Solar Terrestrial Activity Report

Last major update issued on January 19, 2012 at 05:55 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-24 (last update January 2, 2012)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update Jauary 2, 2012)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update January 2, 2012)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update January 5, 2012)]

[POES auroral activity level since October 2009 - updated January 17, 2012]
Annotated geomagnetic activity charts - Carrington rotation 2117 [November-December 2011] - 2118 [December 2011 - January 2012] NEW
[Solar polar fields vs solar cycles - updated June 27, 2011]

Recent activity

The geomagnetic field was quiet on January 18. Solar wind speed ranged between 353 and 431 km/s.

Solar flux measured at 22h UTC on 2.8 GHz was 148.1. The planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.1). Three hour interval K indices: 20011111 (planetary), 10012221 (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 11396 [N25W44] was mostly quiet and stable. Flare: C5.1 at 23:20 UTC
Region 11399 [S23E17] was mostly quiet and stable.
Region 11401 [N17E27] developed slowly and could produce further M class flares. Flares: C1.0 at 09:54, C2.4 at 10:30, M1.7/1N at 19:12 UTC.
Region 11402 [N29E28] has a large asymmetrical penumbra and could produce M class flares.
Region 11403 [S18W12] decayed slowly and quietly.
Region 11405 [N12E41] was quiet and stable.
Region 11406 [S22W71] decayed slowly and quietly.
New region 11407 [N18E15] emerged in the northeast quadrant.

Spotted regions not reported (or interpreted differently) by NOAA/SWPC:
[S1431] decayed slowly and quietly. Location at midnight: N10W22
[S1436] decayed slowly and quietly. Location at midnight: N16E38

Coronal mass ejections (CMEs)

January 18: A partial halo CME was observed after a filament eruption in the southern hemisphere near the central meridian. Activity increased in the filament after 08:50 UTC until eruption several hours later.
January 17
: 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

A poorly defined trans equatorial coronal hole (CH494) was in an Earth facing position on January 16-17. CH494 closed on January 17-18. A small coronal hole (CH495) in the southern hemisphere will be in an Earth facing position on January 20.

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 to unsettled on January 19-20 due to weak effects from CH494.

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
11395 2012.01.07
2012.01.08
    N20W72           plage
11396 2012.01.09
2012.01.12
4 5 N25W44 0010 BXO BXO plage
S1424 2012.01.11     S16W18           plage
11397 2012.01.12
2012.01.13
    S20W40           plage
S1427 2012.01.12     S24W44           plage
11399 2012.01.13
2012.01.14
1 6 S23E03 0020 HSX CRO  
11401 2012.01.14 18 38 N16E27 0450 EKC EHC beta-gamma
11402 2012.01.14 8 15 N28E27 0550 DKO CKO

 

11403 2012.01.14
2012.01.15
5 6 S19W11 0020 CRO BXO  
S1431 2012.01.14   1 N10W22 0000   AXX    
S1432 2012.01.14     N13W43           plage
11405 2012.01.15
2012.01.16
2 3 N11E39 0040 HSX CSO

location: N12E41

11404 2012.01.15
2012.01.16
    N11W56           plage
S1436 2012.01.16   1 N16E38 0000   AXX  
S1437 2012.01.16     N17W20           plage
11406 2012.01.16
2012.01.17
2 1 S24W68 0030 CSO HRX  
11407 2012.01.18 2 8 N17E13 0010 BXO DRO   location: N18E15
Total spot count: 42 84  
Sunspot number: 122 184  (total spot count + 10 * number of spotted regions)
Weighted penumbral SN: 80 118  (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): 73 83  k * (sunspot number). k = 0.6 for SWPC. k = 0.45 (changed from 0.33 on Nov.1, 2011) 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
2010.10 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 47.6 (+5.8) 9.18 / 8.94
2011.06 95.8 37.0 53.2 (+5.6) 8.96 / 8.06
2011.07 94.2 43.9 (57.8 projected, +4.6) 9.14 / 8.16
2011.08 101.7 50.6 (62.0 projected, +4.2) 8.16 / 7.26
2011.09 133.8 78.0 (65.3 projected, +3.3) 12.80 / 12.27
2011.10 137.3 88.0 (68.8 projected, +3.5) 7.52
2011.11 153.5 96.7 (73.2 projected, +4.3) 4.58
2011.12 141.3 73.0 (78.6 projected, +5.5) 3.32
2012.01 135.0 (1) 60.3 (2A) / 98.4 (2B) (84.4 projected, +5.8) (4.43)

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.