Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 25, 2013 at 04:35 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update June 1, 2013)] [Cycle 24 progress (last update June 1, 2013) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update June 1, 2013)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update June 1, 2013)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update June 6, 2013)]

[POES auroral activity level since October 2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated May 12, 2013]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was quiet to active on June 24. Solar wind speed at SOHO ranged between 472 and 570 km/s under the inlfuence of a high speed stream from CH573.

Solar flux measured at 20h UTC on 2.8 GHz was 120.6 (increasing 15.8 over the last solar rotation). The Potsdam WDC planetary A index was 13 (STAR Ap - based on the mean of three hour interval ap indices: 13.4). Three hour interval K indices: 33223343 (planetary), 23233333 (Boulder).

The background x-ray flux was at the class B3 level.

At midnight UTC the visible solar disk had 15 spotted active regions (in 2K resolution SDO images).

Region 11770 [S14W76] decayed slowly and quietly.
Region 11772 [S22W74] decayed further and was quiet.
Region 11773 [N04W56] was quiet and stable.
Region 11774 [S16W64] decayed slowly and quietly.
Region 11775 [S26W43] decayed slowly and was mostly quiet.
Region 11776 [N10W75] decayed slowly and quietly.
Region 11777 [S17E17] decayed slowly and quietly.
Region 11778 [S18E50] decayed slowly and has polarity intermixing. C5+ flare: impulsive C9.9/1N at 11:32 UTC.

Spotted regions not numbered by SWPC:
S2492 [N10W30] decayed slowly and quietly.
S2498 [N15E47] decayed slowly and quietly.
S2500 [N14W05] was quiet and stable.
S2501 [S22W26] decayed slowly and quietly.
New region S2502 [S06E52] emerged with a penumbra spot.
New region S2503 [N16E68] emerged with penumbra spots.
New region S2504 [N17E34] emerged with a penumbra spot.

Coronal mass ejections (CMEs)

June 22-24: 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 large northern hemisphere coronal hole (CH573) was in a geoeffective position on June 17-22. A recurrent trans equatorial coronal hole (CH574] will rotate into an Earth facing position on June 25-26.

Coronal hole map

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 fair to good.

Forecast

The geomagnetic field is expected to be quiet to active on June 25 due to a high speed stream from CH573. Quiet to unsettled is likely on June 26-27 becoming quiet to minor storm on June 28-29 as a high speed stream from CH574 becomes the dominant solar wind source.

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 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
11770 2013.06.12
2013.06.13
  1   S15W77 0003   AXX  
11769 2013.06.12
2013.06.13
      S22W87           merged with AR 11772
11772 2013.06.13
2013.06.14
1 2 1 S22W78 0100 HAX HAX  
11771 2013.06.13
2013.06.14
      S15W70           plage
11773 2013.06.14
2013.06.15
  1   N04W62 0001   AXX location: N04W56
11774 2013.06.14
2013.06.15
4 5 1 S17W64 0040 CAO BXO area: 0015
11775 2013.06.14
2013.06.15
7 11 6 S26W45 0220 DSC DSO  
S2482 2013.06.15       S21W37         plage
11776 2013.06.18 4 8 4 N11W76 0130 DSO DAO  
S2490 2013.06.19       S16W01         plage
11777 2013.06.19
2013.06.20
2 6 2 S15E16 0170 HSX CSO area: 0230
S2492 2013.06.20   2   N10W30 0003   BXO images/AR_S2492_20130623_2345.jpg  
S2493 2013.06.20       N20W52          
S2496 2013.06.21       N02W35           plage
S2497 2013.06.21       N14W39         plage
11778 2013.06.22 4 21 6 S16E49 0080 CAO CAO beta-gamma
S2498 2013.06.22   1   N15E47 0002   AXX  
S2500 2013.06.23   3 1 N14W05 0010   AXX  
S2501 2013.06.23   2 1 S22W26 0009   BXO  
S2502 2013.06.24   1   S06E52 0002   AXX    
S2503 2013.06.24   2 2 N16E68 0016   BXO    
S2504 2013.06.24   1   N17E34 0001   AXX    
Total spot count: 22 67 25  
Sunspot number: 82 217 125  (total spot count + 10 * number of spotted regions)
Weighted SN: 52 92 49  (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 76 63 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)
2011.11 153.5 (cycle peak) 96.7 (cycle peak) 61.1 (+1.2) 5.55
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 57.7 (-1.2) 13.90
2012.08 115.4 63.0 58.1 (+0.4) 7.96
2012.09 122.9 61.4 58.1 (-0.0) 8.07
2012.10 123.3 53.3 58.6 (+0.5) 9.97
2012.11 121.3 61.8 59.7 (+1.1) 7.08
2012.12 108.6 40.8 (59.5 projected, -0.2) 3.44
2013.01 127.1 62.9 (59.1 projected, -0.4) 4.69
2013.02 104.3 38.0 (59.3 projected, +0.2) 6.11
2013.03 111.3 57.9 (58.9 projected, -0.4) 10.56
2013.04 124.8 72.4 (58.6 projected, -0.3) 5.40
2013.05 131.4 78.7 (58.7 projected, +0.1) 9.73
2013.06 110.7 (1) 57.4 (2A) / 78.3 (2B) / 51.0 (2C) (59.0 projected, +0.3) (10.98)

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.