Solar Terrestrial Activity Report

Last major update issued on June 12, 2010 at 04:45 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-24 (last update May 26, 2010)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22 and 23 (last update October 4, 2007)]
[Graphical comparison of cycles 2, 10, 13, 17, 20 and 23 (last update October 4, 2007)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports (last update April 2, 2010)]

Recent activity

The geomagnetic field was quiet on June 11. Solar wind speed ranged between 348 and 449 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 74.6. The planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 4.9). Three hour interval K indices: 22111111 (planetary), 22112112 (Boulder).

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

At midnight there were 2 spotted regions on the visible solar disk.

Region 11080 was quiet and stable.
New region 11081 emerged quickly in the northwest quadrant. The region has polarity intermixing, and a magnetic delta structure could be forming in the leading spot section. An M2.0 flare (with an associated moderately strong type II radio sweep) was recorded at 00:57 UTC on June 12. Further M class flares are possible.

Coronal mass ejections (CMEs)

June 9-11: No obvious Earth directed CMEs were observed in LASCO or STEREO images.
June 12: A CME was observed in STEREO-A images after the M2 flare in region 11081. Too few images are currently available to forecast whether or not this CME could have any influence on the geomagnetic field.

Coronal holes

Coronal hole history (since late October 2002)
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago

A recurrent trans equatorial coronal hole (CH408) will rotate into an Earth facing position on June 12-13.

Processed SOHO/EIT 195 image at 00:00 UTC on June 12. The darkest areas on the solar disk are likely coronal holes.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is poor to fair. Propagation on long distance northeast-southwest paths is poor to fair.

Forecast

The geomagnetic field is expected to be quiet on June 12-14 becoming quiet to active on June 15-16 due to effects from CH408. Should the CME observed early on June 12 have any Earth directed components, it could influence the geomagnetic field on June 15.

Coronal holes (1) Coronal mass ejections (2) M and X class flares (3)



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) Effects from a CME are likely to be observed at 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.

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/SWPC. 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 SWPC or where SWPC has observed no spots. SWPC active region numbers in the table below and in the active region map above are the historic SWPC/USAF numbers.

Active region Date numbered SWPC
spot
count
STAR
spot
count
Location at midnight Area SWPC
Classification
Comment
11078 2010.06.08 1   S22W86 0005 AXX rotated out of view
11079 2010.06.09     S26W68     plage
11080 2010.06.09 4 7 S23W54 0100 DAI classification was DSO at midnight, area 0050
S778 2010.06.10     N19W71     plage
11081 2010.06.11 8 18 N22W43 0050 BXO classification was DAI at midnight, area 0080
beta-gamma
Total spot count: 13 25  
SSN: 43 45  

Monthly solar cycle data

Month Average measured solar flux International sunspot number (SIDC) Smoothed sunspot number Average ap
(3)
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)  
2008.07 65.7 (SF minimum) 0.5 2.8 (-0.4)  
2008.12 69.2 0.8 1.7 (-)
sunspot minimum
3.25
2009.03 69.2 0.7 2.0 (+0.1) 4.85
2009.04 69.7 0.8 2.2 (+0.2) 4.52
2009.05 70.5 2.9 2.3 (+0.1) 4.75
2009.06 68.6 2.9 2.7 (+0.4) 5.22
2009.07 68.2 3.2 3.6 (+0.9) 5.49 / 4.55
2009.08 67.3 0.0 4.8 (+1.2) 5.70 / 4.89
2009.09 70.5 4.3 6.1 (+1.3) 3.88 / 3.61
2009.10 72.6 4.8 7.0 (+0.9) 3.66 / 3.56
2009.11 73.6 4.1 7.6 (+0.6) 2.45 / 2.63
2009.12 76.7 10.8 (8.2 predicted, +0.6) 1.41 / 1.92
2010.01 81.1 13.1 (9.2 predicted, +1.0) 2.93 / 3.07
2010.02 84.7 18.6 (10.7 predicted, +1.5) 4.15 / 4.61
2010.03 83.4 15.4 (12.5 predicted, +1.8) 4.58 / 4.65
2010.04 75.9 7.9 (14.1 predicted, +1.6) 10.22 / 10.24
2010.05 73.8 8.8 (15.4 predicted, +1.3) 9.18 / 8.15
2010.06 71.9 (1) 8.0 (2) (16.9 predicted, +1.5) (7.63)

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz.
2) Current impact on the monthly SSN based on the Boulder (NOAA/SWPC) sunspot number (accumulated daily sunspots / month days). The official international sunspot number is typically 30-50% lower.
3) Running average based on the daily SWPC ap indices. Values in red are based on the official NGDC ap indices.

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.