Solar Terrestrial Activity Report

Last major update issued on June 15, 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 quiet to active on June 14. Solar wind speed ranged between 421 and 557 km/sec. A fairly weak solar wind shock was observed at ACE near 18:00 UTC when solar wind speed increased abruptly from 450 to 530 km/sec. The source of this shock was likely the faint full halo CME observed early on June 12. Another disturbance began after 01h UTC on June 15 when the high speed stream from CH170 was observed at ACE.

Solar flux measured at 20h UTC on 2.8 GHz was 93.8. The planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.3).
Three hour interval K indices: 22222243 (planetary), 22222233 (Boulder).

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

At midnight there were 4 spotted regions on the visible solar disk. The solar flare activity level was low. A total of 2 C class events was recorded during the day.

Region 10775 decayed further and has no spots outside of the single penumbra. Flares: C4.2/1F long duration event peaking at 07:30 (associated with a moderate type IV radio sweep and a full halo CME) and a C7.4 long duration event peaking at 15:48 UTC.
Region 10776 decayed further and was quiet.

Spotted regions not numbered by NOAA/SEC:
[S558] This region emerged in the northwest quadrant on June 14. Location at midnight: N10W36.
[S559] A new region emerged quickly on June 14 in the southeast quadrant. Location at midnight: S18E22.

Coronal mass ejections (CMEs)

June 14: A full halo CME was observed in LASCO images after a long duration C4 event in region 10775 during the morning. With no available LASCO images covering the C7 long duration event later in the day, it is uncertain if there was another full halo CME then.
June 13: No obvious fully or partly Earth directed CMEs were observed in LASCO images.
June 12: A faint full halo CME was observed after a very long duration C3.5 event in region 10775 early in the day.

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

An elongated coronal hole (CH170) in the northern hemisphere was in an Earth facing position on June 11-13.

Processed SOHO/EIT 284 image at 01:06 UTC on June 6. The darkest areas on the solar disk are likely coronal holes.


The geomagnetic field is expected to be unsettled to minor storm on June 15-16 due to a high speed stream from CH170. The CME observed on June 14 could arrive during the latter half of June 16 or early on June 17 and cause unsettled to major storm conditions.

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 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 and Radio Rafaela (Argentina). On other frequencies several stations from Brazil and Uruguay were heard. Rádio Metropolitana on 930 and Rádio Cristal on 1350 kHz both had impressive signals.

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
10775 2005.06.04 7 1 N09W59 0200 DAO classification was HAX at midnight
10776 2005.06.05 17 1 S06W48 0360 DKI classification was HHX at midnight
10777 2005.06.10     N05E02     plage
S556 2005.06.09     N05W60     plage
S558 2005.06.14   2 N10W36 0010 BXO  
S559 2005.06.14   4 S18E22 0070 DAO  
Total spot count: 24 8  
SSN: 44 48  

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)
2005.06 103.2 (1) 38.1 (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]