Last major update issued on March 15, 2011 at 05:10 UTC.
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The geomagnetic field was quiet on March 14. Although the main solar wind influence was CH439, the interplanetary magnetic field was predominantly northwards.
Solar flux measured at 20h UTC on 2.8 GHz was 107.4 (decreasing 5.4 over the last solar rotation). The planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 2.9). Three hour interval K indices: 11100011 (planetary), 11110110 (Boulder).
The background x-ray flux is at the class B4 level.
At midnight UTC the visible solar disk had 6 spotted regions.
Region 11166 decayed further and will rotate over the northwest limb
today. Flare: C4.0 at 00:20 UTC.
Region 11169 lost the spots in the northeastern part of the region. There is still a magnetic delta structure at the southern edge of the main penumbra. Another M class flare is possible. Flares: C1.0 at 05:08, C2.2 at 16:09, M4.2/1N at 19:52, C5.2 at 23:37 UTC. The region was the source of an impulsive M1.0 flare at 00:22 UTC.
Region 11171 was quiet and stable.
Region 11172 finally developed spots in both polarities. Flare: C1.4 at 08:15 UTC.
Spotted regions not numbered by NOAA/SWPC:
[S902] The spots in the southern part of the region disappeared while a new spot emerged in the northern part. Location at midnight: N21W15.
[S904] A new region emerged in the southeast quadrant on March 13 and decayed slightly on March 14. Location a midnight: S24E09
March 12-14: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
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 small coronal hole (CH440) in the northern hemisphere will be in an Earth facing position on March 15.
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 poor to fair. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet on March 15-19 with a possibility of unsettled intervals on March 18-19 due to effects from CH440.
|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
|11171||2011.03.08||4||S19W15||0000||BXO||location of spots: S20W20|
|Total spot count:||21||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)|
|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||127.8 (1)||43.2 (2A) / 95.6 (2B)||(33.0 predicted, +1.9)||(12.96)|
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.