Solar Terrestrial Activity Report

Activity chart

Last major update issued on October 28, 2014 at 05:25 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 27. Solar wind speed at SOHO ranged between 359 and 545 km/s. Another geomagnetic disturbance began late in the day.

Solar flux at 20h UTC on 2.8 GHz was 188 (increasing 26 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 143.1. The Potsdam WDC planetary A index was 12 (STAR Ap - based on the mean of three hour interval ap indices: 11.6). Three hour interval K indices: 32232224 (planetary), 22333423 (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: 229) and 6 active regions using 1K resolution (SN: 134) SDO images on the visible solar disk.

Region 12192 [S15W55] still has a strong magnetic delta in the western section of the largest penumbra. The region is slowly losing area and spots. Further major flares are likely.
Region 12194 [S12W20] decayed slowly and quietly.
Region 12195 [N07E07] decayed slowly and quietly.
Region 12196 [S04E28] decayed slowly and quietly.
Region 12197 [S13E27] decayed slowly and has minor polarity intermixing.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3937 [S16E17] was quiet and stable.
New region S3940 [S16E65] rotated into view with a penumbra spot.
New region S3941 [S15E42] emerged with penumbra spots.
New region S3942 [S15W04] emerged with a penumbra spot.

C2+ flares (GOES):

Magnitude Peak time (UTC) Location AR Comment
M7.1/3B 00:34 S14W44 12192  
M1.0 02:02   12192  
M1.3 03:41   12192  
C3.4 05:04   12192  
C4.9 05:38   12192  
C9.6 07:01   12192  
C9.6 07:15   12192  
M2.0 09:40   12192  
M6.7/2B 10:09   12192  
M1.8 10:54   12192  
X2.0/2B (LDE) 14:47 S17W52 12192  
M1.4 17:40   12192  
C5.4 21:23   12192  
C4.6 23:04   12192  

Coronal mass ejections (CMEs)

October 25-27: 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 northern hemisphere coronal hole (CH641) will likely rotate acrosss the central meridian on October 29-30.

Propagation

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

Forecast

The geomagnetic field is expected to be quiet to active on October 28 and quiet to unsettled on October 30.

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
51 81 52 S12W59 2380 FKC FKC beta-gamma-delta

location: S15W55

12194 2014.10.19
2014.10.21
2 11 3 S12W23 0040 HAX CAO area: 0070

location: S12W20

12195 2014.10.21
2014.10.22
9 21 7 N07E04 0080 CSI CSO location: N07E07
S3930 2014.10.22       N07W23         plage
S3931 2014.10.22       N16W49           plage
S3932 2014.10.23       N03W49           plage
12197 2014.10.23
2014.10.24
7 18 9 S13E25 0020 CRI BXI  
12196 2014.10.23
2014.10.24
1 2 2 S04E26 0010 HAX HRX  
S3936 2014.10.25       S29W14           plage
S3937 2014.10.25   2   S14E17 0003   AXX  
S3939 2014.10.26       N09W47         plage
S3940 2014.10.27   1   S16E65 0002   AXX    
S3941 2014.10.27   2   S15E42 0003   BXO    
S3942 2014.10.27   1 1 S15W04 0003   AXX    
Total spot count: 70 139 74  
Sunspot number: 120 229 134  (total spot count + 10 * number of spotted regions)
Weighted SN: 98 162 97  (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): 72 80 74 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
2014.10 154.7 (1)   75.8 (2A) / 91.4 (2B) / 85.1 (2C) (71.4 projected, -2.4) (8.9)

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.