Solar Terrestrial Activity Report

Activity chart

Last major update issued on October 26, 2014 at 05:55 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 active on October 25. Solar wind speed at SOHO ranged between 356 and 444 km/s under the influence of effects from CH640.

Solar flux at 20h UTC on 2.8 GHz was 219 (increasing 38 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 141.8. The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.3). Three hour interval K indices: 43222222 (planetary), 32223422 (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 12 active regions using 2K resolution (SN: 325) and 9 active regions using 1K resolution (SN: 198) SDO images on the visible solar disk.

Region 12192 [S14W30] lost some area and a few spots with the main penumbral areas drifting slowly apart. Although there are several small magnetic delta in the region, the only significant one is in the western part of the largest trailing penumbra. As long as this delta persists we can expect occasional major flares.
Region 12193 [N05W73] decayed slowly and quietly.
Region 12194 [S13E06] was quiet and stable.
Region 12195 [N07E33] was quiet and stable.
Region 12196 [S04E55] decayed slowly and quietly.
Region 12197 [S13E50] was quiet and stable.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3930 [N09E07] was quiet and stable.
S3931 [N16W23] reemerged with penumbra spots.
S3935 [N13W66] was quiet and stable.
New region S3936 [S29E12] emerged with a penumbra spot.
New region S3937 [S14E44] was observed with penumbra spots.
New region S3938 [N06W34] emerged with a penumbra spot.

C2+ flares (GOES):

Magnitude Peak time (UTC) Location AR Comment
C4.4 04:13 S07W24 12192  
C9.2/1F (LDE) 08:08 S14W23 12192  
C4.6 09:49   12192  
C3.2 12:20   12192  
C5.1 15:04   12192  
C9.7 15:52   12192  
X1.0/3B (LDE) 17:08 S16W31 12192  
C8.4 23:26   12192  

Coronal mass ejections (CMEs)

October 23-25: 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 26 due to lingering effects from CH640 and quiet on October 27-28.

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
12192 2014.10.16
2014.10.17
44 154 84 S12W34 2570 FKC FKC beta-gamma-delta

location: S14W30

area: 2800

12193 2014.10.18
2014.10.19
1 3 2 N06W74 0070 HAX HAX area: 0150
S3921 2014.10.19       N20W50         plage
12194 2014.10.19
2014.10.21
1 7 4 S12E05 0050 HAX CAO area: 0120
12195 2014.10.21
2014.10.22
7 19 10 N08E33 0090 DAI DSI area: 0140
S3930 2014.10.22   3 1 N09E07 0010   BXO  
S3931 2014.10.22   3 1 N16W23 0007   AXX    
S3932 2014.10.23       N03W23           plage
12197 2014.10.23
2014.10.24
1 7 4 S12E48 0010 AXX CRO location: S13E50

area: 0020

12196 2014.10.23
2014.10.24
1 2 1 S04E53 0020 HAX HAX location: S04E55
S3935 2014.10.24   2 1 N13W66 0005   BXO  
S3936 2014.10.25   1   S29E12 0002   AXX    
S3937 2014.10.25   3   S14E44 0007   AXX    
S3938 2014.10.25   1   N06W34 0001   AXX    
Total spot count: 55 205 108  
Sunspot number: 115 325 198  (total spot count + 10 * number of spotted regions)
Weighted SN: 85 238 141  (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): 69 114 109 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
2014.10 150.9 (1)   71.3 (2A) / 88.4 (2B) / 88.1 (2C) (71.4 projected, -2.4) (8.8)

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.