Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 20, 2014 at 04:20 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 to active on August 19. Solar wind speed at SOHO ranged between 292 and 449 km/s. A disturbance related to a full halo CME (source: central disk filament eruption) observed late on August 15 arrived at SOHO at 06:13 UTC.

Solar flux at 20h UTC on 2.8 GHz was 111 (increasing 11.9 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 130.0. The Potsdam WDC planetary A index was 11 (STAR Ap - based on the mean of three hour interval ap indices: 10.8). Three hour interval K indices: 11221234 (planetary), 11243345 (Boulder).

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

At the time of counting spots (see image time), spots were observed in 9 active regions using 2K resolution (SN: 182) and 9 active regions using 1K resolution (SN: 145) SDO images on the visible solar disk.

Region 12139 [N14W25] gained a few spots and was quiet.
Region 12141 [N17W08] decayed slowly and quietly.
Region 12142 [N08W09] developed slowly and quietly.
Region 12143 [S04W11] was quiet and stable.
Region 12144 [S17W84] rotated partly out of view.
Region 12146 [N08E36] gained spots and was mostly quiet.
Region 12147 [S10E48] was quiet and stable.

Spotted regions not numbered (or interpreted differently) by SWPC:
New region S3750 [N07E57] emerged with several spots and has polarity intermixing. C flares are possible.
New region S3751 [N15W67] emerged with a few spots.

C2+ Flares (GOES):

Magnitude Peak time (UTC) Location AR
       

Coronal mass ejections (CMEs)

August 17-19: 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 to unsettled on August 20 due to CME effects and quiet on August 21-22.

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
5 12 9 N14W39 0050 CAO DAO  
12144 2014.08.11
2014.08.14
2 1 1 S17W87 0100 DAO HSX  
12143 2014.08.13
2014.08.14
5 22 12 S04W12 0030 DRI DRI  
12142 2014.08.13
2014.08.14
  9 5 N05W18 0025   BXO location: N08W09
12141 2014.08.13
2014.08.14
9 16 10 N16W05 0080 ESI CAO area: 0120
S3734 2014.08.13       N22W52           plage
S3736 2014.08.14       S20W49           plage
12145 2014.08.14
2014.08.15
      S27W41           plage
12146 2014.08.16 1 10 5 N08E35 0150 HSX CAO area: 0230
S3741 2014.08.16       N13E12           plage
S3742 2014.08.16       N26W55           plage
S3743 2014.08.16       S21W57           plage
12147 2014.08.17 2 6 3 S10E46 0050 HAX HAX area: 0080
S3746 2014.08.18       N20E30         plage
S3747 2014.08.18       N13E25         plage
S3748 2014.08.18       S10W49         plage
S3749 2014.08.18       S29W33         plage
S3750 2014.08.19   13 8 N07E57 0050   DRI   beta-gamma
S3751 2014.08.19   3 2 N15W67 0012   CRO    
Total spot count: 24 92 55  
Sunspot number: 84 182 145  (total spot count + 10 * number of spotted regions)
Weighted SN: 52 126 89  (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): 50 64 80 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
2014.08 123.6 (1)   67.9 (2A) / 110.8 (2B) / 74.6 (2C) (66.5 projected, -3.4) (6.1)

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.