Solar Terrestrial Activity Report

Activity chart

Last major update issued on October 4, 2014 at 06:55 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 September 6, 2014)]

[New: Noon SDO count 1K 4K (large file)]

[POES auroral activity level October 2009 - December 2012]
[Solar polar fields vs solar cycles - updated September 6, 2014]
[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]

Recent activity

The geomagnetic field was quiet on October 3. Solar wind speed at SOHO ranged between 345 and 425 km/s. The total field of the interplanetary magnetic field has become moderately strong early on October, probably due to the passage of a magnetic cloud.

Solar flux at 20h UTC on 2.8 GHz was 137 (decreasing 20.1 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 137.0. The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.1). Three hour interval K indices: 21111111 (planetary), 21111210 (Boulder).

The background x-ray flux is at the class B7 level.

At the time of counting spots (see image time), spots were observed in 14 active regions using 2K resolution (SN: 247) and 10 active regions using 1K resolution (SN: 157) SDO images on the visible solar disk.

Region 12176 [N07W67] decayed slowly and quietly.
Region 12177 [N12W25] decayed slowly and quietly.
Region 12178 [S02W08] decayed slowly and was quiet.
Region 12179 [S12E06] decayed slowly and quietly.
Region 12181 [S12W15] developed gaining spots and penumbral area.
New region 12182 [S13E25] emerged on October 1 and was numbered by SWPC two days later.
New region 12183 [N13E57] rotated into view on October 1 with SWPC noticing the region two days later.
New region 12184 [S19E67] rotated into view on October 2 and got its NOAA number the next day.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3858 [N04E05] was quiet and stable.
S3861 [N13W15] decayed slowly and quietly.
S3866 [S04E07] decayed slowly and quietly.
S3872 [N09W54] was quiet and stable.
New region S3875 [N12E33] was observed with penumbra spots.
New region S3877 [S29W39] emerged with a penumbra spot.

C2+ flares (GOES):

Magnitude Peak time (UTC) Location AR Comment
C3.2 00:08   12172  
C5.7 03:04   12173  
C5.7 04:20   12172  
C9.0 06:48   12173  
C2.2 10:46   12181  
C2.5 11:48   12172  

Coronal mass ejections (CMEs)

October 1-3: 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]

No obvious coronal holes are currently in or near Earth facing positions.

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 poor to fair.

Forecast

The geomagnetic field is expected to be quiet to unsettled with a chance of active intervals on October 4 and quiet on October 5-6.

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
12172 2014.09.20 1     S08W91 0010 AXX    

rotated out of view

12176 2014.09.22
2014.09.25
5 6 4 N08W66 0040 CAO DAO  
12177 2014.09.25 6 8 5 N13W27 0010 AXX AXX

 

S3848 2014.09.25       S16W39           plage
12178 2014.09.27 10 22 18 S01W08 0160 CAI DAI  
12179 2014.09.27
2014.09.28
2 9 5 S11E04 0020 HAX CRO  
S3858 2014.09.27   6 4 N04E05 0012   BXO  
S3859 2014.09.27       N11W39           plage
S3861 2014.09.27   5 2 N13W15 0010   AXX  
12181 2014.09.28
2014.09.30
7 25 12 S11W17 0030 DRO DAI  

area: 0100

location: S12W15

S3863 2014.09.28       S18W57           plage
S3864 2014.09.29       S07W47           plage
S3866 2014.09.29   4   S04E07 0007   AXX  
12180 2014.09.29
2014.09.30
      N13W55           plage
S3868 2014.09.30       S24W23           plage
12182 2014.10.01
2014.10.03
5 12 5 S13E25 0020 CSO DAO  
12183 2014.10.01
2014.10.03
1 4 1 N13E54 0010 AXX CRO  
S3871 2014.10.01       S32W11           plage
S3872 2014.10.02   2   N09W54 0004   AXX  
12184 2014.10.02
2014.10.03
1 1 1 S18E66 0010 HRX HRX  
S3874 2014.10.02       S08E14           plage
S3875 2014.10.03   2   N12E33     AXX    
S3877 2014.10.03   1   S29W39     AXX   plage
Total spot count: 38 107 57  
Sunspot number: 128 247 157  (total spot count + 10 * number of spotted regions)
Weighted SN: 64 136 86  (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): 77 86 86 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) 9.6
2014.10 142.3 (1)   16.8 (2A) / 130.5 (2B) / 97.4 (2C) (71.4 projected, -2.4) (6.2)

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.