Solar Terrestrial Activity Report

Activity chart

Last major update issued on October 20, 2014 at 04:35 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 19. Solar wind speed at SOHO ranged between 320 and 508 km/s. A high speed stream from CH639 arrived after 17h UTC and caused an increase in geomagnetic activity early on October 20.

Solar flux at 20h UTC on 2.8 GHz was 173 (increasing 37.2 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 135.2. The Potsdam WDC planetary A index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 8.8). Three hour interval K indices: 33221121 (planetary), 33332332 (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 10 active regions using 2K resolution (SN: 268) and 10 active regions using 1K resolution (SN: 183) SDO images on the visible solar disk.

Region 12186 [S21W82] was quiet and stable.
Region 12187 [S09W27] was quiet and stable.
Region 12190 [N19E01] was quiet and stable.
Region 12191 [S12W09] was quiet and stable.
Region 12192 [S14E50] developed with new flux emerging to the northeast of the huge spot. The region can obviously produce X flares, there is a slight possibility of an X10+ event.
New region 12193 [N03E09] emerged on October 18 and was numbered by SWPC the next day. The region developed slowly on October 19 and could produce C flares.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3900 [N03W05] reemerged with a penumbra spot.
New region S3921 [N16E31] was observed with penumbra spots.
New region S3922 [S12E83] rotated into view.
New region S3923 [S18W38] emerged with a penumbra spot.

C2+ flares (GOES):

Magnitude Peak time (UTC) Location AR Comment
C5.7 (LDE) 01:47   12192  
X1.1/3F (LDE) 05:03 S13E57 12192 No significant CME
C4.2 11:19 S09E59 12192  
C5.8 12:14 S09E58 12192  
C3.9 15:56   12191?  
C4.7 17:34   12192  
C2.1 20:27   S3922  

Coronal mass ejections (CMEs)

October 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]

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.

Forecast

The geomagnetic field is expected to be quiet to active 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 1 1 1 S20W84 0100 HSX HSX area: 0150

location: S21W82

12187 2014.10.11 7 14 6 S09W27 0160 CSO CKO area: 0290
12189 2014.10.11
2014.10.14
      N23W49           plage
S3898 2014.10.12       S20W59           plage
S3900 2014.10.13   1 1 N03W05 0003   AXX    
12191 2014.10.14
2014.10.15
  4 2 S14W12 0010   BXO location: S12W09
12190 2014.10.14   3 2 N22W09 0010   BXO location: N19E01
S3905 2014.10.15       S15W47           plage
S3908 2014.10.15       N09W48           plage
S3910 2014.10.16       S17E07           plage
12192 2014.10.16
2014.10.17
32 117 56 S13E43 1560 FKC FKC beta-gamma-delta

location: S14E50

area: 2350

S3912 2014.10.16       S29W50           plage
S3913 2014.10.16       S23W50           plage
S3914 2014.10.16       N05E13           plage
S3915 2014.10.17       S24E05           plage
S3916 2014.10.17       S25W08           plage
S3917 2014.10.17       N18W27           plage
S3918 2014.10.17       N10W47           plage
12193 2014.10.18
2014.10.19
6 22 11 N05E10 0030 CRO DAI area: 0080

location: N03E09

S3920 2014.10.18       S05W35         plage
S3921 2014.10.19   4 2 N16E31 0010   BXO    
S3922 2014.10.19   1 1 S12E83 0120   HSX    
S3923 2014.10.19   1 1 S18W38 0004   AXX    
Total spot count: 46 168 83  
Sunspot number: 86 268 183  (total spot count + 10 * number of spotted regions)
Weighted SN: 69 203 118  (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): 52 94 101 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
2014.10 132.0 (1)   48.0 (2A) / 78.3 (2B) / 83.9 (2C) (71.4 projected, -2.4) (7.6)

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.