Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 27, 2013 at 04:25 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 very quiet on June 26. Solar wind speed at SOHO ranged between 392 and 472 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 106.5 (increasing 2.4 over the last solar rotation). The Potsdam WDC planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 2.3). Three hour interval K indices: 00000101 (planetary), 10011211 (Boulder).

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

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

Region 11775 [S25W69] decayed slowly and quietly.
Region 11777 [S17W10] was quiet and stable.
Region 11778 [S17E25] was mostly quiet and stable. The region has polarity intermixing and could produce C flares.
Region 11779 [N15E41] decayed slowly and quietly.
New region 11780 [S09E11] emerged quietly.

Spotted regions not numbered by SWPC:
S2482 [S22W58] reemerged with a penumbra spot.
S2500 [N16W30] reemerged with penumbra spots.
New region S2507 [N23W51] emerged with a penumbra spot.
New region S2508 [N03E34] emerged with a penumbra spot.

Coronal mass ejections (CMEs)

June 24-26: 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 (CH574] was in 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 poor.

Forecast

The geomagnetic field is expected to be quiet on June 27. Quiet to minor storm conditions are possible 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
11774 2013.06.14
2013.06.15
1     S16W90 0010 AXX       plage
11775 2013.06.14
2013.06.15
3 3 1 S25W70 0090 CSO HSX  
S2482 2013.06.15   1   S22W58 0002   AXX    
S2490 2013.06.19       S16W27           plage
11777 2013.06.19
2013.06.20
2 9 2 S14W11 0130 HSX CSO area: 0200
S2492 2013.06.20       N10W56           plage
11778 2013.06.22 5 29 15 S17E22 0080 CSO DAI  
S2498 2013.06.22       N15E21            
S2500 2013.06.23   3   N16W30 0007   AXX    
S2501 2013.06.23       S22W52            
S2502 2013.06.24       S06E26           plage
11779 2013.06.24
2013.06.25
3 4 1 N15E39 0010 BXO BXO  
S2504 2013.06.24       N17E08           plage
S2505 2013.06.25   2   N14W10 0004   AXX  
11780 2013.06.25
2013.06.26
1 4 1 S09E10 0000 BXO BXO area: 0008
S2507 2013.06.26   1   N23W51 0001   AXX    
S2508 2013.06.26   1   N03E34 0002   AXX    
Total spot count: 15 57 20  
Sunspot number: 75 157 70  (total spot count + 10 * number of spotted regions)
Weighted SN: 30 72 35  (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): 45 55 39 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
2013.06 111.6 (1) 69.6 (2A) / 80.3 (2B) / 50.4 (2C) (59.0 projected, +0.3) (10.73)

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.