Last major update issued on June 3, 2011 at 04:55 UTC.
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The geomagnetic field was quiet to unsettled on June 2. Solar wind speed ranged between 443 and 480 km/s under the diminishing influence of a high speed stream from CH451.
Solar flux measured at 20h UTC on 2.8 GHz was 111.6 (increasing 9.7 over the last solar rotation). The planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.1). Three hour interval K indices: 22322122 (planetary), 22333221 (Boulder).
The background x-ray flux is at the class B3 level.
At midnight UTC the visible solar disk had 9 spotted regions.
Region 11225 was quiet and stable.
Region 11226 developed in the southern spot section with penumbra forming on the trailing polarity. Flares: C1.2 at 02:44, C2.7/1F at 09:47 UTC.
Region 11227 decayed slowly and was quiet.
Region 11228 was quiet and decayed slowly.
Region 11229 decayed slowly and was quiet.
Region 11230 was quiet and stable.
Region 11231 was reassigned to region S1043 (which emerged in the northeast quadrant on June 1).
New region 11232 was AR 11231 on June 1 and got a new number from SWPC on June 2.
Spotted regions not numbered by NOAA/SWPC:
[S1044] was split off from region 11227 on June 1. Location at midnight: S19E11. Flares: C1.4 at 06:36 and C3.7/2N at 07:46 UTC. The latter event was associated with a type IV radio sweep and a slow full halo CME where most of the ejected material was in the trans equatorial area between S1044 and AR 11228.
May 31: No obviously Earth directed CMEs were observed in LASCO
and STEREO imagery.
June 1: A slow full halo CME was observed after the C4 event at 17:08 UTC in and to the north of region 11226.
June 2: A slow full halo CME was observed in association with the C3 event at 07:46 UTC to the north of region S1044.
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
The southernmost extension of a large coronal hole (CH452) in the northern hemisphere was in an Earth facing position on May 30-31.
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.
The geomagnetic field is expected to be quiet to active on June 3 due to effects from CH452. The CME observed on June 1 could arrive on June 4 or 5 and cause unsettled to minor storm conditions while the CME observed on June 2 likely will arrive on June 5.
|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
|1||3||N10E61||0080||HSX||CSO||SWPC reassigned number on June 2
|4||7||N08E50||0090||CRO||BXO||formerly region S1043
|S1044||2011.06.01||6||S19E11||0030||CRO||split off from 11227 on June 1|
|Total spot count:||38||92|
|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)|
|2010.02||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||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||(29.4 predicted, +2.9)||3.41 / 4.35|
|2011.01||83.6||19.1||(32.6 predicted, +3.2)||4.32 / 5.51|
|2011.02||94.6||29.4||(35.2 predicted, +2.6)||5.41 / 6.44|
|2011.03||115.0||56.2||(37.5 predicted, +2.3)||7.79|
|2011.04||112.6||54.4||(40.4 predicted, +2.9)||9.71|
|2011.05||95.8||41.6||(43.7 predicted, +3.3)||9.18|
|2011.06||112.6 (1)||7.5 (2A) / 112.5 (2B)||(47.4 predicted, +3.7)||(10.0)|
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.