Last major update issued on January 7, 2011 at 04:55 UTC.
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[Annotated geomagnetic activity chart - Carrington rotation 2104 - NEW]
The geomagnetic field was quiet to minor storm on January 6. Solar wind speed ranged between 319 and 527 km/s. A high speed stream associated with CH431 arrived at SOHO around 20h UTC and caused a stronger than expected geomagnetic disturbance.
Solar flux measured at 20h UTC on 2.8 GHz was 86.8 (down 1.6 over the last solar rotation). The planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.0). Three hour interval K indices: 11000115(planetary), 21000214(Boulder).
The background x-ray flux is at the class A7 level.
At midnight UTC the visible solar disk had 4 spotted regions.
Region 11139 reemerged with a couple of tiny spots.
Region 11140 was mostly unchanged and quiet.
Region 11142 decayed further and could soon become spotless.
Spotted regions not numbered by NOAA/SWPC:
[S859] This region emerged in the southeast quadrant on January 5 did not change significantly on January 6. Location at midnight: S23E33
January 4-6: 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
A coronal hole (CH431) in the northern hemisphere was in an Earth facing position on January 3-4. A recurrent trans equatorial coronal hole (CH432) was Earth facing on January 4-5. A recurrent coronal hole (CH433) in the northern hemisphere will likely rotate into an Earth facing position on January 9-11.
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. Propagation on long distance northeast-southwest paths is poor to fair.
The geomagnetic field is expected to be quiet to active on January 7-9 due to effects from CH431 and CH432. Mostly quiet conditions are likely on January 10-11.
|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
|Total spot count:||8||14|
|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)|
|2009.10||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||16.4 (+0.9)||8.17 / 6.85|
|2010.07||79.8||16.1||(17.0 predicted, +0.6)||6.31 / 5.15|
|2010.08||79.2||19.6||(17.9 predicted, +0.9)||8.49 / 7.77|
|2010.09||81.1||25.2||(19.0 predicted, +1.1)||5.33 / 5.45|
|2010.10||81.6||23.5||(20.7 predicted, +1.7)||6.07 / 6.27|
|2010.11||82.5||21.6||(23.0 predicted, +2.3)||4.80|
|2010.12||84.2||14.5||(25.3 predicted, +2.3)||3.41|
|2011.01||89.9 (1)||9.2 (2A) / 47.7 (2B)||(27.7 predicted, +2.4)||(3.98)|
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.