Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 1, 2013 at 04:55 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 June 30, 2013]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was quiet to unsettled on June 30. Solar wind speed at SOHO ranged between 456 and 592 km/s under the influence of a high speed stream from CH574.

Solar flux measured at 20h UTC on 2.8 GHz was 102.8 (decreasing 9.0 over the last solar rotation). The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.0). Three hour interval K indices: 32123223 (planetary), 33222323 (Boulder).

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

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

Region 11777 [S17W63] was quiet and stable.
Region 11778 [S16W32] decayed retaining only a few penumbra spots.
Region 11780 [S11W46] developed slowly and was mostly quiet.
Region 11781 [N22W32] developed slowly and has minor polarity intermixing. C class flaring is possible.
Region 11782 [S15E19] decayed slowly and could soon become spotless.
New region 11783 [N07E61] rotated into view on June 29 and was numbered the next day by SWPC.

Spotted regions not numbered by SWPC:
S2502 [S07W30] reemerged with penumbra spots.
New region S2516 [S15E48] emerged with penumbra spots.
New region S2517 [N12W03] emerged with a penumbra spot.

Coronal mass ejections (CMEs)

June 29-30: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
June 28: A partial halo CME was observed early in the day after and was associated with a long duration C4 event in AR 11777.

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

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.

Forecast

The geomagnetic field is expected to be quiet to unsettled on July 1 due to weakening effects from CH574 and a possible glancing CME impact from the CME observed on June 28. Quiet to unsettled is likely on July 2 becoming quiet on July 3-4.

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
11777 2013.06.19
2013.06.20
1 1 1 S18W63 0130 HSX HSX  
11778 2013.06.22 6 3 1 S18W28 0020 CRO AXX location: S16W32

area: 0007

S2498 2013.06.22       N15W18           plage
S2502 2013.06.24   4 2 S07W30 0012   BXO    
11779 2013.06.24
2013.06.25
      N17W14         plage
S2504 2013.06.24       N17W44           plage
11780 2013.06.25
2013.06.26
3 10 5 S13W45 0020 DRI DAO location: S11W46
S2508 2013.06.26       N03W18           plage
11782 2013.06.27
2013.06.28
1 2   S15E18 0010 AXX AXX area: 0002
S2510 2013.06.27       S11E04           plage
11781 2013.06.27
2013.06.28
12 28 12 N19W31 0090 DAI DAI area: 0150

location: N22W32

S2512 2013.06.27       S39W45           plage
S2514 2013.06.28       S36W19         plage
11783 2013.06.29
2013.06.30
2 2 2 N04E58 0010 BXO CRO area: 0020
S2516 2013.06.30   2   S15E48 0006   BXO    
S2517 2013.06.30   1 1 N12W03 0004   AXX    
Total spot count: 25 53 24  
Sunspot number: 85 143 94  (total spot count + 10 * number of spotted regions)
Weighted SN: 41 71 42  (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): 51 50 52 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
2013.06 110.1 (1) 79.8 (2A/2B) / 50.3 (2C) (59.0 projected, +0.3) (12.06)

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.