Last major update issued on August 15, 2010 at 02:50 UTC.
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The geomagnetic field was quiet on August 14. Solar wind speed ranged between 377 and 452 km/s.
Solar flux measured at 20h UTC on 2.8 GHz was 85.2. The planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.4). Three hour interval K indices: 10011112 (planetary), 10121012 (Boulder).
The background x-ray flux is at the class B1 level.
At midnight UTC the visible solar disk had 3 spotted regions.
Region 11093 decayed slowly.
Region 11097 was mostly unchanged and continues to display a few tiny spots.
Region 11099 has many fairly small spots and remains unstable. Further C flares are likely and an M class flare is possible. Flares: C4.4 long duration event peaking at 10:05 and C1.6 at 18:08 UTC. The C4.4 event was associated with a weak type II radio sweep, a CME (observed in STEREO-A where the fastest part of the ejected material was observed in a southeasterly direction) and an above 10 MeV proton event which crossed the event threshold of 1 pfu for a few minutes.
August 12-13: No obviously Earth directed CMEs were seen in LASCO or STEREO
August 14: A CME was observed after a C4.4 event in region 11099. The flank of this CME could influence Earth on August 17.
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 small, elongated, trans equatorial coronal hole (CH417) was Earth facing on August 11.
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 fair. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet to unsettled on August 15 due to weak effects from CH417. Quiet conditions are likely on August 16 and on August 17 until possible effects from a CME reach Earth. Should that happen a few unsettled and active intervals will be likely that day and early on August 18.
|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:||11||28|
|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)|
|2009.07||68.2||3.2||3.6 (+0.9)||5.49 / 4.55|
|2009.08||67.3||0.0||4.8 (+1.2)||5.70 / 4.89|
|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 predicted, +1.3)||4.15 / 4.61|
|2010.03||83.4||15.4||(12.3 predicted, +1.7)||4.58 / 4.65|
|2010.04||75.9||7.9||(13.9 predicted, +1.6)||10.22 / 10.24|
|2010.05||73.8||8.8||(15.3 predicted, +1.4)||9.18 / 8.15|
|2010.06||72.5||13.5||(16.7 predicted, +1.4)||8.17 / 6.85|
|2010.07||79.8||16.1||(18.3 predicted, +1.6)||6.31|
|2010.08||82.5 (1)||18.5 (2A) / 40.9 (2B)||(19.5 predicted, +1.2)||(9.73)|
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.