Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 12, 2013 at 06:00 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 quiet on January 11. Solar wind speed at SOHO ranged between 273 and 347 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 172.3 (increasing 49.9 over the last solar rotation). The Potsdam WDC planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 2.1). Three hour interval K indices: 00011012 (planetary), 01011112 (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 [S25W68] was quiet and stable.
Region 11644 [N14W56] decayed slowly and quietly.
Region 11648 [N05W42] was quiet and stable.
Region 11649 [S15W20] was quiet and stable.
Region 11650 [S30W14] was quiet and stable.
Region 11652 [N19W02] decayed in the trailing spot section while penumbral area increased in the leading spot section. The region has polarity intermixing and could produce a minor M class flare.
Region 11653 [N08W07] was quiet and stable.
Region 11654 [N08E33] developed a weak magnetic delta structure in a small penumbra in the southwestern section. Further M class flaring is likely, a major flare is possible. C5+ Flares: C9.2 at 06:14, M1.2 at 09:11, M1.0/1F at 15:07 UTC.
Region 11655 [S21W25] decayed slowly and quietly.
New region 11656 [N22E55] rotated into view on January 9 and was numbered by SWPC 2 days later as it developed penumbra on both polarities.
New region 11657 [S17E24] emerged on January 8 and got its NOAA number 3 days later. The region developed early on January 11, then decayed.

Spotted regions not numbered by SWPC:
S2167 [S32E15] was quiet and stable.
S2170 [S14W27] decayed and could become spotless today.
New region S2171 [S04E02] emerged with tiny spots.

Coronal mass ejections (CMEs)

January 9-11: 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 good. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet on January 12-14.

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
11642 2012.12.30
2012.12.31
1 1 1 S25W70 0110 HSX HSX

 

11643 2012.12.31
2013.01.02
      S14W81           plage
11644 2013.01.01
2013.01.02
1 2 1 N15W58 0020 HSX HRX  
11648 2013.01.02
2013.01.04
  1 1 N05W42 0000   AXX  
11646 2013.01.02
2013.01.03
      N13W51           plage
11651 2013.01.02
2013.01.04
      N20W33         plage
11649 2013.01.03
2013.01.04
3 5 2 S16W21 0060 CAO CAO area: 0120
S2156 2013.01.03       N17W46           plage
11650 2013.01.04 2 12 5 S28W16 0110 CAO CSO

location: S30W14

11652 2013.01.05 16 43 25 N19W00 0210 EAI EAI

beta-gamma

11653 2013.01.05 2 3 1 N09W08 0010 CAO CRO  
S2157 2013.01.05       S02W49           plage
S2160 2013.01.06       S18W55           plage
11654 2013.01.07 36 56 29 N08E31 1100 FKI FKC

beta-gamma-delta

area: 1400

S2162 2013.01.07       N20W27           plage
S2163 2013.01.07       S19W46         plage
11657 2013.01.08
2013.01.11
2 1 1 S16E37 0010 CRO AXX  
11655 2013.01.08
2013.01.09
2 6 2 S21W24 0010 CRO CRO  
S2167 2013.01.09   2   S32E14 0000   AXX  
S2168 2013.01.09       N11E13           plage
11656 2013.01.09
2013.01.11
1 10 5 N22E52 0010 AXX DAO area: 0060

location: N22E55

S2170 2013.01.09   1   S14W27 0000   AXX  
S2171 2013.01.11   2 1 S04E02 0000   BXO    
Total spot count: 66 145 74  
Sunspot number: 166 285 194  (total spot count + 10 * number of spotted regions)
Weighted SN: 112 189 118  (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): 100 100 107 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
2013.01 147.0 (1) 53.0 (2A) / 149.4 (2B) / 64.0 (2C) (56.2 projected, -0.7) (2.07)

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.