Last major update issued on October 5, 2006 at 02:25 UTC.
The next update will not be posted until October 14 or 15 when I have returned from the KONG14 DXpedition (see http://www.kongsfjord.no or http://arcticdx.blogspot.com/index.html)
geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update October 2, 2006)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update October 2, 2006)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update October 2, 2006)]
[Historical solar and geomagnetic data charts 1954-2005 (last update March 3, 2006)]
[Archived reports (last update October 2, 2006)]
The geomagnetic field was quiet on October 4. Solar wind speed ranged between 336 and 367 km/s (all day average 354 km/s - decreasing 25 km/s from the previous day).
Solar flux measured at 20h UTC on 2.8 GHz was 76.7. The planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 2.9). Three hour interval K indices: 12100111 (planetary), 02111211 (Boulder).
The background x-ray flux is at the class A1 level.
At midnight there were 2 spotted regions on the visible solar disk. The solar flare activity level was very low. No C class events were recorded during the day.
Region 10913 was quiet and stable.
Region 10914 was quiet and stable.
October 2-4: No obvious partly or fully Earth directed CMEs were detected in LASCO imagery.
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 coronal hole (CH242) in the northern hemisphere was in an Earth facing position on October 4.
Processed SOHO/EIT 284 image at 19:06 UTC on October 4. The darkest areas on the solar disk are likely coronal holes.
The geomagnetic field is expected to be mostly quiet on October 5-7 and 9-13. Late on October 7 and on October 8 effects from CH242 could cause some unsettled intervals. A recurrent coronal hole is likely to cause a disturbance October 14-16.
|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.
Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is fair to good. Propagation on long distance northeast-southwest paths is poor.
Lots of stations from the easternmost parts of North America were heard during the night. Some had excellent signals. CFDR on 780 kHz was like a local station at times. Some stations further south like 790 WAXY and 1290 WJNO had good signals as well with a few strong signals noted from the common Cuban and Colombian stations.
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|
|10914||2006.09.28||1||1||S09W04||0010||HRX||classification was HSX at midnight,
|Total spot count:||3||3|
flux at Earth
|International sunspot number||Smoothed sunspot number|
cycle 23 sunspot max.
|2006.04||89.0||30.2||(17.1 predicted, -0.2)|
|2006.05||80.9||22.2||(16.8 predicted, -0.3)|
|2006.06||76.5||13.9||(15.1 predicted, -1.7)|
|2006.07||75.7||12.2||(13.2 predicted, -1.9)|
|2006.08||79.0||12.9||(12.8 predicted, -0.4)|
|2006.09||77.8||14.5||(12.6 predicted, -0.2)|
|2006.10||77.4 (1)||3.8 (2)||(11.6 predicted, -1.0)|
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% lower.
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.