Solar Terrestrial Activity Report

Last major update issued on October 31, 2005 at 04:10 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, 2005)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update October 2, 2005)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update October 2, 2005)]
[Historical solar and geomagnetic data charts 1954-2004 (last update February 1, 2005)]
[Archived reports (last update October 2, 2005)]

Recent activity

The geomagnetic field was quiet on October 30. Solar wind speed ranged between 314 and 357 (all day average 334) km/sec.

Solar flux measured at 20h UTC on 2.8 GHz was 75.6. The planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 4.8).
Three hour interval K indices: 22001012 (planetary), 21012311 (Boulder).

The background x-ray flux is at the class A2 level.

At midnight there was 1 spotted region on the visible solar disk. The solar flare activity level was very low. No C class events were recorded during the day.

Coronal mass ejections (CMEs)

October 28-30: No obvious fully or partly Earth directed CMEs were observed.

Coronal holes

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 recurrent trans equatorial coronal hole (CH195) will likely rotate into an Earth facing position on November 1-3.

Processed SOHO/EIT 284 image at 01:06 UTC on October 31. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to unsettled on October 31 - November 3 becoming quiet to active on November 4-6 due to effects from CH195.

Coronal holes (1) Coronal mass ejections (2) M and X class flares (3)
Coronal hole indicator CME indicator M and X class flare indicator

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.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along east-west paths over high and upper middle latitudes is very good. Propagation on long distance northeast-southwest paths is poor. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant stations tonight: Radio Vibración (Venezuela) and WWNN Boca Raton FL. Propagation was excellent to some parts of the US east coast and to Puerto Rico. WQBA Miami 1140 had a stunning signal for some time. On 1490 kHz WBAE Portland and WMBM Miami Beach alternated as the dominant signal. WEUV Huntsville AL on 1700 kHz was the best I've heard them.

Active solar regions (Recent map)

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
spot
count
STAR
spot
count
Location at midnight Area Classification Comment
10817 2005.10.23     N04W70     plage
10818 2005.10.29 4 6 S06E47 0040 CSO classification was DSO at midnight, area 0050
S599 2005.10.22     S08W67     plage
Total spot count: 4 6  
SSN: 14 16  

Monthly solar cycle data

Month Average solar
flux at Earth
International sunspot number Smoothed sunspot number
2000.04 184.2 125.5 120.8
cycle 23 sunspot max.
2000.07 202.3 170.1 119.8
2001.12 235.1 132.2 114.6 (-0.9)
2004.08 109.6 40.9 39.2 (-1.0)
2004.09 103.1 27.7 37.5 (-1.7)
2004.10 105.9 48.0 35.9 (-1.6)
2004.11 113.2 43.5 35.3 (-0.6)
2004.12 94.5 17.9 35.2 (-0.1)
2005.01 102.2 31.3 34.6 (-0.6)
2005.02 97.2 29.2 33.9 (-0.7)
2005.03 89.9 24.5 33.5 (-0.4)
2005.04 86.0 24.4 (31.9 predicted, -1.6)
2005.05 99.3 42.6 (29.4 predicted, -2.5)
2005.06 93.7 39.6 (28.1 predicted, -1.3)
2005.07 96.4 39.9 (26.9 predicted, -1.2)
2005.08 90.5 36.4 (25.0 predicted, -1.9)
2005.09 91.1 22.1 (23.0 predicted, -2.0)
2005.10 77.0 (1) 12.0 (2) (21.0 predicted, -2.0)

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.


[DX-Listeners' Club]