Solar Terrestrial Activity Report

Last major update issued on January 14, 2012 at 06:00 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 14, 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 to unsettled on January 13. Solar wind speed ranged between 445 and 583 km/s under the influence of a high speed stream from CH492.

Solar flux measured at 20h UTC on 2.8 GHz was 124.1 (increasing 4.5 over the last solar rotation). The planetary A index was 7 (STAR Ap - based on the mean of three hour interval ap indices: 6.9). Three hour interval K indices: 23310111 (planetary), 13322221 (Boulder).

The background x-ray flux is at the class B6 level.

At midnight UTC the visible solar disk had 7 spotted regions (in 2K resolution SDO images).

Region 11391 [N12W67] decayed slowly and was mostly quiet. Flare: C2.2 at 06:05 UTC
Region 11395 [N22W04] decayed slowly and quietly.
Region 11396 [N26E19] developed quickly and has a weak magnetic delta structure in the southeastern part of the leading penumbra. C flares are likely.
New region 11397 [S19E29] emerged in the southeast quadrant on January 12 and got an SWPC number the next day.
New region 11398 [N13W08] emerged in the northeast quadrant on January 11 and was numbered by SWPC two days later. The region has polarity intermixing. C flares are possible.

Spotted regions not reported (or interpreted differently) by NOAA/SWPC:
[S1428] rotated into view at the southeast limb on January 13. Location at midnight: S23E84
[S1429] emerged in the southeast quadrant on January 13. Location at midnight: S13E11

Two interesting regions behind the northeast limb culd rotate into view today and tomorrow.

Coronal mass ejections (CMEs)

January 11-13: 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 recurrent trans equatorial coronal hole (CH493) was in an Earth facing position on January 12-13.

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

Forecast

The geomagnetic field is expected to be quiet on January 14 becoming quiet to unsettled on January 15-16 with a chance of active intervals due to effects from CH493.

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
11391 2012.01.02 11 7 N12W67 0120 DAO DAO  
11394 2012.01.05
2012.01.06
    N18W56           plage
S1411 2012.01.06     S20W31           plage
11395 2012.01.07
2012.01.08
2 8 N21W06 0040 HSX HSX

location: N22W04

S1415 2012.01.07     N12W38           plage
S1419 2012.01.08     S22W42           plage
S1420 2012.01.09     N30W54           plage
11396 2012.01.09
2012.01.12
10 22 N26E18 0070 DAI DAI beta-gamma-delta

area: 0180

S1422 2012.01.10     S16W17           plage
S1423 2012.01.10     S26W08           plage
S1424 2012.01.11     S16E47         plage
11398 2012.01.11
2012.01.13
4 14 N13W08 0015 DAO DAI area: 0070
11397 2012.01.12
2012.01.13
4 5 S20E48 0040 DAO DSO  
S1427 2012.01.12     S24E21         plage
S1428 2012.01.13   1 S23E84 0040   HSX    
S1429 2012.01.13   4 S13E11 0010   BXO    
Total spot count: 31 61  
Sunspot number: 81 131  (total spot count + 10 * number of spotted regions)
Weighted penumbral SN: 56 91  (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): 49 59  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
2012.01 132.4 (1) 34.5 (2A) / 82.4 (2B) (84.4 projected, +5.8) (4.65)

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.