Solar Terrestrial Activity Report

Last major update issued on January 15, 2011 at 07:05 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-24 (last update January 2, 2011)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update January 2, 2011)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update January 2, 2011)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports from January 2003 (last update January 1, 2011)]

[POES auroral activity level charts since October 2009]
[Annotated geomagnetic activity chart - Carrington rotation 2104 - NEW]

Recent activity

The geomagnetic field was quiet to unsettled on January 14. Solar wind speed ranged between 452 and 572 km/s under the influence of a high speed coronal hole stream from CH433.

Solar flux measured at 20h UTC on 2.8 GHz was 79.3 (down 1.2 over the last solar rotation). The planetary A index  was 7 (STAR Ap - based on the mean of three hour interval ap indices: 7.0). Three hour interval K indices: 12212312 (planetary), 11222321 (Boulder).

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

At midnight UTC the visible solar disk had 1 spotted region.

Region 11145 reemerged with a couple of small spots.

An active region just behind the northeast limb produced 2 C flares, a C1.6 long duration event peaking at 03:30 and a C1.0 flare at 13:07 UTC.

Coronal mass ejections (CMEs)

January 12-14: No obviously 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 (CH433) was in an Earth facing position on January 9-12. A poorly defined coronal hole (CH434) will rotate into an Earth facing position on January 15-16.

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 fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet to unsettled on January 15 due to effects from CH433 and quiet on January 16-18. On January 19-20 weak effects from CH434 are possible.

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 Spot count Location at midnight Area Classification SDO (NASA) / AIA 4500
image
Comment
SWPC STAR SWPC STAR Current Previous
11145 2011.01.09 1 2 N16W25 0000 AXX BXO    
11146 2011.01.10     N23W09        

plage

Total spot count: 1 2  
Sunspot number: 11 12  

Monthly solar cycle data

Month Average measured solar flux International sunspot number (SIDC) Smoothed sunspot number Average ap
(3)
2008.07 65.7 (SF minimum) 0.5 2.8 (-0.4)  
2008.12 69.2 0.8 1.7 (-)
sunspot minimum
3.25
2009.10 72.6 4.8 7.1 (+0.9) 3.66 / 3.56
2009.11 73.6 4.1 7.6 (+0.5) 2.45 / 2.63
2009.12 76.7 10.8 8.3 (+0.7) 1.41 / 1.92
2010.01 81.1 13.2 9.3 (+1.0) 2.93 / 3.07
2010.02 84.7 18.8 10.6 (+1.3) 4.15 / 4.61
2010.03 83.4 15.4 12.3 (+1.7) 4.58 / 4.65
2010.04 75.9 8.0 14.0 (+1.7) 10.22 / 10.24
2010.05 73.8 8.7 15.5 (+1.5) 9.18 / 8.15
2010.06 72.5 13.6 16.4 (+0.9) 8.17 / 6.85
2010.07 79.8 16.1 (17.0 predicted, +0.6) 6.31 / 5.15
2010.08 79.2 19.6 (17.9 predicted, +0.9) 8.49 / 7.77
2010.09 81.1 25.2 (19.0 predicted, +1.1) 5.33 / 5.45
2010.10 81.6 23.5 (20.7 predicted, +1.7) 6.07 / 6.27
2010.11 82.5 21.6 (23.0 predicted, +2.3) 4.80
2010.12 84.2 14.5 (25.3 predicted, +2.3) 3.41
2011.01 85.6 (1) 17.7 (2A) / 39.2 (2B) (27.7 predicted, +2.4) (5.34)

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz.
2A) Current impact on the monthly sunspot number based on the Boulder (NOAA/SWPC) sunspot number (accumulated daily sunspots / month days). The official international sunspot number is typically 30-50% lower. 2B) Month average to date.
3) Running average based on the preliminary 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 on analysis of data from whatever sources are available at the time the report is prepared. All time references are to the UTC day. Comments and suggestions are always welcome.

SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.