Last major update issued on October 16, 2013 at 06:15 UTC.
[Solar and geomagnetic data - last month (updated
[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 active on October 15. Solar wind speed at SOHO ranged between 462 and 577 km/s under the influence of a high speed stream from CH590.
Solar flux measured at 20h UTC on 2.8 GHz was 125.3 (increasing 21.2 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 112.4. The Potsdam WDC planetary A index was 17 (STAR Ap - based on the mean of three hour interval ap indices: 16.8). Three hour interval K indices: 44342113 (planetary), 33433213 (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 12 active regions in 2K resolution (SN: 218) and 10 active regions in 1K resolution (SN: 152) SDO images on the visible solar disk.
Region 11861 [S08W45] developed and became a
compact region again with the trailing large penumbra becoming asymmetrical. The
chance of an M class flare has increased.
Region 11863 [S19W78] decayed slowly and quietly.
Region 11864 [S22W27] decayed slowly with a decrease in penumbral area. Further M class flares are possible as there is still a magnetic delta structure. C5+ flares: C9.5 at 05:07, M1.8 at 08:38, C6.5 at 15:36, M1.3 at 23:36 UTC.
Region 11867 [N23W59] decayed slowly and quietly.
Region 11869 [N18E38] was mostly unchanged and quiet.
Region 11870 [S14W21] decayed slowly and quietly.
Region 11871 [N17E52] decayed slowly and quietly.
New region 11872 [S18E68] rotated into view on Oct.14 and was numbered the next day by SWPC.
Spotted regions not numbered by SWPC:
S2745 [N05W34] was quiet and stable.
S2753 [N18E46] developed slowly and quietly.
S2758 [N11E75] was quiet and developed slowly.
New region S2761 [S09W36] emerged to the east of AR 11861
October 14-15: No obviously Earth directed CMEs were observed in LASCO and
October 13: A partial halo CME was observed after an M1 flare in AR 11864 early in the day. There is a 20-30% chance the CME could reach Earth late on October 15 or on October 16.
Coronal hole history (since October
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago
A recurrent trans equatorial coronal hole (CH590) was in an Earth facing position on October 11-12. A recurrent coronal hole (CH591) in the northern hemisphere will rotate 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. Propagation on long distance northeast-southwest paths is fair to good.
The geomagnetic field is expected to be quiet to active on October 16 due to effects from CH590. Quiet conditions are likely on October 17-18.
|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
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
|Spot count||Location at midnight||Area||Classification||SDO / HMI 4K continuum
image with magnetic polarity overlay
|11865||2013.10.08||11||S21W21||0090||DAO||part of AR 11864|
|Total spot count:||48||98||52|
|Sunspot number:||148||218||152||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||88||140||94||(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):||89||76||84||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
|2011.11||153.5 (cycle peak)||96.7 (cycle peak)||61.1 (+1.2)||5.55|
likely cycle 24 max
|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||116.2 (1)||46.1 (2A) / 95.3 (2B) / 54.3 (2C)||(53.9 projected, -1.5)||(11.08)|
1) Running average based on the daily 20:00 UTC observed solar flux value at
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.