update issued on November 30, 2011 at 05:35 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 28, 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 to unsettled on November 29. Solar wind speed ranged between 412 and 482 km/s under the influence of CME effects. The interplanetary magnetic field was mostly northwards making this a fairly weak disturbance.

Solar flux measured at 20h UTC on 2.8 GHz was 140.6 (decreasing 13.0 over the last solar rotation). The planetary A index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 8.6). Three hour interval K indices: 33221131 (planetary), 33322232 (Boulder).

The background x-ray flux is at the class B5 level.

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

Region 11355 [N15W74] was quiet and stable.
Region 11356 [N17W50] was mostly quiet and stable. Flare: C1.1 at 01:15 UTC
Region 11358 [N22W13] decayed further retaining only rudimentary penumbra on the trailing spots.
Region 11361 [N20E08] developed further and has minor polarity intermixing. Further C class flaring is likely. Flare: C2.1 at 03:32 UTC
Region 11362 [N08E52] developed slowly and has polarity intermixing. Further development near the northern edge of the leading penumbra could create a magnetic delta structure. Flare: C2.5 at 09:00 UTC
New region 11363 rotated into view at the southeast limb on November 28 and was numbered the next day by SWPC.
New region 11364 rotated fully into view at the northeast limb.

Spotted regions not reported by NOAA/SWPC:
[S1338] emerged in the northeast quadrant on November 26. Location at midnight: N17E17
[S1342] was split off from region 11363, the region is located to the southeast of 11363. Location at midnight: S23E74. Flare: C1.1 at 22:26 UTC
[S1343] emerged in the southeast quadrant on November 29. Location at midnight: S10E53

Coronal mass ejections (CMEs)

November 27: A filament eruption near the center of the visible disk was observed beginning at 11:12 UTC. A small and slow moving CME was observed beginning at 11:24 UTC in STEREO-A images, this CME preceeded a larger backsided CME.
November 28-29: 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 coronal hole (CH486) in the southern hemisphere was in an Earth facing position on November 26-27.

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

Forecast

The geomagnetic field is expected to be quiet to unsettled on Nov.30 and December 1 due to coronal hole effects and quiet on December 2.

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
11355 2011.11.17
2011.11.18
1 1 N14W73 0040 HSX HSX

 

11356 2011.11.19 4 10 N16W50 0080 ESO CSO

 

11358 2011.11.22 12 19 N20W12 0130 DSI DSO

location: N22W12

11361 2011.11.24
2011.11.25
9 20 N18E07 0080 DSO DAI beta-gamma
11360 2011.11.24
2011.11.25
    N17W45           plage
S1337 2011.11.25     S17E27           plage
S1338 2011.11.26   1 N17E17 0000   AXX  
11362 2011.11.27 8 12 N08E49 0110 DSO DAO beta-gamma

area: 0260

11363 2011.11.28
2011.11.29
1 1 S18E67 0040 HSX HSX area: 0090

location: S17E69

11364 2011.11.28
2011.11.29
1 2 N17E73 0030 HSX CSO area: 0100

location: N19E76

S1342 2011.11.29   6 S23E74 0120   DAO   split off from S1339
S1343 2011.11.29   1 S10E53 0000   AXX    
Total spot count: 36 73  
Sunspot number: 106 173  (total spot count + 10 * number of spotted regions)
Weighted penumbral SN: 71 113  (Sum of total spot count + classification weighting for each AR. Classification weighting: X=0, R=3, A/S=5, H/K=10)
Relative sunspot number (Wolf number): 64 78  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
2010.09 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  153.8 (1) 128.9 (2A) / 133.4 (2B) (74.9 predicted, +4.4) (4.38)

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.