Solar Terrestrial Activity Report

Activity chart

Last major update issued on October 30, 2013 at 05:30 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, 2013)] [Cycle 24 progress (last update October 1, 2013) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update October 1, 2013)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update October 1, 2013)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update October 9, 2013)]

[POES auroral activity level since October 2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated October 10, 2013]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was quiet on October 29. Solar wind speed at SOHO ranged between 271 and 406 km/s. A weak solar wind shock was observed at SOHO at 09:35 UTC, probably the arrival of the CME observed on October 26.

Solar flux measured at 20h UTC on 2.8 GHz was 152.6 (increasing 44.5 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 117.4. The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.0). Three hour interval K indices: 00021122 (planetary), 10032222 (Boulder).

The background x-ray flux was at the class B8 level.

At the time of counting spots (see image time) spots were observed in 11 active regions in 2K resolution (SN: 225) and 9 active regions in 1K resolution (SN: 161) SDO images on the visible solar disk.

(Region 11875 rotated out of view and continued to be active while at the west limb. C5+ flares: C6.3 at 10:07, C9.3 at 18:31, X2.3 ar 21:54 UTC. At least a partial halo CME was observed after the X flare.)

Region 11877 [S13W70] decayed slowly and quietly.
Region 11879 [S13W55] developed slowly and was quiet.
Region 11882 [S11E08] decayed with the trailing penumbra fragmenting.

Region 11883 [N02E34] was quiet and stable (this is actually a southern hemisphere region).
Region 11884 [S13E40] developed further and has at least 2 magnetic delta structures. Major flares are possible.
New region 11886 [N14W09] emerged on October 28 and was numbered by SWPC the next day.

Spotted regions not numbered by SWPC:
S2784 [S17W04] decayed slowly and quietly.
New region S2788 [N30W45] emerged with a penumbra spot early in the day.
New region S2789 [N02E08] emerged with a penumbra spot.
New region S2790 [N20E78] emerged near the northeast limb.
New region S2791 [N13E08] emerged with a penumbra spot.

Coronal mass ejections (CMEs)

October 27: The CMEs originating in AR 11875 does not appear to be Earth directed.
October 28: A partial halo CME was observed in LASCO imagery after the X1 flare early in the day. The CME could reach Earth on October 30 or 31. A full halo CME was observed after an M4.4 event in AR 11882 and could reach Earth on October 30 or 31.
October 29: A partial halo CME was observed after the X2 flare in AR 11875 at the west limb.

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 coronal hole (CH592) will rotate into an Earth facing positon on October 31-November 3. The coronal hole has a narrow and elongated shape in its western section.

Coronal hole map

Propagation

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

Forecast

The geomagnetic field is expected to be quiet to minor storm on October 30-31 due to CME effects and quiet to unsettled on November 1.

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: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% 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 STAR SDO SWPC STAR Current Previous
2K 1K
11875 2013.10.16
2013.10.17
10     N06W92 0420 EKC     rotated out of view
11877 2013.10.18 9 5 4 S12W71 0310 DKO CAO area: 0230
11879 2013.10.21 2 10 4 S12W56 0080 CAO DAO

 

11881 2013.10.22
2013.10.24
      S22W34           plage
S2776 2013.10.22       N08W57           plage
11882 2013.10.23
2013.10.24
34 34 22 S09E07 0360 DKC DKC

location: S11E08

S2780 2013.10.24       S10W19           plage
S2781 2013.10.25       N26W04           plage
11883 2013.10.26 2 4 2 N03E31 0010 HRX CRO location: N02E34
11884 2013.10.26 22 38 25 S13E38 0340 EKC EKC beta-gamma-delta

area: 0650

location: S13E40

11885 2013.10.26 6     S17E35 0190 CAO       part of AR 11884
S2784 2013.10.27   3 2 S17W04 0010   BXO  
S2786 2013.10.27       N07W21           plage
11886 2013.10.28
2013.10.29
6 17 10 N14W09 0010 CRO DAI  
S2788 2013.10.29   1   N30W45 0003   AXX    
S2789 2013.10.29   1 1 N02E08 0007   AXX    
S2790 2013.10.29   1 1 N20E78 0005   AXX    
S2791 2013.10.29   1   N13E08 0002   AXX    
Total spot count: 91 115 71  
Sunspot number: 171 225 161  (total spot count + 10 * number of spotted regions)
Weighted SN: 147 153 109  (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): 103 79 89 k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for STAR SDO 2K, k = 0.55 for STAR SDO 1K

Monthly solar cycle data

Month Average measured solar flux International sunspot number (SIDC) Smoothed sunspot number Average ap
(3)
2011.11 153.5 (cycle peak) 96.7 (cycle peak) 61.1 (+1.2) 5.55
2012.02 106.5 32.9 66.9 (+1.4)
likely cycle 24 max
8.81
2012.06 119.6 64.5 58.9 (-2.8) 10.08
2012.07 133.9 66.5 57.8 (-1.1) 13.90
2012.08 115.4 63.0 58.2 (+0.4) 7.96
2012.09 122.9 61.4 58.1 (-0.1) 8.07
2012.10 123.3 53.3 58.6 (+0.5) 9.97
2012.11 121.3 61.8 59.7 (+1.1) 7.08
2012.12 108.6 40.8 59.6 (-0.1) 3.44
2013.01 127.1 62.9 58.7 (-0.9) 4.69
2013.02 104.3 38.0 58.4 (-0.3) 6.11
2013.03 111.3 57.9 57.5 (-0.9) 10.56
2013.04 124.8 72.4 (56.2 projected, -1.3) 5.40
2013.05 131.4 78.7 (55.8 projected, -0.4) 9.73
2013.06 110.1 52.5 (56.0 projected, +0.2) 12.60
2013.07 115.5 57.0 (56.1 projected, +0.1) 9.47
2013.08 114.6 66.0 (55.9 projected, -0.2) 8.27
2013.09 102.6 36.9 (55.4 projected, -0.5) 5.23
2013.10  131.4 (1) 118.8 (2A) / 127.0 (2B) / 75.3 (2C) (53.9 projected, -1.5) (7.54)

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 SIDC 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 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.