Last major update issued on October 3, 2004 at 02:55 UTC.
[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update October 2, 2004)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update October 2, 2004)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update October 2, 2004)]
[Historical solar and geomagnetic data charts 1954-2004 (last update August 28, 2004)]
[Archived reports (last update September 27, 2004)]
The geomagnetic field was quiet to active on October 2. Solar wind speed ranged between 301 and 386 km/sec under the influence of a low speed stream from coronal hole CH116.
Solar flux measured at 20h UTC on 2.8 GHz was 88.0. The planetary A
index was 12 (STAR Ap - based on the mean of three hour interval ap indices: 13.5).
Three hour interval K indices: 23334322 (planetary), 22333222 (Boulder).
The background x-ray flux is at the class A4 level.
At midnight there were 2 spotted regions on the visible disk. The solar flare activity level was very low. No C class events were recorded during the day.
Region 10675 developed a couple of small trailing spots to the southeast of the single penumbra.
Region 10676 decayed slowly and quietly.
September 30 - October 2: 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 poorly defined trans equatorial coronal hole (CH117) will rotate into a geoeffective position on October 3-4.
Processed SOHO/EIT 284 image at 19:06 UTC on September 10. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be quiet to unsettled on October 3 and quiet on October 4-5. On October 6-7 a coronal hole flow could cause unsettled to active conditions.
|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 poor to fair. Trans Atlantic propagation conditions are monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay and Radio Vibración (Venezuela). A couple of unidentified Brazilians were heard early (00:45 UTC) in the listening session). On other frequencies a few stations from the Caribbean (Radio Visión Cristiana on 530, Harbour Light on 1400, WDHP on 1620 and Radio Juventus don Bosco on 1640 kHz) were present. From North America only a few signals could be heard. Newfoundland stations were on 590, 620, 750, 800 and 930 kHz (CJYQ with the best signal of all trans Atlantic stations) with the only US station being WWZN on 1510 kHz.
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 CSO
|10677||2004.09.28||2||N02W21||0010||AXX||spotless all day|
|Total spot count:||5||5|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2004.04||101.2||39.3||(44.6 predicted, -2.5)|
|2004.05||99.8||41.5||(40.9 predicted, -3.7)|
|2004.06||97.4||43.2||(38.0 predicted, -2.9)|
|2004.07||119.1||51.0||(36.2 predicted, -1.8)|
|2004.08||109.6||40.9||(34.6 predicted, -1.6)|
|2004.09||103.1||27.7||(32.8 predicted, -1.6)|
|2004.10||88.0 (1)||2.3 (2)||(30.5 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.