Solar Terrestrial Activity Report

Activity chart

Last major update issued on October 25, 2014 at 05:40 UTC.

[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 24. Solar wind speed at SOHO ranged between 388 and 500 km/s under the influence of a high speed stream from CH640.

Solar flux at 20h UTC on 2.8 GHz was 218 (increasing 37 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 140.8. The Potsdam WDC planetary A index was 9 (STAR Ap - based on the mean of three hour interval ap indices:8.9). Three hour interval K indices: 31122322 (planetary), 21233423 (Boulder).

The background x-ray flux is at the class C2 level.

At the time of counting spots (see image time), spots were observed in 9 active regions using 2K resolution (SN: 323) and 7 active regions using 1K resolution (SN: 184) SDO images on the visible solar disk.

Region 12192 [S14W17] again became less compact with the main penumbral areas separating. The region has a few small magnetic delta structures and one significant in the eastern part of the large trailing penumbra. Further X class flares are possible until the region rotates out of view in about 6 days.
Region 12193 [N05W59] decayed slowly and quietly.
Region 12194 [S13E19] decayed slowly and quietly.
Region 12195 [N07E48] was quiet and stable.
New region 12196 [S03E68] rotated into view on October 23 and was numbered by SWPC the next day.
New region 12197 [S12E64] rotated into view on October 23 and received its NOAA number the following day.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3921 [N20W37] decayed slowly and quietly.
S3930 [N10E22] was quiet and stable.
New region S3935 [N12W52] emerged with penumbra spots.

C2+ flares (GOES):

Magnitude Peak time (UTC) Location AR Comment
C4.2 02:39 S20W02 12192  
C3.4 03:00 S20W02 12192  
C3.6 04:00 S22W00 12192  
M4.0 07:48   12192 small CME
C3.6 10:01   12192  
C5.1 (LDE) 15:06   12192  
X3.1 (LDE) 21:41   12192 no CME

Coronal mass ejections (CMEs)

October 22-24: 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 (CH640) was in an Earth facing position on October 19-22.

Propagation

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

Forecast

The geomagnetic field is expected to be quiet to unsettled on October 25 due to lingering effects from CH640 and quiet on October 26-27.

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
12187 2014.10.11 1     S08W93 0070 HAX     rotated out of view
12191 2014.10.14
2014.10.15
      S11W79         plage
12190 2014.10.14       N22W79           plage
S3910 2014.10.16       S17W58           plage
12192 2014.10.16
2014.10.17
62 177 89 S12W21 2510 FKC FKC beta-gamma-delta

location: S14W17

area: 3440

S3914 2014.10.16       N05W52           plage
12193 2014.10.18
2014.10.19
3 5 4 N07W59 0070 CAO CSO area: 0200
S3921 2014.10.19   2   N20W37 0004   AXX  
12194 2014.10.19
2014.10.21
3 15 6 S12E19 0070 CAO CAO area: 0140
S3925 2014.10.21       S17W49         plage
12195 2014.10.21
2014.10.22
6 25 12 N08E47 0070 CSO ESI area: 0120
S3930 2014.10.22   3   N10E22 0006   AXX  
S3931 2014.10.22       N13W26           plage
S3932 2014.10.23       N03W10         plage
12197 2014.10.23
2014.10.24
1 3 1 S12E62 0010 AXX HRX  
12196 2014.10.23
2014.10.24
1 1 1 S03E66 0020 HSX HSX area: 0040
S3935 2014.10.24   2 1 N12W52 0008   BXO    
Total spot count: 77 233 114  
Sunspot number: 147 323 184  (total spot count + 10 * number of spotted regions)
Weighted SN: 112 266 147  (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): 88 113 101 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
2014.10 148.0 (1)   67.6 (2A) / 87.3 (2B) / 88.6 (2C) (71.4 projected, -2.4) (8.7)

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.