Last major update issued on March 28, 2011 at 04:10 UTC.
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Annotated geomagnetic activity charts - Carrington rotation 2106 [Jan.-Feb.2011] - 2107 [Feb.-March 2011] NEW
The geomagnetic field was quiet on March 27. Solar wind speed ranged between 310-369 km/s.
Solar flux estimated at 20h UTC on 2.8 GHz was 117 (increasing 21.2 over the last solar rotation). The planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 2.1). Three hour interval K indices: 00001111 (planetary), 00000012 (Boulder).
The background x-ray flux is at the class B3 level.
At midnight UTC the visible solar disk had 9 spotted regions.
Region 11176 decayed slowly losing spots becoming less complex.
Flare: C3.1 at 00:14 UTC.
Region 11177 was quiet and stable.
Region 11178 decayed slowly and was quiet.
Region 11180 was quiet and stable.
Region 11181 added a few spots and was quiet.
New region 11182 emerged as region S919 on March 24, lost its spots the following day. A couple of tiny spots reemerged on March 27.
New region 11183 rotated partly into view on March 26 and was numbered the next day by NOAA/SWPC. The region may be capable of producing an M class flare.
Spotted regions not numbered by NOAA/SWPC:
[S915] emerged on March 22, became spotless, then reemerged on March 27 with a few spots. Location at midnight: S14W62
[S923] emerged on March 27 west of region 11181. Location at midnight: S26E38.
March 25-27: No obviously Earth directed CMEs were observed in LASCO
and STEREO imagery.
March 24: A small partial halo CME was observed in association with an M1 flare in region 11176.
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
No obvious coronal holes are currently in or near Earth facing positions.
The darkest areas on the solar disk are likely coronal holes.
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.
The geomagnetic field is expected to be quiet on March 28-30. On March 28 there's a chance of unsettled and active intervals if the CME observed on March 24 reaches Earth.
|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||2||N13E01||0000||AXX||BXO||formerly region S919|
formerly region S921
|Total spot count:||52||101|
|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)|
|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||16.8 (+0.4)||6.31 / 5.15|
|2010.08||79.2||19.6||17.4 (+0.6)||8.49 / 7.77|
|2010.09||81.1||25.2||(19.1 predicted, +1.7)||5.33 / 5.45|
|2010.10||81.6||23.5||(21.7 predicted, +2.6)||6.07 / 6.27|
|2010.11||82.5||21.6||(24.5 predicted, +2.8)||4.80 / 5.50|
|2010.12||84.2||14.5||(26.9 predicted, +2.4)||3.41 / 4.35|
|2011.01||83.6||19.1||(29.0 predicted, +2.1)||4.32|
|2011.02||94.6||29.4||(31.1 predicted, +2.1)||5.41|
|2011.03||114.8 (1)||68.9 (2A) / 79.1 (2B)||(33.0 predicted, +1.9)||(8.39)|
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.