Solar Terrestrial Activity Report

Last major update issued on June 30, 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 June 4, 2005)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update June 4, 2005)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update June 4, 2005)]
[Historical solar and geomagnetic data charts 1954-2004 (last update February 1, 2005)]
[Archived reports (last update June 21, 2005)]

Recent activity

The geomagnetic field was quiet on June 29. Solar wind speed ranged between 352 and 434 (all day average 384) km/sec.

Solar flux measured at 20h UTC on 2.8 GHz was 88.9. The planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 5.9).
Three hour interval K indices: 21122222 (planetary), 22221311 (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 very low. No C class events were recorded during the day.

Region 10781 was quiet and didn't change significantly.
New region 10782 emerged quickly in the southeast quadrant. C flares are possible.
New region 10783 emerged quickly near the southeast limb and is currently the most interesting of the visible regions. The region is compact and has some polarity intermixing. C flares are possible. Should the current rate of development be sustained for another day we will likely see M class flares.
New region 10784 rotated into view at the northeast limb and developed slowly. C flares are possible.

Spotted regions not numbered by NOAA/SEC:
[S564] This region emerged on June 29 in the southeast quadrant. Location at midnight: S17E33.

Coronal mass ejections (CMEs)

June 27-29: No obvious fully or partly Earth directed CMEs were observed in available LASCO images.

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 large trans equatorial coronal hole (CH173) was in an Earth facing position on June 28-30.

Processed SOHO/EIT 284 image at 01:06 UTC on June 30. The darkest areas on the solar disk are likely coronal holes.


The geomagnetic field is expected to be quiet on June 30. A high speed stream from CH173 will likely arrive on July 1 and cause unsettled to major storm conditions that day and on July 2. Quiet to active is possible on July 3-4. 

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.


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 good. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant stations tonight: Radio Cristal del Uruguay and Radio Vibración (Venezuela). Many stations were heard on other frequencies with the main focus on Argentina (910, 1030, 1070 and 1190 kHz had the best signals). CJYQ on 930 kHz was the only North American station, however, they did have a nice signal for a couple of hours until Radio Monte Carlo reclaimed the spot as the dominant station on the frequency. CJYQ was only noted on a new antenna directed westwards.

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
Location at midnight Area Classification Comment
10781 2005.06.27 5 5 N15E53 0080 CAO classification was CSO at midnight, area 0060
10782 2005.06.29 3 16 S17E09 0010 BXO classification was DAI at midnight, area 0080, location: S16E08
10783 2005.06.29 4 10 S01E59 0040 CSO beta-gamma
classification was DAC at midnight, area 0090, location: S02E58
10784 2005.06.29 5 7 N16E70 0050 BXO beta-gamma
classification was DAO at midnight, area 0040, location: N16E68
S562 2005.06.27     S15W45     plage
S563 2005.06.27     N10E09     plage
S564 2005.06.29   2 S16E33 0010 BXO  
Total spot count: 17 40  
SSN: 57 90  

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)
2004.04 101.2 39.3 45.5 (-1.6)
2004.05 99.8 41.5 43.8 (-1.7)
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 (34.8 predicted, -0.5)
2005.01 102.2 31.3 (32.8 predicted, -2.0)
2005.02 97.2 29.1 (30.4 predicted, -2.4)
2005.03 89.9 24.8 (28.8 predicted, -1.6)
2005.04 86.0 24.4 (26.9 predicted, -1.9)
2005.05 99.3 42.6 (24.3 predicted, -2.6)
2005.06 93.4 (1) 56.6 (2) (22.8 predicted, -1.5)

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]