Last major update issued on July 11, 2011 at 04:40 UTC. Minor update posted at 19:35 UTC
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The geomagnetic field was quiet to active on July 10. Solar wind speed ranged between 432 and 559 km/s under the influence of a high speed stream from CH464 (CH464 replaced CH463 as the dominant solar wind source after approximately 04h UTC).
Solar flux measured at 20h UTC on 2.8 GHz was 90.7 (increasing 4.1 over the last solar rotation). The planetary A index was 12 (STAR Ap - based on the mean of three hour interval ap indices: 11.8). Three hour interval K indices: 34312322 (planetary), 34312323 (Boulder).
The background x-ray flux is at the class B2 level.
At midnight UTC the visible solar disk had 9 spotted regions.
Region 11245 was quiet and stable.
Region 11247 was quiet. The region has developed a magnetic delta structure in the central penumbra. Further development will increase the likelihood of C flares and maybe a minor M class flare.
Region 11249 developed slowly and quietly.
New region 11250 emerged quickly in the southeastern quadrant on July 10.
Spotted regions not numbered by NOAA/SWPC:
[S1107] rotated partly into view at the northeast limb on July 10. Location at midnight: N16E83
[S1108] emerged in the northeast quadrant on July 10. Location at midnight: N22E33
[S1109] emerged in the northeast quadrant on July 10. Location at midnight: N23E23
[S1110] emerged in the southeast quadrant on July 10. Location at midnight: S28E32
[S1111] emerged near the center of the visible disk on July 10. Location at midnight: S06W01
Minor update added at 19:35 UTC on July 11: The CME observed early on June 9 reached Earth sooner than expected, SOHO observed a solar wind shock at 08:05 UTC. Since then the geomagnetic field has been unsettled to active.
July 8 and 10: No obviously earth directed CMEs were observed.
July 9: A long duration B4 event peaking near 01h UTC was associated with a filament eruption to the east of region 11247. A CME was observed and there's a fair chance this CME will reach Earth on July 12.
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.
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 unsettled on July 11 due to a high speed stream from CH464. A weak CME could reach Earth on July 12 and cause a few unsettled and active intervals. A disturbance associated with CH465 may cause quiet to active conditions on July 13-14 becoming quiet to unsettled 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:||27||50|
|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||86.1 (1)||15.7 (2A) / 48.6 (2B)||(49.4 predicted, +4.1)||(9.90)|
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.