Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 11, 2013 at 05:00 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update January 1, 2013)] [Cycle 24 progress (last update January 1, 2013) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update January 1, 2013)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update January 1, 2013)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update January 2, 2013)]

[POES auroral activity level since October 2009 - updated October 7, 2012]
[Solar polar fields vs solar cycles - updated January 8, 2013]

Recent activity

The geomagnetic field was very quiet on January 10. Solar wind speed at SOHO ranged between 290 and 341 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 173.9 (increasing 54.7 over the last solar rotation). The Potsdam WDC planetary A index was 1 (STAR Ap - based on the mean of three hour interval ap indices: 1.4). Three hour interval K indices: 00000010 (planetary), 11121211 (Boulder).

The background x-ray flux was at the class C1 level.

At midnight UTC the visible solar disk had 14 spotted active regions (in 2K resolution SDO images).

Region 11642 [S24W54] was quiet and stable.
Region 11644 [N15W43] was quiet and stable.
Region 11648 [N07W30] decayed slowly and quietly.
Region 11649 [S15W06] was quiet and stable.
Region 11650 [S29W01] decayed and lost all trailing umbrae.
Region 11652 [N20E12] lost penumbral area. Many tiny spots are visible in the trailing polarity field.
Region 11653 [N09E07] was quiet and stable.
Region 11654 [N08E47] extended and has polarity intermixing, particularly in the leading spot section. Major M and X class flares are possible. The region produced the only C5+ flare of the day, a C8.0 event at 17:46 UTC.
Region 11655 [S20W10] was quiet and stable.

Spotted regions not numbered by SWPC:
S2163 [S19W33] reemerged with a tiny spot.
S2164 [S16E37] reemerged with tiny spots.
S2167 [S31E28] gained a tiny spot.
S2169 [N22E66] developed slowly and quietly.
S2170 [S13W13] decayed slowly and quietly.

Coronal mass ejections (CMEs)

January 8-10: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.

Coronal holes

Coronal hole history (since 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 currently in or near Earth facing positions.

Coronal hole map

The above coronal hole map is based on a method where coronal holes are detected automatically. While the method may need some fine tuning, 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 this method, the extent and intensity of both CHs 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 very good. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet on January 11-13.

Coronal holes (1) Coronal mass ejection (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 2K resolution) Compare to the previous day's image. 0.5k 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
2K 1K
11641 2012.12.29
2012.12.31
      N02W89           plage
11642 2012.12.30
2012.12.31
1 1 1 S24W56 0060 HSX HSX

area: 0130

location: S24W54

11643 2012.12.31
2013.01.02
      S14W67           plage
11644 2013.01.01
2013.01.02
1 3 1 N15W44 0020 HSX HRX  
11648 2013.01.02
2013.01.04
  1   N05W27 0000   AXX location: N07W30
11646 2013.01.02
2013.01.03
      N13W37         plage
11651 2013.01.02
2013.01.04
      N20W33         plage
11649 2013.01.03
2013.01.04
1 3 2 S15W07 0060 HSX HSX area: 0140
S2156 2013.01.03       N17W33           plage
11650 2013.01.04 8 16 11 S29E01 0120 EAO CAO

area: 0150

11652 2013.01.05 29 62 26 N20E11 0230 EAC EAI

beta-gamma

area: 0260

11653 2013.01.05 1 3 1 N11E06 0010 HSX CRO location: N09E07
S2157 2013.01.05       S02W36           plage
S2159 2013.01.05       N25W59           plage
S2160 2013.01.06       S18W42           plage
11654 2013.01.07 21 47 27 N08E47 0770 FKI FKC

area: 1150

S2162 2013.01.07       N20W14           plage
S2163 2013.01.07   1   S19W33 0000   AXX    
S2164 2013.01.08   3   S16E37 0000   BXO    
11655 2013.01.08
2013.01.09
3 8 4 S20W10 0030 CSO CRO  
S2166 2013.01.08       N27W48           plage
S2167 2013.01.09   2   S31E28 0000   AXX  
S2168 2013.01.09       N11E26         plage
S2169 2013.01.09   3 1 N22E66 0010   CRO  
S2170 2013.01.09   3 2 S13W13 0000   BXO  
Total spot count: 65 156 76  
Sunspot number: 145 296 176  (total spot count + 10 * number of spotted regions)
Weighted SN: 110 198 118  (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): 87 104 97 k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for STAR SDO 2K, k = 0.55 for STAR SDO 1K

Monthly solar cycle data

Month Average measured solar flux International sunspot number (SIDC) Smoothed sunspot number Average ap
(3)
2011.10 137.3 88.0 59.9 (+0.4) 8.28
2011.11 153.5 (cycle max) 96.7 (cycle max) 61.1 (+1.2) 5.55
2011.12 141.3 73.0 63.4 (+2.3) 3.78
2012.01 132.5 58.3 65.5 (+2.1) 7.15
2012.02 106.5 32.9 66.9 (+1.4)
possible cycle 24 max
8.81
2012.03 114.7 64.3 66.8 (-0.1) 16.08
2012.04 113.0 55.2 64.6 (-2.2) 10.10
2012.05 121.5 69.0 61.7 (-2.9) 7.06
2012.06 119.6 64.5 58.9 (-2.8) 10.08
2012.07 133.9 66.5 (57.4 projected, -1.5) 13.90
2012.08 115.4 63.1 (58.3 projected, +0.9) 7.96
2012.09 122.9 61.5 (58.9 projected, +0.6) 8.07
2012.10 123.3 53.3 (58.3 projected, -0.6) 9.97
2012.11 121.3 61.4 (57.6 projected, -0.7) 7.08
2012.12 108.6 40.8 (56.9 projected, -0.7) 3.44
2013.01 144.5 (1) 47.6 (2A) / 147.7 (2B) / 62.5 (2C) (56.2 projected, -0.7) (2.06)

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) Boulder SN current month average to date. 2C) STAR SDO 1K Wolf number 30 day average.
3) Running average based on the quicklook and definitive Potsdam WDC ap indices. Values in red are based on the definitive international Potsdam WDC 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.