Solar Terrestrial Activity Report

Last major update issued on July 1, 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 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 to unsettled on June 30. Solar wind speed ranged between 354 and 427 (all day average 377) km/sec.

Solar flux measured at 20h UTC on 2.8 GHz was 102.5. The planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 7.5).
Three hour interval K indices: 11122323 (planetary), 21223333 (Boulder).

The background x-ray flux is at the class B2 level.

At midnight there were 6 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 stable.
Region 10782 developed further and could produce C flares.
Region 10783 increased its penumbral coverage, however, the region appears magnetically somewhat simpler than a day ago.
Region 10784 decayed slowly and quietly.
New region 10785 emerged in the southeast quadrant on June 29 and was numbered by NOAA/SEC the next day.

Spotted regions not numbered by NOAA/SEC:
[S565] This region emerged to the north of region 10782 on June 30. The region appeared to be decaying during the last hours of the day. Location at midnight: S09W09.

Coronal mass ejections (CMEs)

June 28-30: 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 July 1. The darkest areas on the solar disk are likely coronal holes.

Forecast

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 during the latter half of 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.

Propagation

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 poor to very poor. Trans Atlantic propagation conditions are normally monitored every night on 1470 kHz. Dominant station tonight: Radio Vibración (Venezuela). Radio Cristal del Uruguay was heard occasionally. From North America the only stations noted were CJYQ on 930 and WWZN on 1510 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
10781 2005.06.27 4 2 N14E37 0050 HRX classification was CSO at midnight
10782 2005.06.29 17 19 S17W04 0090 DAI area was 0160 at midnight, location: S17W06
10783 2005.06.29 16 13 S02E46 0170 DSO classification was DAO at midnight
10784 2005.06.29 6 4 N16E57 0070 DSO  
10785 2005.06.30 3 9 S18E21 0020 CAO formerly region S564
S563 2005.06.27     N10W04     plage
S565 2005.06.30   2 S09W09 0010 BXO  
Total spot count: 46 49  
SSN: 96 109  

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 93.7 (1) 59.8 (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]