Solar Terrestrial Activity Report

Activity chart

Last major update issued on October 3, 2014 at 04:35 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 2. Solar wind speed at SOHO ranged between 345 and 435 km/s, weakly under the influence of a low speed stream from CH637.

Solar flux at 20h UTC on 2.8 GHz was 149 (increasing 5.1 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 137.7. The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 7.6). Three hour interval K indices: 22222222 (planetary), 12222322 (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 14 active regions using 2K resolution (SN: 248) and 12 active regions using 1K resolution (SN: 182) SDO images on the visible solar disk.

Region 12172 [S10W78] rotated partly out of view. M class flares are possible today.
Region 12176 [N07W52] was quiet and stable.
Region 12177 [N13W12] decayed slowly and quietly.
Region 12178 [S02E05] was quiet with some decay observed in the trailing spot section.
Region 12179 [S11E18] decayed slowly and quietly.
Region 12181 [S12W02] decayed slowly and quietly.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3858 [N05E19] was quiet and stable.
S3861 [N12W03] decayed slowly and quietly.
S3866 [S05E19] was quiet and stable.
S3869 [S13E40] developed slowly and quietly.
S3870 [N13E69] was quiet and stable.
New region S3872 [N09W40] emerged early in the day with a couple of penumbra spots, then decayed slowly.
New region S3873 [S19E80] rotated into view with a single small spot.
New region S3874 [S08E27] emerged with a penumbra spot.

C2+ flares (GOES):

Magnitude Peak time (UTC) Location AR Comment
M1.5 (LDE) 17:44 S18W76 12173  
M7.3/1F 19:01 S17W82 12173 CME
C3.6 22:54   12173  

Coronal mass ejections (CMEs)

September 30 - October 2: 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.

Forecast

The geomagnetic field is expected to be mostly quiet on October 3-5.

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
12173 2014.09.19
2014.09.20
1     S13W85 0050 HAX    

rotated out of view

12172 2014.09.20 4 1 1 S08W82 0150 ESO HAX

location: S10W78

12176 2014.09.22
2014.09.25
6 11 7 N09W52 0030 DRO DAO area: 0100

location: N07W52

12177 2014.09.25 9 20 9 N12W11 0030 CSO DAO

area: 0090

S3848 2014.09.25       S16W26         plage
S3850 2014.09.26       S16W53           plage
12178 2014.09.27 12 26 17 S02E05 0140 DAI DSI area: 0280
12179 2014.09.27
2014.09.28
1 13 9 S10E15 0020 HAX CRI area: 0040

location: S11E18

S3858 2014.09.27   2   N05E19 0005   BXO  
S3859 2014.09.27       N11W26           plage
S3861 2014.09.27   3 2 N12W03 0010   AXX  
12181 2014.09.28
2014.09.30
2 10 5 S11W05 0010 BXO CRO location: S12W02
S3863 2014.09.28       S18W44           plage
S3864 2014.09.29       S07W34           plage
S3866 2014.09.29   8 3 S05E19 0016   AXX  
12180 2014.09.29
2014.09.30
      N13W41           plage
S3868 2014.09.30       S24W10           plage
S3869 2014.10.01   10 6 S13E40 0040   DRI  
S3870 2014.10.01   1 1 N13E69 0013   AXX  
S3871 2014.10.01       S32E02         plage
S3872 2014.10.02   1 1 N09W40 0003   AXX    
S3873 2014.10.02   1 1 S19E80 0010   AXX    
S3874 2014.10.02   1   S08E27 0002   AXX    
Total spot count: 35 108 62  
Sunspot number: 105 248 182  (total spot count + 10 * number of spotted regions)
Weighted SN: 63 137 91  (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): 63 87 100 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
2014.10 152 (1)   8.7 (2A) / 134.5 (2B) / 96.8 (2C) (71.4 projected, -2.4) (8.1)

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.