Solar Terrestrial Activity Report

Last major update issued on December 5, 2005 at 05:20 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-23 (last update November 9, 2005)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update November 9, 2005)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update November 9, 2005)]
[Historical solar and geomagnetic data charts 1954-2004 (last update February 1, 2005)]
[Archived reports (last update December 3, 2005)]

Recent activity

The geomagnetic field was inactive to quiet on December 4. Solar wind speed ranged between 507 and 689 (all day average 580) km/sec under the decreasing influence of a high speed stream from CH200.

Solar flux measured at 20h UTC on 2.8 GHz was 95.2. The planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 4.9)
Three hour interval K indices: 10012121 (planetary), 42133322 (Boulder).

The background x-ray flux is at the class B1 level.

At midnight there were 5 spotted regions on the visible solar disk. The solar flare activity level was low. A total of 1 C class event was recorded during the day.

Region 10826 decayed further and was mostly quiet. Flare: C2.1/1F long duration event peaking at 09:45 UTC.
Region 10828 decayed and lost about half of the penumbral coverage in the trailing spot section.
Region 10829 decayed further and is likely to become spotless today.
Region 10830 was quiet and stable.
New region 10831 emerged between regions 10826 and 10828.

Coronal mass ejections (CMEs)

December 3-4: No LASCO images available.
December 2: None of the major events in region 10826 produced other than possibly very small CMEs. The unavailability of LASCO images covering the hours after the M class event during the last hours of the day makes it difficult to confirm if there was any CME caused by this event.

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

No obvious coronal holes are currently in or near Earth facing positions.

Processed SOHO/EIT 284 image at 13:06 UTC on December 2. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet to unsettled on December 5-7.

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 fair. 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 Pompano Beach FL. A number of stations from the easternmost parts of the USA were noted with fair to good signals, one example is WAMG Dedham MA on 890 kHz with ESPN Boston programming.

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
10826 2005.11.28 25 26 S04W21 0380 EKC beta-gamma
classification was EKI at midnight
10827 2005.11.30     N08E03     plage
10828 2005.12.01 9 11 S04E04 0060 CSO location: S05E17
10829 2005.12.02 1 1 N10W26 0010 AXX  
10830 2005.12.02 3 1 N13E51 0100 CAO classification was HSX at midnight, area 0070
location: N12E49
10831 2005.12.04 3 12 S06W07 0030 DSO classification was DRI at midnight
S611 2005.12.02     S13W24     plage
Total spot count: 41 51  
SSN: 91 101  

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)
2004.10 105.9 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 31.6 (-1.9)
2005.05 99.3 42.6 28.9 (-2.7)
2005.06 93.7 39.6 (28.1 predicted, -0.8)
2005.07 96.4 39.9 (27.6 predicted, -0.5)
2005.08 90.5 36.4 (25.7 predicted, -1.8)
2005.09 91.1 22.1 (23.6 predicted, -2.1)
2005.10 77.0 8.5 (21.6 predicted, -2.0)
2005.11 86.3 18.0 (19.2 predicted, -2.4)
2005.12 100.3 (1) 11.0 (2) (16.4 predicted, -2.8)

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.


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