Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 15, 2013 at 02:35 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 to unsettled on January 14. Solar wind speed at SOHO ranged between 465 and 557 km/s under the influence of a high speed coronal hole stream.

Solar flux measured at 20h UTC on 2.8 GHz was 154.1 (increasing 37.9 over the last solar rotation). The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.1). Three hour interval K indices: 33122121 (planetary), 32222321 (Boulder).

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

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

Region 11649 [S15W58] decayed slowly and quietly.
Region 11650 [S30W52] decayed slowly and quietly.
Region 11652 [N19W43] decayed slowly and became less active during the latter half of the day. C5+ flares: impulsive C6.5 at 01:22 UTC.
Region 11654 [N07W07] gained a few spots, however, the central penumbra is fragmenting and penumbral area decreased slightly. The region only produced 2 small C flares during the day.
Region 11656 [N22E16] decayed slowly and quietly.
Region 11658 [S12E49] was quiet and stable.

Spotted regions not numbered by SWPC:
S2170 [S13W65] decayed slowly and quietly.
S2173 [S22E38] was quiet and stable.
S2174 [N12W76] decayed slowly and quietly.
New region S2175 [S08E22] emerged with tiny spots.

Coronal mass ejections (CMEs)

January 12-14: 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 poor to fair. Propagation on long distance northeast-southwest paths is poor to fair.

Forecast

The geomagnetic field is expected to be quiet on January 15-17.

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
11648 2013.01.02
2013.01.04
      N05W85           plage
11651 2013.01.02
2013.01.04
      N20W88           plage
11649 2013.01.03
2013.01.04
2 1 1 S15W62 0030 HAX HRX  
11650 2013.01.04 1 7 3 S30W52 0050 HAX HRX

 

11652 2013.01.05 5 11 6 N18W44 0160 HAX CAO

beta-gamma

11653 2013.01.05       N09W49         plage
11654 2013.01.07 49 65 35 N08W05 0920 FKC FKC

beta-gamma-delta

area: 1300

location: N07W07

11657 2013.01.08
2013.01.11
      S17W19           plage
11655 2013.01.08
2013.01.09
      S21W65           plage
S2167 2013.01.09       S34W21         plage
S2168 2013.01.09       N11W26           plage
11656 2013.01.09
2013.01.11
4 4 2 N23E15 0010 BXO CRO

 

S2170 2013.01.09   1   S13W65 0000   AXX  
S2171 2013.01.11       S04W37           plage
11658 2013.01.12
2013.01.13
7 9 5 S11E51 0090 CSO CAO  
S2173 2013.01.13   3 2 S22E38 0010   BXO  
S2174 2013.01.13   2   N12W76 0000   AXX  
S2175 2013.01.14   2   S08E22 0000   AXX    
Total spot count: 68 105 54  
Sunspot number: 128 205 124  (total spot count + 10 * number of spotted regions)
Weighted SN: 98 134 83  (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): 77 72 68 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
2013.01 149.7 (1) 66.2 (2A) / 146.6 (2B) / 68.6 (2C) (56.2 projected, -0.7) (3.14)

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.