Last major update issued on October 18, 2013 at 02:55 UTC. Updates are likely to be irregular or very late until October 25.
[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)]
The geomagnetic field was quiet to unsettled on October 17. Solar wind speed at SOHO ranged between 376 and 470 km/s.
Solar flux measured at 20h UTC on 2.8 GHz was 136.1 (increasing 26.9 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 112.6. The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.1). Three hour interval K indices: 33222111 (planetary), 23433311 (Boulder).
The background x-ray flux is at the class B9 level.
At the time of counting spots (see image time) spots were observed in 13 active regions in 2K resolution (SN: 238) and 12 active regions in 1K resolution (SN: 178) SDO images on the visible solar disk.
Region 11861 [S08W68] merged with AR S2761. The
central part of the region is complex and a major (proton) flare is a distinct
possibility.
C5+ flares: C5.8 at 10:32, long duration M1.2 event
peaking at 15:41 UTC.
Region 11864 [S22W57] decayed quickly and quietly.
Region 11867 [N23W81] was quiet and stable.
Region 11869 [N20E07] was quiet and stable.
Region 11870 [S15W44] was quiet and stable.
Region 11872 [S17E42] was quiet and stable.
Region 11873 [N10E47] decayed slowly and quietly.
New region 11874 [S12E22] emerged on October 16 and was numbered by SWPC
the next day. The region developed quickly and could produce C flares.
New region 11875 [N06E72] rotated partly into view on October 16
and got its NOAA number the next day.
New region 11876 [N05W62] emerged on October 10 and was noticed by SWPC a
week later.
Spotted regions not numbered by SWPC:
S2753 [N17E22] was quiet and stable.
S2764 [N22W03] was quiet and stable.
New region S2767 [S05E53] emerged with a penumbra spot.
October 15-17: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
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 (CH591) in the northern hemisphere rotated across the central meridian on October 17. CH591 may be too far to the north to cause geomagnetic effects.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is poor to fair. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet to unsettled on October 18-21. There's a chance of weak coronal hole effects from CH591 on October 20-21.
| 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.
(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 | ||||||||||
| 11861 | 2013.10.06 2013.10.07 |
17 | 26 | 15 | S08W69 | 0370 | EKI | FKC |
 |
 |
area: 0800 merged with AR S2761 |
| 11864 | 2013.10.07 2013.10.08 |
1 | 9 | 4 | S23W60 | 0060 | HSX | CAO |
 |
 |
location: S22W57 |
| 11865 | 2013.10.08 | 4 | S21W50 | 0010 | BXO | part of AR 11864 | |||||
| 11867 | 2013.10.09 2013.10.10 |
1 | 2 | 2 | N23W83 | 0010 | AXX | BXO |
 |
 |
|
| 11876 | 2013.10.10 2013.10.17 |
2 | 4 | 2 | N05W62 | 0010 | BXO | BXO |
 |
 |
|
| 11868 | 2013.10.11 2013.10.13 |
N17W05 | |||||||||
| S2751 | 2013.10.11 | N24W50 | plage | ||||||||
| 11869 | 2013.10.12 2013.10.13 |
2 | 5 | 4 | N18E06 | 0020 | CSO | BXO |
 |
 |
location: N20E07 |
| S2753 | 2013.10.13 | 8 | 3 | N17E22 | 0040 | CSO |
 |
 |
|||
| 11870 | 2013.10.13 2013.10.14 |
1 | 8 | 2 | S13W49 | 0010 | AXX | BXO |
 |
 |
area: 0020 |
| S2756 | 2013.10.13 | S08E05 | plage | ||||||||
| 11871 | 2013.10.14 | 1 | N18E21 | 0020 | HSX |
 |
plage, SWPC has adopted the spots of AR S2753 | ||||
| 11872 | 2013.10.14 2013.10.15 |
1 | 3 | 2 | S17E41 | 0090 | HSX | HSX |
 |
 |
|
| 11873 | 2013.10.14 2013.10.16 |
10 | 15 | 9 | N11E48 | 0110 | CSO | DRO |
 |
 |
area: 0070 |
| S2759 | 2013.10.14 | S27W14 | plage | ||||||||
| S2760 | 2013.10.14 | S08W21 |
 |
plage | |||||||
| S2761 | 2013.10.15 | S09W64 |
 |
merged with AR 11761 | |||||||
| 11874 | 2013.10.16 2013.10.17 |
4 | 17 | 8 | S10E22 | 0020 | DAO | DAO |
 |
 |
|
| 11875 | 2013.10.16 2013.10.17 |
2 | 6 | 5 | N07E69 | 0050 | CAO | DSO |
 |
 |
area: 0150 location: N06E72 |
| S2764 | 2013.10.16 | 4 | 2 | N22W03 | 0009 | AXX |
 |
 |
|||
| S2767 | 2013.10.17 | 1 | S05E53 | 0001 | AXX |
 |
|||||
| Total spot count: | 46 | 108 | 58 | ||||||||
| Sunspot number: | 166 | 238 | 178 | (total spot count + 10 * number of spotted regions) | |||||||
| Weighted SN: | 63 | 142 | 92 | (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): | 100 | 83 | 98 | k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for STAR SDO 2K, k = 0.55 for STAR SDO 1K | |||||||
| 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 | 118.1 (1) | 55.3 (2A) / 100.9 (2B) / 57.6 (2C) | (53.9 projected, -1.5) | (10.78) |
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.
