Solar Terrestrial Activity Report

Last major update issued on August 15, 2005 at 04:45 UTC.

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

Recent activity

The geomagnetic field was quiet to active on August 14. Solar wind speed ranged between 377 and 554 (all day average 461) km/sec, generally decreasing all day.

Solar flux measured at 20h UTC on 2.8 GHz was 74.8. The planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.5).
Three hour interval K indices: 44222222 (planetary), 34212222 (Boulder).

The background x-ray flux is at the class A4 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 10797 decayed in the leading spot section while slow development was observed in the trailing spots. C flares are possible.
New region 10798 rotated into view at the southeast limb on August 12 and was noticed by SEC two days later. Slow development was observed on August 14.

Coronal mass ejections (CMEs)

August 12-14: No obvious partly or fully 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

Recurrent trans equatorial coronal hole (CH181) was in an Earth facing position on August 13-15.

Processed SOHO/EIT 284 image at 01:06 UTC on August 15. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be quiet on August 15. A high speed stream from CH181 is likely to arrive on August 16 and cause unsettled to minor storm conditions until August 18.

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 to 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). Radio Cristal del Uruguay was audible at times. Stations from the easternmost parts of the US and Canada were audible on many frequencies throughout the MW band. The NY stations on 880, 1010, 1050, 1130, 1520 and 1560 had particularly good signals. CHGM good on 1150 with a couple of UNIDs observed on 1160 kHz. Cuba was noted on 620, 670, 840 and 890 kHz. 

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
10797 2005.08.11 13 23 S13E16 0180 DAI location: S14E14
10798 2005.08.14 1 2 S05E54 0010 HRX formerly region S582
location: S09E51
S578 2005.08.09     N05W82      
S580 2005.08.12     N27E02     first cycle 24 region
S581 2005.08.12     S10W01     plage
Total spot count: 14 25  
SSN: 34 45  

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)
2004.06 97.4 43.2 41.6 (-2.2)
2004.07 119.1 51.1 40.2 (-1.4)
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 (33.5 predicted, -1.1)
2005.03 89.9 24.5 (32.1 predicted, -1.4)
2005.04 86.0 24.4 (30.2 predicted, -1.9)
2005.05 99.3 42.6 (27.6 predicted, -2.6)
2005.06 93.7 39.6 (26.1 predicted, -1.5)
2005.07 96.4 39.9 (25.1 predicted, -1.0)
2005.08 90.6 (1) 28.6 (2) (23.2 predicted, -1.9)

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]