Solar Terrestrial Activity Report

Activity chart

Last major update issued on October 18, 2014 at 16:35 UTC. Updates will be irregular until October 27.

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

[Noon SDO sunspot count 1K Reference: 4K (large file) (updated daily)]

[POES auroral activity level October 2009 - December 2012]
[Solar polar fields vs solar cycles - updated October 11, 2014]
[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]

Recent activity

The geomagnetic field was quiet to unsettled on October 17. Solar wind speed at SOHO ranged between 361 and 473 km/s under the influence of a high speed stream from CH638.

Solar flux at 20h UTC on 2.8 GHz was 146 (increasing 26.9 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 133.6. The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.0). Three hour interval K indices: 23122123 (planetary), 14132322 (Boulder).

The background x-ray flux is at the class C1 level.

At the time of counting spots (see image time), spots were observed in 14 active regions using 2K resolution (SN: 229) and 12 active regions using 1K resolution (SN: 175) SDO images on the visible solar disk.

Region 12186 [S22W57] was quiet and stable.
Region 12187 [S09W00] was quiet and stable.
Region 12188 [N18W63] was quiet and stable.
Region 12189 [N21W19] was quiet and stable.
Region 12190 [N23E19] reemerged with penumbra spots.
Region 12191 [S12E16] developed slowly and quietly.
New region 12192 [S14E76] rotated partly into view on October 16 and was numbered by SWPC the next day. This is a large and complex region with a significant magnetic delta structure within the largest penumbra. An X class flare is possible.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3893 [N15W38] was quiet and stable.
S3900 [N07E20] was quiet and stable.
S3910 [S17E33] reemerged with penumbra spots.
New region S3915 [S24E31] emerged with a penumbra spot.
New region S3916 [S25E18] emerged with penumbra spots.
New region S3917 [N18W01] emerged with penumbra spots.
New region S3918 [N10W21] emerged with penumbra spots.

C2+ flares (GOES):

Magnitude Peak time (UTC) Location AR Comment
C3.9 03:20   12192  
C6.6 05:00   12192  
C3.6 12:49      
C6.7 15:39   12192  
C6.3 19:33   12192  
C2.3 21:12   12192  

Coronal mass ejections (CMEs)

October 15-17: 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]

A recurrent trans equatorial coronal hole (CH639) was in an Earth facing position on October 17-18. A recurrent trans equatorial coronal hole (CH640) will likely rotate into an Earth facing position on October 19-21.

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 fair to good.

Forecast

The geomagnetic field is expected to be quiet to unsettled on October 18-19. Quiet to active conditions are likely on October 20-24 due to effects from CH639 and CH640.

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
12186 2014.10.07 2 2 2 S20W57 0160 HSX HAX area: 0210

location: S22W57

12187 2014.10.11 1 13 9 S09W00 0200 HSX CHO area: 0320
S3893 2014.10.11   1 1 N15W38 0003   AXX  
12189 2014.10.11
2014.10.14
  6 2 N23W21 0007   AXX location: N21W19
S3898 2014.10.12       S20W33           plage
12188 2014.10.13   2   N18W70 0004   AXX

location: N18W63

S3900 2014.10.13   4 2 N07E20 0010   BXO  
12191 2014.10.14
2014.10.15
  12 6 S14E16 0025   AXX location: S12E16
12190 2014.10.14   7 5 N22E19 0015   BXO  
S3904 2014.10.14       N16W54           plage
S3905 2014.10.15       S15W21           plage
S3906 2014.10.15       N21W53           plage
S3908 2014.10.15       N09W22           plage
S3910 2014.10.16   5 3 S17E33     AXX    
12192 2014.10.16
2014.10.17
6 30 22 S13E68 0260 DKI FKC beta-gamma-delta

location: S14E76

area: 1900

S3912 2014.10.16       S29W24         plage
S3913 2014.10.16       S23W37         plage
S3914 2014.10.16       N05E39         plage
S3915 2014.10.17   1 1 S24E31 0002   AXX    
S3916 2014.10.17   2 1 S25E18 0007   AXX    
S3917 2014.10.17   2   N18W01 0004   BXO    
S3918 2014.10.17   2 1 N18W01 0006   BXO    
Total spot count: 9 89 55  
Sunspot number: 39 229 175  (total spot count + 10 * number of spotted regions)
Weighted SN: 29 114 80  (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): 23 80 96 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
2013.06 110.1 113.7 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) 78.4 (+1.1) 10.70
2014.03 149.9 148.5 91.9 80.8 (+2.4) 4.88
2014.04 143.9 144.8 84.7 (82.7 projected, +1.9) 7.88
2014.05 129.7 132.9 75.2 (82.3 projected, -0.4) 5.75
2014.06 122.0 125.8 71.0 (81.1 projected, -1.2) 6.72
2014.07 137.4 141.8 72.5 (79.4 projected, -1.7) 4.50
2014.08 124.7 127.9 74.7 (77.1 projected, -2.3) 7.71
2014.09 146.2   87.6 (73.8 projected, -3.3) 9.78
2014.10 127.9 (1)   43.3 (2A) / 78.9 (2B) / 81.7 (2C) (71.4 projected, -2.4) (7.2)

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.