Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 8, 2013 at 06:30 UTC. Irregular updates are likely until July 12.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update July 1, 2013)] [Cycle 24 progress (last update July 1, 2013) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update July 1, 2013)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update July 1, 2013)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update July 1, 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 active on July 7. Solar wind speed at SOHO ranged between 289 and 323 km/s. The disturbance that began on July 4 ended early on July 7.

Solar flux measured at 20h UTC on 2.8 GHz was 125.6 (increasing 32.3 over the last solar rotation). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 5.8). Three hour interval K indices: 41101110 (planetary), 41112221 (Boulder).

The background x-ray flux was at the class B4 level.

At 15h UTC the visible solar disk had 10 spotted active regions (in 2K resolution SDO images).

Region 11784 [S15W50] decayed slowly and quietly.
Region 11785 [S10W03] lost some penumbral area while there was little change in the number of spots. The region has a weak magnetic delta structure. An M class event is still possible. C5+ event: C6.1 impulsive flare at 00:58 UTC.
Region 11787 [S16E19] gained a few spots and developed a magnetic delta structure. An M class flare is possible.
New region 11789 [S26E21] emerged on July 6 and was numbered the next day by SWPC.
New region 11790 [S16E46] emerged on July 6, developed slowly early in the day, then began to decay.

Spotted regions not numbered by SWPC:
S2523 [S25W03] was quiet and stable.
S2525 [N05W13] decayed slowly and quietly.
S2534 [N17E42] lost one spot while another penumbra spot emerged.
New region S2536 [S28E31] emerged with penumbra spots.
New region S2537 [N22E48] emerged with a penumbra spot.

Coronal mass ejections (CMEs)

July 5-7: 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

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 mostly quiet on July 8-10.

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
11782 2013.06.27
2013.06.28
      S15W79           plage
11783 2013.06.29
2013.06.30
      N07W42          

plage

11784 2013.06.30
2013.07.01
10 22 9 S15W49 0080 DAO CRI

area: 0050

11785 2013.07.01 29 105 45 S10W02 0610 EKC FKC beta-gamma-delta

area: 0900

11786 2013.07.01
2013.07.02
      S31W53           plage
S2519 2013.07.01       S17W34           plage
11788 2013.07.01
2013.07.05
      S15W10           merged with AR 11787
S2521 2013.07.01       N12W44           plage
S2522 2013.07.01       S21W57           plage
S2523 2013.07.02   1   S25W03 0001   AXX  
11787 2013.07.02
2013.07.03
19 52 28 S14E17 0140 EAI EAC beta-gamma-delta

area: 0370

location: S16E19

S2525 2013.07.02   2 1 N05W13 0006   BXO  
S2526 2013.07.02       N05W04           plage
S2531 2013.07.03       S16W57           plage
11789 2013.07.06
2013.07.07
2 5 3 S24E22 0013 BXO CRO area: 0020
11790 2013.07.06
2013.07.07
2 3 1 S15E45 0010   AXX  
S2534 2013.07.06   1   N17E42 0002   AXX  
S2535 2013.07.06       N00W58         plage
S2536 2013.07.07   2 1 S28E31 0006   BXO    
S2537 2013.07.07   1   N22E48 0001   AXX    
Total spot count: 62 194 88  
Sunspot number: 112 294 158  (total spot count + 10 * number of spotted regions)
Weighted SN: 82 215 109  (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): 67 103 87 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
2012.04 113.0 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 59.6 (-0.1) 3.44
2013.01 127.1 62.9 (58.7 projected, -0.9) 4.69
2013.02 104.3 38.0 (58.3 projected, -0.4) 6.11
2013.03 111.3 57.9 (57.9 projected, -0.4) 10.56
2013.04 124.8 72.4 (57.5 projected, -0.4) 5.40
2013.05 131.4 78.7 (57.6 projected, +0.1) 9.73
2013.06 110.1 52.5 (57.9 projected, +0.3) 12.06
2013.07 126.4 (1) 24.1 (2A) / 106.6 (2B) / 58.8 (2C) (58.0 projected, +0.1) (7.36)

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 the 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.