Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 18, 2013 at 05:35 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 active on January 17. Solar wind speed at SOHO ranged between 338 and 434 km/s. A fairly weak CME influenced the field after noon causing unsettled to active conditions. The disturbance decreased in intensity towards the end of the day and conditions are again quiet early on Janaury 18.

Solar flux measured at 20h UTC on 2.8 GHz was 122.7 (increasing 8.1 over the last solar rotation). The Potsdam WDC planetary A index was 14 (STAR Ap - based on the mean of three hour interval ap indices: 14.4). Three hour interval K indices: 33223433 (planetary), 33213532 (Boulder).

The background x-ray flux was at the class B2 level.

At midnight UTC the visible solar disk had 9 spotted active regions (in 2K resolution SDO images).

Region 11652 [N19W85] decayed slowly and quietly.
Region 11654 [N07W47] decayed slowly and quietly.
Region 11656 [N23W22] was quiet and stable.
Region 11658 [S12E08] was quiet and stable.
New region 11659 [N04E54] rotated into view on January 16 and was numbered by SWPC the next day.

Spotted regions not numbered by SWPC:
S2175 [S18W08] added spots in the southern part of the extensive plage area.
New region S2181 [N15E45] emerged with tiny spots.
New region S2182 [N16E29] emerged with tiny spots.
New region S2183 [S42E03] emerged with a tiny spot.

Coronal mass ejections (CMEs)

January 15, 17: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
January 16: An eruption near old AR 11650 close to the southwest limb was recorded as a long duration C2.2 event peaking at 19:23 UTC. The event was associated with a minor increase in proton flux levels and a partial halo CME.

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

Forecast

The geomagnetic field is expected to be quiet to unsettled on January 18 and quiet on January 19. On January 20 there's a slight chance the CME observed on January 16 could arrive. If it does unsettled to active conditions are likely, otherwise expect quiet conditons.

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
11652 2013.01.05 2 1   N18W82 0030 HAX HRX

 

11654 2013.01.07 27 35 23 N07W47 0540 FKC FKI

beta-gamma

11657 2013.01.08
2013.01.11
      S17W61           plage
11656 2013.01.09
2013.01.11
  5   N21W28 0000   BXO

 

11658 2013.01.12
2013.01.13
2 6 4 S13E08 0070 HAX CSO  
S2173 2013.01.13       S22W01           plage
S2175 2013.01.14   9 1 S18W08 0010   BXO  
S2176 2013.01.15       N09W15           plage
S2177 2013.01.15       S12W44           plage
S2178 2013.01.15       S23W36           plage
11659 2013.01.16
2013.01.17
3 3 2 N04E53 0010 BXO AXX  
S2180 2013.01.16       S13W58         plage
S2181 2013.01.17   4 1 N15E45 0000   BXO    
S2182 2013.01.17   2 1 N16E29 0000   AXX    
S2183 2013.01.17   1   S42E03 0000   AXX    
Total spot count: 34 66 32  
Sunspot number: 74 156 92  (total spot count + 10 * number of spotted regions)
Weighted SN: 54 84 50  (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): 44 55 51 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
2013.01 146.8 (1) 74.5 (2A) / 135.8 (2B) / 69.9 (2C) (56.2 projected, -0.7) (3.94)

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.