Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 19, 2014 at 04:45 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update August 1, 2014)] [Cycle 24 progress (last update August 13, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update August 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update August 1, 2014)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update August 9, 2014)]

[POES auroral activity level October 2009 - December 2012]
[Solar polar fields vs solar cycles - updated July 18, 2014]
[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]

Recent activity

The geomagnetic field was quiet on August 18. Solar wind speed at SOHO ranged between 282 and 326 km/s.

Solar flux at 20h UTC on 2.8 GHz was 111 (increasing 18.4 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 130.0. The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.9). Three hour interval K indices: 11201111 (planetary), 11201221 (Boulder).

The background x-ray flux is at the class B2 level.

At the time of counting spots (see image time), spots were observed in 12 active regions using 2K resolution (SN: 198) and 8 active regions using 1K resolution (SN: 109) SDO images on the visible solar disk.

Region 12139 [N14W25] decayed slowly and was mostly quiet.
Region 12141 [N17E07] decayed slowly and quietly.
Region 12142 [N07E03] was quiet and stable.
Region 12143 [S04E02] was quiet and stable.
Region 12144 [S17W73] was quiet and stable.
Region 12146 [N08E49] was quiet and stable.
Region 12147 [S10E62] was mostly quiet and stable.

Spotted regions not numbered (or interpreted differently) by SWPC:
New region S3745 [N07W76] emerged with a penumbra spot.
New region S3746 [N20E43] emerged with a penumbra spot.
New region S3747 [N13E38] emerged with a penumbra spot.
New region S3748 [S10W36] emerged with a penumbra spot.
New region S3749 [S29W20] emerged with a penumbra spot.

C2+ Flares (GOES):

Magnitude Peak time (UTC) Location AR
       

Coronal mass ejections (CMEs)

August 16-18: 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.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is poor to fair.

Forecast

The geomagnetic field is expected to be quiet on August 19-21.

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: 0-30% probability, Yellow: 30-70% probability, Red: 70-100% 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 Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
12139 2014.08.10
2014.08.11
9 17 4 N13W24 0060 CSO CAO  
12144 2014.08.11
2014.08.14
3 4 2 S17W73 0180 DAO DAO area: 0360
12143 2014.08.13
2014.08.14
3 16 7 S05E04 0020 CAO DRI  
12142 2014.08.13
2014.08.14
  2 1 N05W03 0004   AXX location: N07E03
12141 2014.08.13
2014.08.14
13 23 11 N16E08 0100 ESI ESI area: 0150
S3734 2014.08.13       N22W39           plage
S3736 2014.08.14       S20W36           plage
12145 2014.08.14
2014.08.15
      S27W27           plage
12146 2014.08.16 1 4 1 N10E48 0090 HAX HSX area: 0200
S3741 2014.08.16       N13E25         plage
S3742 2014.08.16       N26W42           plage
S3743 2014.08.16       S21W44           plage
12147 2014.08.17 3 7 2 S09E61 0060 HAX CAO area: 0110
S3745 2014.08.18   1   N07W76 0002   AXX    
S3746 2014.08.18   1   N20E43 0002   AXX    
S3747 2014.08.18   1 1 N13E38 0003   AXX    
S3748 2014.08.18   1   S10W36 0001   AXX    
S3749 2014.08.18   1   S29W20 0002   AXX    
Total spot count: 32 78 29  
Sunspot number: 92 198 109  (total spot count + 10 * number of spotted regions)
Weighted SN: 62 106 57  (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): 55 69 60 k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for MSN 2K, k = 0.55 for MSN 1K (MSN=Magnetic Sunspot Number)

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number Average ap
(3)
Measured 1 AU
2013.04 124.8 125.9 72.4 57.9 (+0.4) 5.40
2013.05 131.4 134.3 78.7 59.9 (+2.0) 9.73
2013.06 110.1 113.7 52.5 62.6 (+2.7) 12.60
2013.07 115.5 119.3 57.0 65.5 (+2.9) 9.47
2013.08 114.6 118.3 66.0 69.0 (+3.5) 8.27
2013.09 102.6 103.7 36.9 73.1 (+4.1) 5.23
2013.10  132.1 131.2 85.6 75.0 (+1.9) 7.71
2013.11  148.3 145.1 77.6 75.4 (+0.4) 5.68
2013.12 147.7 143.1 90.3 76.0 (+0.6) 4.68
2014.01 157.4 152.4 81.8 77.3 (+1.3) 5.44
2014.02 170.3
(cycle peak)
166.3 102.3 (cycle peak) (78.1 projected, +0.8) 10.70
2014.03 149.9 148.5 91.9 (79.0 projected, +0.9) 4.88
2014.04 143.9 144.8 84.7 (78.1 projected, -0.9) 7.88
2014.05 129.7 132.9 75.2 (75.6 projected, -2.5) 5.75
2014.06 122.0 125.8 71.0 (72.9 projected, -2.7) 6.72
2014.07 137.4 141.8 72.5 (69.9 projected, -3.0) 4.5
2014.08 124.3 (1)   65.2 (2A) / 112.3 (2B) / 73.3 (2C) (66.5 projected, -3.4) (5.8)

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 WDC-SILSO 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 GFZ 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.