Last major update issued on March 8, 2010 at 03:50 UTC.
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The geomagnetic field was quiet tu unsettled on March 7. Solar wind speed ranged between 346 and 424 km/s, early in the day under the influence of a coronal hole related disturbance.
Solar flux measured at 20h UTC on 2.8 GHz was 76.6. The planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.3). Three hour interval K indices: 23200001 (planetary), 22300000 (Boulder).
The background x-ray flux is at the class A2 level.
At midnight there was 1 spotted region on the visible solar disk.
Spotted regions not numbered by NOAA/SWPC:
[S755] The region emerged in the northeast quadrant on March 6 and developed slowly on March 7.
March 5 and 7: No obvious Earth directed CMEs were observed in LASCO
March 6: A filament eruption near S755 at 05:30 UTC was the origin of a CME observed off of most of the east limb. There's a possibility that the outer edges of the CME could reach Earth on March 9 and cause a minor disturbance.
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, poorly defined trans equatorial coronal hole (CH395) rotated across the central meridian on March 7.
Processed SOHO/EIT 195 image at 23:48 UTC on March 7. 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 on March 8 and quiet to unsettled on March 9-10.
|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||SWPC
|Location at midnight||Area||SWPC
|Total spot count:||0||2|
|Month||Average measured solar flux||International sunspot number (SIDC)||Smoothed sunspot number||Average ap
cycle 23 sunspot max.
|2009.07||68.2||3.5||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||4.2||(6.4 predicted, +1.6)||3.88 / 3.61|
|2009.10||72.6||4.6||(8.3 predicted, +1.9)||3.66 / 3.56|
|2009.11||73.6||4.2||(10.3 predicted, +2.0)||2.45 / 2.63|
|2009.12||76.7||10.6||(12.4 predicted, +2.1)||1.41 / 1.92|
|2010.01||81.1||13.1||(15.0 predicted, +2.6)||2.93 / 3.07|
|2010.02||84.7||18.6||(17.9 predicted, +2.9)||4.15|
|2010.03||79.3 (1)||6.1 (2)||(21.1 predicted, +3.2)||(4.5)|
1) Running average based on the
daily 20:00 UTC observed solar flux
value at 2800 MHz.
2) Unofficial, accumulated value based on the Boulder (NOAA/SWPC) sunspot number. The official international sunspot number is typically 30-50% lower.
3) Running average based on the daily SWPC ap indices. Values in red are based on official NGDC ap indices.
This report has been prepared by Jan Alvestad. It is based partly on my own observations and analysis, and partly on data from some of these solar data sources. All time references are to the UTC day. Comments and suggestions are always welcome.