Last major update issued on December 9, 2004 at 04:55 UTC.
[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update December 3, 2004)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update December 3, 2004)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update December 3, 2004)]
[Historical solar and geomagnetic data charts 1954-2004 (last update November 8, 2004)]
[Archived reports (last update December 1, 2004)]
The geomagnetic field was quiet to unsettled on December 8. Solar wind speed ranged between 413 and 511 km/sec under the influence of a coronal hole flow.
Solar flux measured at 18h UTC on 2.8 GHz was 80.9 (the measurement at 20h UTC was enhanced because of a long duration event). The planetary A
index was 10 (STAR Ap - based on themean of three hour interval ap indices: 9.6).
Three hour interval K indices: 32322232 (planetary), 32422232 (Boulder).
The background x-ray flux is at the class A8 level.
At midnight there were 3 spotted regions on the visible solar disk. The solar flare activity level was low. A total of 2 C class events was recorded during the day.Region 10708 was quiet and stable and is rotating over the northwest limb.
December 8: With only a few LASCO images available for the time after the LDE in region 10709, it is hard to tell how large
and fast the associated CME was. Still it is likely that a CME will reach Earth on December 11 and cause unsettled to minor storm
December 6-7: No obviously Earth directed CMEs observed.
Coronal hole history (since late October 2002)
Compare today's report with the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago
A small coronal hole in the southern hemisphere could rotate into a geoeffective position on December 9-10.
Processed SOHO/EIT 284 image at 19:06 UTC on December 8. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on December 9, quiet on December 10 and quiet to minor storm on December 11-12
|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) Material from a CME is likely to impact 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.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is poor. Propagation along long distance north-south paths is fair. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay and Radio Vibración. On other frequencies propagation was best towards Brazil before 02h UTC and best towards the easternmost part of North America after 04h UTC.
Compare to the previous day's image.
Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SEC. 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 SEC or where SEC has observed no spots. SEC active region numbers in the table below and in the active region map above are the historic SEC/USAF numbers.
|Active region||Date numbered||SEC
|Location at midnight||Area||Classification||Comment|
classification was HSX
classification was AXX
at midnight, area 0000
areas was 0010
|Total spot count:||10||6|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2004.06||97.4||43.2||(42.2 predicted, -1.7)|
|2004.07||119.1||51.0||(40.6 predicted, -1.6)|
|2004.08||109.6||40.9||(39.0 predicted, -1.6)|
|2004.09||103.1||27.7||(37.1 predicted, -1.9)|
|2004.10||105.9||48.4||(34.9 predicted, -2.2)|
|2004.11||113.2||43.7||(33.0 predicted, -1.9)|
|2004.12||96.8 (1)||12.3 (2)||(30.7 predicted, -2.3)|
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/SEC) sunspot number. The official international sunspot number is typically 30-50% less.
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.