Solar Terrestrial Activity Report

Last major update issued on June 10, 2010 at 04:30 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 9. Solar wind speed ranged between 287 and 389 km/s. A weak coronal hole based disturbance is in progress early on June 10.

Solar flux measured at 20h UTC on 2.8 GHz was 71.5. The planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.4). Three hour interval K indices: 11111212 (planetary), 11111212 (Boulder).

The background x-ray flux is at the class A5 level.

At midnight there were 3 spotted regions on the visible solar disk.

Region 11078 added penumbral area but appears to be magnetically less complex. C flares are possible. The region has reversed polarities and minor polarity intermixing.
New region 11079 emerged in the southwest quadrant on June 8 and was numbered the following day by NOAA/SWPC. Slow development was observed on June 9.

Spotted regions not numbered by NOAA/SWPC:
[S777] This region emerged in the southwest quadrant on June 9. Location at  midnight: S23W26

Coronal mass ejections (CMEs)

June 7-9: No obvious Earth directed CMEs were observed in LASCO or STEREO images.

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 likely rotate into an Earth facing position on June 12-13.

Processed SOHO/EIT 195 image at 00:00 UTC on June 10. 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. Propagation on long distance northeast-southwest paths is fair.

Forecast

The geomagnetic field is expected to be quiet to unsettled on June 10 and quiet on June 11-12.

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 6 9 S21W60 0180 DSI classification was DAI at midnight
reversed polarity
beta-gamma
S775 2010.06.07     N15W06     plage
11079 2010.06.09 2 1 S26W36 0010 BXO formerly region S776
classification was AXX at midnight
S777 2010.06.09   2 S23W26 0000 BXO  
Total spot count: 8 12  
SSN: 28 42  

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 71.5 (1) 5.2 (2) (16.9 predicted, +1.5) (8.17)

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.