Last major update issued on December 10, 2013 at 05:55 UTC.
[Solar and geomagnetic data - last month (updated
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update December 1, 2013)] [Cycle 24 progress (last update December 1, 2013) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update December 1, 2013)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update December 1, 2013)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update December 1, 2013)]
[POES auroral activity level since October
2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated December 3, 2013]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]
The geomagnetic field was quiet on December 9. Solar wind speed at SOHO ranged between 377 and 610 km/s under the weakening influence of a CME related disturbance.
Solar flux measured at 20h UTC on 2.8 GHz was 168.1 (increasing 0.6 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 131.0. The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.3). Three hour interval K indices: 10001211 (planetary), 10012211 (Boulder).
The background x-ray flux was at the class C1 level.
At the time of counting spots (see image time) spots were observed in 13 active regions in 2K resolution (SN: 305) and 11 active regions in 1K resolution (SN: 190) SDO images on the visible solar disk.
Region 11912 [S20W25] was quiet and stable.
Region 11916 [S12W51] was mostly quiet and stable. The region has many spots but is currently not complex magnetically.
Region 11917 [S16E43] developed slowly and quietly.
Region 11918 [S09E64] was quiet and stable.
New region 11919 [S05W23] emerged on December 8 and was numbered the next day by SWPC.
New region 11920 [N08E76] rotated partly into view on December 8 and got its NOAA number the next day. The region has a very extensive trailing positive polarity field with hardly any spots. SWPC has numbered the southern spots as a region on its own. Currently the spots belong magnetically to one region.
Spotted regions not numbered by SWPC:
S2876 [S15W67] reemerged with a penumbra spot.
S2892 [S15E12] was quiet and stable and has many penumbra spots.
S2896 [N17E42] was quiet and stable.
S2897 [N16E13] was quiet and stable. The region has reversed polarities.
S2903 [N12W03] developed slowly and quietly.
S2906 [N10E50] decayed slowly and quietly.
New region S2907 [S12W33] emerged with a penumbra spot.
December 8-9: No obviously Earth directed CMEs were observed in LASCO
December 7: A CME was observed in STEREO imagery after an M1 event in AR 11909. The partial halo CME was wide and could have an Earth directed extension.
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 large northern hemisphere coronal hole (CH597) will likely rotate into an Earth facing position on December 11.
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 poor.
The geomagnetic field is expected to be quiet to unsettled on December 10 due to weak CME effects and quiet on December 11-13. A high speed stream from CH597 could cause unsettled and active intervals on December 14-15.
|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
|11921||2013.12.09||2||N06E75||0120||HSX||magnetically part of AR 11920|
|Total spot count:||45||175||80|
|Sunspot number:||125||305||190||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||83||217||122||(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):||75||107||105||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|
possibe cycle 24 max
|2013.06||110.1||52.5||(61.5 projected, +1.6)||12.60|
|2013.07||115.5||57.0||(62.1 projected, +0.6)||9.47|
|2013.08||114.6||66.0||(62.3 projected, +0.2)||8.27|
|2013.09||102.6||36.9||(61.2 projected, -1.1)||5.23|
|2013.10||132.1||85.6||(59.0 projected, -2.2)||7.71|
|2013.11||148.3||77.6||(57.3 projected, -1.7)||5.68|
|2013.12||147.5 (1)||30.4 (2A) / 104.8 (2B) / 80.6 (2C)||(56.1 projected, -1.2)||(6.7)|
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.