Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 11, 2013 at 04:50 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 unsettled to active on July 10. Solar wind speed at SOHO ranged between 351 and 478 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 117.9 (increasing 19.0 over the last solar rotation). The Potsdam WDC planetary A index was 26 (STAR Ap - based on the mean of three hour interval ap indices: 25.9). Three hour interval K indices: 44444443 (planetary), 55453343 (Boulder).

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

At 15h UTC the visible solar disk had 7 spotted active regions (in 2K resolution SDO images).

Region 11785 [S12W46] decayed further and was mostly quiet.
Region 11787 [S14W22] decayed slowly and produced a few C flares.

Spotted regions not numbered by SWPC:
S2534 [N17W01] was quiet and stable.
S2536 [S28W09] reemerged with a few spots.
New region S2539 [S18E78] rotated into view.
New region S2540 [N12E28] emerged with a penumbra spot.
New region S2541 [N05E84] rotated into view.

Coronal mass ejections (CMEs)

July 8, 10: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
July 9: A filament eruption in the northern central hemisphere began near 14h UTC and was associated with a faint full halo CME.

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 11 and quiet to active on July 12-13 due to effects from the July 9 CME.

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
11783 2013.06.29
2013.06.30
      N07W87          

plage

11785 2013.07.01 39 88 25 S13W43 0320 EKC EAI beta-gamma
11788 2013.07.01
2013.07.05
      S15W52           merged with AR 11787
S2523 2013.07.02       S23W41            
11787 2013.07.02
2013.07.03
17 36 16 S12W24 0120 EAI EAO beta-gamma

location: S14W22

S2525 2013.07.02       N11W37         plage
S2526 2013.07.02       N05W43           plage
11789 2013.07.06
2013.07.07
      S23W19         plage
11790 2013.07.06
2013.07.07
      S15E03           plage
S2534 2013.07.06   7   N17W01     BXO images/AR_S2534_20130710_2345.jpg images/AR_S2534_20130709_2345.jpg  
S2536 2013.07.07   2 2 S28W09 0012   CRO   plage
S2537 2013.07.07       N22E09           plage
S2538 2013.07.09       S17W48            
S2539 2013.07.10   2 1 S18E78 0020   BXO    
S2540 2013.07.10   1 1 N12E28 0004   AXX    
S2541 2013.07.10   1   N05E84 0010   AXX    
Total spot count: 56 137 45  
Sunspot number: 76 207 95  (total spot count + 10 * number of spotted regions)
Weighted SN: 71 155 63  (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): 46 72 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
2012.04 113.0 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) 12.60
2013.07 124.2 (1) 34.3 (2A) / 106.3 (2B) / 61.5 (2C) (58.0 projected, +0.1) (8.96)

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.