Last major update issued on February 11, 2011 at 04:30 UTC.
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Annotated geomagnetic activity charts - Carrington rotation 2104 [Nov-Dec.2010]- 2105 [Dec-Jan.2011] NEW
The geomagnetic field was quiet on February 10. Solar wind speed ranged between 339 and 393 km/s under the influence of a weak coronal hole stream.
Solar flux measured at 20h UTC on 2.8 GHz was 91.4 (increasing 12.1 over the last solar rotation). The planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.0). Three hour interval K indices: 00211001 (planetary), 01321111 (Boulder).
The background x-ray flux is at the class B2 level.
At midnight UTC the visible solar disk had 5 spotted regions.
(Region 11153 continued to produce flares from behind the northwest limb.
There is still a slight chance of an M class event. Flares:
C1.9 at 06:40, C2.0 at 06:58, C4.7 at 12:34 and C2.6 at 13:52 UTC.)
Region 11156 developed slowly and has rudimentary penumbra on both polarities with many intermediate spots.
Region 11157 decayed and was quiet.
Spotted regions not numbered by NOAA/SWPC:
[S873] This region emerged in the southeast quadrant on February 10 and is developing moderately quickly early on February 11. Location at midnight: S19E38
[S874] A new region emerged in the northeast quadrant on February 10. Location at midnight: N20E42
[S875] This region emerged in the northeast quadrant to the east of region S874. Location at midnight: N21E54
February 8-10: 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 significant coronal holes are currently in or near Earth facing positions.
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 poor to fair. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet on February 11-13.
|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.
(Click on image for higher resolution image) Compare to the previous day's image
When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue (blue-green) 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 polarity overlay
|N17E00||2 threshold spots observed|
|Total spot count:||18||32|
|Month||Average measured solar flux||International sunspot number (SIDC)||Smoothed sunspot number||Average ap
|2008.07||65.7 (SF minimum)||0.5||2.8 (-0.4)|
|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||16.4 (+0.9)||8.17 / 6.85|
|2010.07||79.8||16.1||16.8 (+0.4)||6.31 / 5.15|
|2010.08||79.2||19.6||(17.1 predicted, +0.3)||8.49 / 7.77|
|2010.09||81.1||25.2||(17.7 predicted, +0.6)||5.33 / 5.45|
|2010.10||81.6||23.5||(19.0 predicted, +1.3)||6.07 / 6.27|
|2010.11||82.5||21.6||(20.7 predicted, +1.7)||4.80 / 5.50|
|2010.12||84.2||14.5||(22.2 predicted, +1.5)||3.41 / 4.35|
|2011.01||83.6||19.1||(23.8 predicted, +1.6)||4.32|
|2011.02||83.5 (1)||13.5 (2A) / 37.9 (2B)||(25.5 predicted, +1.7)||(7.40)|
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) Month average to date.
3) Running average based on the preliminary 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.