Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 5, 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 on July 4. Solar wind speed at SOHO ranged between 322 and 391 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 137.7 (increasing 27.9 over the last solar rotation). The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.3). Three hour interval K indices: 10000112 (planetary), 10112222 (Boulder).

The background x-ray flux was at the class B8 level.

At midnight UTC the visible solar disk had 8 spotted active regions (in 2K resolution SDO images).

Region 11779 [N16W65] reemerged with a penumbra spot.
Region 11783 [N06E08] reemerged with a penumbra spot.
Region 11784 [S15W08] developed slowly and was mostly quiet. The region has minor polarity intermixing. C flares are possible.
Region 11785 [S09E38] developed adding many spots. There's lots of polarity intermixing. A major flare is possible. C5+ flare: C8.9 at 00:04 UTC.
Region 11787 [S15E57] lost the magnetic delta structure while adding several small spots. An M class flare is possible. C5+ events: C5.9/1N at 18:54, C6.8/1F at 19:44 UTC.

Spotted regions not numbered by SWPC:
S2520 [S15E32] decayed slowly and quietly.
S2521 [N10W06] reemerged with a penumbra spot.
S2529 [N21W30] was quiet and stable.

Coronal mass ejections (CMEs)

July 2-4: 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 to fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be mostly quiet on July 5-7.

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
11778 2013.06.22       S18W84           plage
S2502 2013.06.24       S08W85         plage
11779 2013.06.24
2013.06.25
  1 1 N17W70 0005   AXX   location: N16W65
11782 2013.06.27
2013.06.28
      S15W37         plage
S2510 2013.06.27       S11W48           plage
11781 2013.06.27
2013.06.28
1     N22W81 0010 AXX      
11783 2013.06.29
2013.06.30
  1 1 N07E03 0003   AXX  

location: N06E08

11784 2013.06.30
2013.07.01
13 26 19 S15W09 0070 DSI DAI beta-gamma

area: 0120

S2517 2013.06.30       N12W55           plage
11785 2013.07.01 43 102 44 S12E36 0630 FKC EKC beta-gamma

area: 1150

location: S09E38

11786 2013.07.01
2013.07.02
      S31W11         plage
S2519 2013.07.01       S17E05           plage
S2520 2013.07.01   10 6 S15E32 0040   DRO  
S2521 2013.07.01   1   N10W06 0003   AXX    
S2522 2013.07.01       S21W18           plage
S2523 2013.07.02       S23E37         plage
11787 2013.07.02
2013.07.03
12 43 16 S14E56 0160 DAO DAC beta-gamma

area: 0240

S2525 2013.07.02       N10E21           plage
S2526 2013.07.02       N09E42           plage
S2529 2013.07.02   1 1 N21W30 0004   AXX  
S2530 2013.07.03       N00W49         plage
S2531 2013.07.03       S16W18         plage
Total spot count: 69 185 88  
Sunspot number: 109 265 158  (total spot count + 10 * number of spotted regions)
Weighted SN: 89 208 111  (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): 65 93 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
2013.07 121.1 (1) 13.1 (2A) / 101.5 (2B) / 53.9 (2C) (58.0 projected, +0.1) (3.97)

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.