Solar Terrestrial Activity Report

Last major update issued on June 20, 2005 at 04:05 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 4, 2005)]

Recent activity

The geomagnetic field was very quiet to quiet on June 19. Solar wind speed ranged between 382 and 475 km/sec.

Solar flux measured at 20h UTC on 2.8 GHz was 86.9. The planetary A index was 7 (STAR Ap - based on the mean of three hour interval ap indices: 6.6).
Three hour interval K indices: 21222222 (planetary), 11222221 (Boulder).

The background x-ray flux is at the class A7 level.

At midnight there were 2 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 10779 decayed slowly losing spots and penumbral area. Flare: C2.1 at 19:25 UTC.
Region 10780 did not change significantly although some spots disappeared while others emerged.

Coronal mass ejections (CMEs)

June 17-19: No obvious fully or partly Earth directed CMEs were observed in available LASCO images.

An almost continuous stream of ejected material was observed from a source behind the east limb on June 18-19.

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 01:06 UTC on June 6. The darkest areas on the solar disk are likely coronal holes.

Forecast

The geomagnetic field is expected to be mostly quiet on June 20-22.

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 poor to very poor. Propagation along long distance north-south paths is fair. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: Radio Cristal del Uruguay. Many stations from Brazil, Argentina and Uruguay were noted on other frequencies, Radio Rincón on 1510 kHz had a good signal although there was at times heavy interference form other stations on the same frequency.

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
10777 2005.06.10     N05W63     plage
10778 2005.06.15     N08W89     plage
10779 2005.06.15 16 22 S17W45 0460 EKO  
10780 2005.06.17 7 7 S07E38 0040 DSO  
S560 2005.06.16     N08W02     plage
Total spot count: 23 29  
SSN: 43 49  

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)
2005.06 100.3 (1) 47.5 (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]