Last major update issued on July 13, 2011 at 05:00 UTC. Minor update posted at 19:05 UTC.
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Annotated geomagnetic activity charts - Carrington rotation 2110 [May-June 2011] - 2111 [June-July 2011] NEW
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The geomagnetic field was quiet to unsettled on July 12. Solar wind speed ranged between 627 and 774 km/s under the influence of a high speed stream from CH464.
Solar flux measured at 20h UTC on 2.8 GHz was 91.7 (decreasing 9.8 over the last solar rotation). The planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 7.9). Three hour interval K indices: 33012222 (planetary), 33122321 (Boulder).
The background x-ray flux is at the class B2 level.
At midnight UTC the visible solar disk had 10 spotted regions.
Region 11245 decayed slowly and quietly.
Region 11247 decayed further. Flare: C1.9 at 14:49 UTC
Region 11249 decayed slowly and quietly.
Region 11250 was quiet and stable.
Region 11251 was quiet and stable.
Spotted regions not numbered by NOAA/SWPC:
[S1108] emerged in the northeast quadrant on July 10. Location at midnight: N21E07
[S1112] emerged in the northeast quadrant on July 11. Location at midnight: N08E36
[S1113] rotated into view at the northeast limb on July 12. Location at midnight: N17E73
[S1114] rotated into view at the northeast limb on July 12. Location at midnight: N25E84
[S1115] emerged in the northeast quadrant on July 12. Location at midnight: N16E22
Minor update added at 19:05 UTC: As you can see in the latest high resolution STAR CHARMAP, several new regions have become visible today while regions 11249 and 11247 could become spotless before midnight UTC.
July 10 and 12: No obviously earth directed CMEs were observed.
July 11: A small CME was observed after a C2.6 flare in region 11249. The CME could reach Earth late on July 13.
Coronal hole history (since late October
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago
A recurrent coronal hole (CH464) in the southern hemisphere was Earth facing on July 7-8. A trans equatorial coronal hole (CH465) was Earth facing on July 10-11. A large trans equatorial coronal hole (CH466) will likely become Earth facing on July 16-17.
The above coronal hole map is based on a new method where coronal holes are detected automatically. The method may need some fine tuning, however, it has significant advantages over detecting coronal holes manually. The main improvement is the ability to detect coronal holes at and just beyond the solar limbs. Early results using this method for SDO images over a span of several weeks indicate a good match between coronal holes observed over the visible disk and their extent and position at the east and west limbs. Note that the polar coronal holes are easily detected using the new method, the extent and intensity of both holes are consistent with other data sources.
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 to good.
The geomagnetic field is expected to be quiet to active on July 13-14. A high speed stream from CH465 will likely arrive during the first half of July 13 while a weak CME impact is possible late in the day or early on July 14. Quiet to unsettled is likely on July 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
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.
(Click on image for higher resolution image) Compare to the previous day's image
When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue (blue-green) is positive.
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 / HMI 4K continuum
image with polarity overlay
|Total spot count:||12||38|
|Month||Average measured solar flux||International sunspot number (SIDC)||Smoothed sunspot number||Average ap
|2008.07||65.7 (SF minimum)||0.5||2.8 (-0.4)|
|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||16.7 (+0.3)||6.31 / 5.15|
|2010.08||79.2||19.6||17.4 (+0.7)||8.49 / 7.77|
|2010.09||81.1||25.2||19.6 (+2.2)||5.33 / 5.45|
|2010.10||81.6||23.5||23.2 (+3.6)||6.07 / 6.27|
|2010.11||82.5||21.5||26.5 (+3.3)||4.80 / 5.50|
|2010.12||84.2||14.4||28.8 (+2.3)||3.41 / 4.35|
|2011.01||83.6||19.1||(30.6 predicted, +1.8)||4.32 / 5.51|
|2011.02||94.6||29.4||(32.6 predicted, +2.0)||5.41 / 6.44|
|2011.03||115.0||56.2||(35.2 predicted, +2.6)||7.79 / 8.18|
|2011.04||112.6||54.4||(38.1 predicted, +2.9)||9.71 / 8.83|
|2011.05||95.8||41.6||(41.4 predicted, +3.3)||9.18 / 8.94|
|2011.06||95.8||37.0||(45.2 predicted, +3.8)||8.96|
|2011.07||86.9 (1)||20.0 (2A) / 51.7 (2B)||(49.4 predicted, +4.1)||(10.02)|
1) Running average based on the daily 20:00 UTC observed solar flux value at
2A) Current impact on the monthly sunspot number based on the Boulder (NOAA/SWPC) sunspot number (accumulated daily sunspots / month days). The official SIDC 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.