Solar Terrestrial Activity Report

Activity chart

Last major update issued on November 3, 2013 at 05:00 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update November 2, 2013)] [Cycle 24 progress (last update November 2, 2013) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update November 2, 2013)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update November 2, 2013)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update November 3, 2013)]

[POES auroral activity level since October 2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated November 2, 2013]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was quiet on November 2. Solar wind speed at SOHO ranged between 285 and 424 km/s. A sudden increase in solar wind speed and temperature was observed at ACE near 20h. This was likely the arrival of the CME observed on October 30 after the X2 limb event.

Solar flux measured at 20h UTC on 2.8 GHz was 141.6 (increasing 35.1 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 118.7. The Potsdam WDC planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 2.5). Three hour interval K indices: 11010001 (planetary), 12111201 (Boulder).

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

At the time of counting spots (see image time) spots were observed in 9 active regions in 2K resolution (SN: 211) and 9 active regions in 1K resolution (SN: 151) SDO images on the visible solar disk.

Region 11882 [S10W48] decayed slowly and quietly.
Region 11884 [S15W12] decayed slowly and has a weakening magnetic delta structure in a central northern penumbra. Further M class flaring is possible. C5+ flares: impulsive M1.6/1F at 22:21 UTC.
Region 11887 [N19E23] was quiet and stable.
Region 11888 [S13W60] decayed slowly and quietly.
New region 11889 [S19E22] emerged quickly and has polarity intermixing. C flares are possible.
New region 11890 [S11E78] rotated fully into view revealing a large, compact region. Major flares are possible.

Spotted regions not numbered by SWPC:
S2798 [S23W14] was mostly unchanged. C5+ flares: C8.2 at 04:46 UTC.
New region S2800 [S08E60] emerged with penumbra spots.
New region S2802 [S11E12] emerged with penumbra spots.

Coronal mass ejections (CMEs)

October 31-November 1: No obviously Earth directed CMEs were observed in LASCO or STEREO imagery.
November 2: A full halo CME was observed after 05h UTC, its source was backsided in a northern hemisphere active region (near the equator). Another impressive CME was observed later in the day after another backsided flare.

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.

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. Propagation on long distance northeast-southwest paths is fair.

Forecast

The geomagnetic field is expected to be quiet to unsettled on November 3 due to CME effects. Quiet to unsettled is likely on November 4-6 due to effects from CH592.

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
11882 2013.10.23
2013.10.24
4 8 6 S10W46 0110 CAO CAO

 

S2781 2013.10.25       N26W56           plage
11883 2013.10.26       N04W27           plage

location: N02W21

11884 2013.10.26 21 41 20 S12W13 0250 EKO EAC beta-gamma-delta

area: 0400

location: S15W12

11885 2013.10.26 12     S19W16 0160 CAO       part of AR 11884
11888 2013.10.27
2013.10.31
3 6 3 S14W60 0020 CRO CRO  
11886 2013.10.28
2013.10.29
      N14W64           plage
S2789 2013.10.29       N02W46         plage
11887 2013.10.29
2013.10.30
4 9 6 N20E22 0020 CRO CRO

location: N19E23

area: 0030

S2791 2013.10.29       N13W31           plage
S2792 2013.10.30       S10E33           plage
S2793 2013.10.30       N19W52           plage
S2796 2013.10.31       N05E45           plage
S2797 2013.10.31       S05W18         plage
S2798 2013.11.01   10 4 S23W14 0030   BXO  
11890 2013.11.01
2013.11.02
3 15 8 S09E74 0120 HSX EKC beta-gamma

area: 1100

location: S11E78

11889 2013.11.02 6 24 10 S18E23 0030 CRO DRI   beta-gamma

area: 0060

S2800 2013.11.02   5 2 S08E60 0012   BXO    
S2802 2013.11.02   3 2 S11E12 0012   CRO    
Total spot count: 53 121 61  
Sunspot number: 123 211 151  (total spot count + 10 * number of spotted regions)
Weighted SN: 87 155 95  (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): 74 74 83 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
2012.07 133.9 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 57.9 (+0.4) 5.40
2013.05 131.4 78.7 (59.3 projected, +1.4) 9.73
2013.06 110.1 52.5 (59.7 projected, +0.4) 12.60
2013.07 115.5 57.0 (60.0 projected, +0.3) 9.47
2013.08 114.6 66.0 (60.3 projected, +0.3) 8.27
2013.09 102.6 36.9 (60.2 projected, -0.1) 5.23
2013.10  132.1 85.6 (58.7 projected, -1.5) 7.65
2013.10  143.6 (1) 7.3 (2A) / 114.0 (2B) / 81.0 (2C) (56.6 projected, -2.1) (3.4)

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.