Solar Terrestrial Activity Report

Activity chart

Last major update issued on October 7, 2014 at 03:45 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 sunspot 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 to unsettled on October 6. Solar wind speed at SOHO ranged between 372 and 453 km/s.

Solar flux at 20h UTC on 2.8 GHz was 130 (decreasing 29.3 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 134.4. The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.5). Three hour interval K indices: 32111013 (planetary), 22002212 (Boulder).

The background x-ray flux is at the class B4 level.

At the time of counting spots (see image time), spots were observed in 10 active regions using 2K resolution (SN: 172) and 10 active regions using 1K resolution (SN: 137) SDO images on the visible solar disk.

Region 12178 [S01W50] decayed slowly and quietly.
Region 12181 [S12W60] decayed slowly and produced a few low level C class flares.
Region 12182 [S13W14] was quiet and stable.
Region 12183 [N13E14] was quiet and stable.
Region 12184 [S22E37] developed slowly as new flux emerged within the trailing polarity area.
New region 12185 [S13E47] emerged on October 5 and was numbered by SPWC the next day.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3858 [N05W35] was quiet and stable.
S3875 [N13W04] was quiet and stable.
S3878 [S20E09] was quiet and stable.
S3879 [N14E47] was quiet and stable.

C2+ flares (GOES):

Magnitude Peak time (UTC) Location AR Comment
C3.0 (LDE) 17:07 S16E60 12185  

Coronal mass ejections (CMEs)

October 4-6: 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 on October 7-9.

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
12177 2014.09.25       N13W68          

plage

12178 2014.09.27 3 5 3 S01W51 0100 HAX CAO area: 0150
12179 2014.09.27
2014.09.28
      S10W38           plage
S3858 2014.09.27   1 1 N05W35 0005   AXX  
S3861 2014.09.27       N13W54           plage
12181 2014.09.28
2014.09.30
7 12 6 S11W59 0080 DSI DAO  
S3866 2014.09.29       S06W47           plage
12182 2014.10.01
2014.10.03
11 17 11 S15W16 0090 DAI DAO  
12183 2014.10.01
2014.10.03
1 6 3 N13E16 0010 AXX BXO  
S3871 2014.10.01       S32W50           plage
12184 2014.10.02
2014.10.03
1 6 3 S17E26 0010 AXX DRO area: 0025

location: S22E37

S3874 2014.10.02       S08W25           plage
S3875 2014.10.03   2 1 N13W04 0006   AXX  
S3878 2014.10.04   7 2 S20E09 0015   BXO images/AR_S3878_20141006_2345.png  
S3879 2014.10.04   6 2 N14E47 0012   BXO  
12185 2014.10.05
2014.10.06
3 9 4 S14E43 0010 BXO BXO location: S13E47

area: 0020

Total spot count: 26 72 36  
Sunspot number: 86 172 136  (total spot count + 10 * number of spotted regions)
Weighted SN: 41 90 52  (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 60 75 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
2014.10 137.8 (1)   23.0 (2A) / 119.0 (2B) / 95.1 (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.