Last major update issued on December 28, 2010 at 05:00 UTC. Minor update posted at 15:45 UTC.
[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-24 (last update December 3, 2010)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update December 3, 2010)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update December 3, 2010)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports from January 2003 (last update December 3, 2010)]
[POES auroral activity level
charts since October 2009]
[Geomagnetic activity chart - Carrington rotation 2104 - NEW]
The geomagnetic field was very quiet on December 27. Solar wind speed ranged between 282 and 410 km/s.
Solar flux measured at 20h UTC on 2.8 GHz was 80.1 (down 6.3 over the last solar rotation). The planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 1.8). Three hour interval K indices: 10000001 (planetary), 10000211 (Boulder).
The background x-ray flux is at the class A4 level.
At midnight UTC the visible solar disk had 2 spotted regions.
Region 11137 was quiet and displayed no significant changes.
New region 11138 emerged on December 26 in the northeast quadrant and was numbered the next day by NOAA/SWPC. The region developed slowly on December 27.
Minor update posted at 15:45 UTC: Geomagnetic activity increased strongly after 10h UTC in response to the arrival of what was likely a CME observed on December 23. The planetary A index reached 48 for the 12-15 UTC interval.
December 25-27: No obviously Earth directed CMEs were observed in LASCO or STEREO images.
Coronal hole history (since late October 2002)
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago
No obvious coronal holes are currently in or near Earth facing positions.
Image courtesy of SDO (NASA) and the AIA consortium. Annotations are my own. The darkest areas on the solar disk are likely coronal holes.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is good. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet on December 28-31.
|Coronal holes (1)||Coronal mass ejections (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.
Compare to the previous day's image
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 (NASA) / AIA 4500
|11137||2010.12.25||2||N18W03||0000||BXO||due to SDO/AIA data lag the base image source is SOHO/MDI continuum|
|11138||2010.12.26||4||9||N13W12||0050||DAO||DAO||formerly region S853
the base image source is SOHO/MDI continuum
|Total spot count:||4||11|
|Month||Average measured solar flux||International sunspot number (SIDC)||Smoothed sunspot number||Average ap
cycle 23 sunspot max.
|2008.07||65.7 (SF minimum)||0.5||2.8 (-0.4)|
|2009.09||70.5||4.3||6.2 (+1.4)||3.88 / 3.61|
|2009.10||72.6||4.8||7.1 (+0.9)||3.66 / 3.56|
|2009.11||73.6||4.1||7.6 (+0.5)||2.45 / 2.63|
|2009.12||76.7||10.8||8.3 (+0.7)||1.41 / 1.92|
|2010.01||81.1||13.2||9.3 (+1.0)||2.93 / 3.07|
|2010.02||84.7||18.8||10.6 (+1.3)||4.15 / 4.61|
|2010.03||83.4||15.4||12.3 (+1.7)||4.58 / 4.65|
|2010.04||75.9||8.0||14.0 (+1.7)||10.22 / 10.24|
|2010.05||73.8||8.7||15.5 (+1.5)||9.18 / 8.15|
|2010.06||72.5||13.6||(16.9 predicted, +1.4)||8.17 / 6.85|
|2010.07||79.8||16.1||(18.4 predicted, +1.5)||6.31 / 5.15|
|2010.08||79.2||19.6||(19.6 predicted, +1.2)||8.49 / 7.77|
|2010.09||81.1||25.2||(20.8 predicted, +1.2)||5.33 / 5.45|
|2010.10||81.6||23.5||(23.2 predicted, +2.4)||6.07 / 6.27|
|2010.11||82.5||21.6||(26.1 predicted, +2.9)||4.80|
|2010.12||84.2 (1)||18.3 (2A) / 21.0 (2B)||(28.6 predicted, +2.5)||(2.99)|
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 international sunspot number is typically 30-50% lower. 2B) Month average to date.
3) Running average based on the daily SWPC ap indices. Values in red are based on the official NGDC ap indices.
This report has been prepared by Jan Alvestad. It is based on 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.