Last major update issued on March 10, 2012 at 05:10 UTC. Minor update posted at 20:50 UTC
[Solar and geomagnetic data - last month (updated
[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-24 (last update March 2, 2012)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update March 2, 2012)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update March 2, 2012)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update March 1, 2012)]
[POES auroral activity level since October
2009 - updated March 5, 2012]
Annotated geomagnetic activity charts - Carrington rotation 2118 [December 2011 - January 2012] - 2119 [January-February 2012]
[Solar polar fields vs solar cycles - updated June 27, 2011]
The geomagnetic field was unsettled to very severe storm on March 9. Solar wind speed at SOHO ranged between 525 and 986 km/s under the influence of a CME. The disturbance reached its maximum during the 07-10, 08-11 and 10-13h UTC intervals when the planetary A index was 207.
Solar flux measured at 20h UTC on 2.8 GHz was 145.5 (increasing 33.2 over the last solar rotation). The planetary A index was 94 (STAR Ap - based on the mean of three hour interval ap indices: 93.5. The running average of the one hour increment 3-hour ap indices was 99.8). Three hour interval K indices: 56887633 (planetary), 55785532 (Boulder).
The background x-ray flux is at the class B8 level.
At midnight UTC the visible solar disk had 9 spotted active regions (in 2K resolution SDO images).
Region 11428 [S17W31] added some spots in the southern trailing spot
section. The region has weak polarity
intermixing. Flare: C5.1 at 21:50 UTC
Region 11429 [N17W10] decayed slowly and has only one magnetic delta structure left in the trailing spot section. The region is probably still capable of producing another major flare. Flare: major M6.3 long duration event peaking at 03:53 UTC. This event was associated with a full halo CME.
Region 11430 [N20W27] decayed further losing spots and has no penumbra left on the trailing spots.
Region 11431 [S28W86] added spots and was quiet.
New region 11432 [N15E68] rotated into view at the northeast limb on March 8 and was numbered the next day by SWPC. The region is complex with a magnetic delta structure in the leading penumbra. M flares are possible. Flare: C9.7 at 20:25 UTC.
Spotted regions not reported by NOAA/SWPC:
[S1505] reemerged with tiny spots on March 9. Location at midnight: S26W43
[S1517] emerged in the southeast quadrant on March 9. Location at midnight: S23E24
[S1520] emerged in the northeast quadrant on March 9. Location at midnight: N27E22
[S1521] emerged in the southwest quadrant on March 9. Location at midnight: S32W29
Minor update added at 20:50 UTC: AR 11430 produced a long duration C8.0 event peaking at 15:52 UTC. The event and the associated CME appears to have triggered the major M8.4 long duration event peaking at 17:44 UTC in AR 11429. An impressive CME was observed in STEREO imagery after the M8 event. The CME could reach Earth on March 12 and cause unsettled to severe storm conditions. Otherwise new regions with spots have rotated into view at the northeast limb while spots are emerging in a new region near the southeast limb.
March 7: The X flares in region 11429 produced full halo CMEs which
reached Earth on March 8.
March 8: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
March 9: The M6 event in region 11429 produced a full halo CME. This CME could reach Earth late on March 10 or early on March 11.
Coronal hole history (since October
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago
A large recurrent trans equatorial coronal hole (CH507) will likely rotate in an Earth facing position on March 13-14.
The above coronal hole map is based on a method where coronal holes are detected automatically. While the method may need some fine tuning, 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 this method, the extent and intensity of both CHs 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 very poor. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be unsettled to minor storm most of March 10. Late in the day or early on March 11 another CME impact is likely and could cause active to severe storm conditions. Quiet to minor storm is possible on March 12.
|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 magnetic polarity overlay
|Total spot count:||46||127||47|
|Sunspot number:||96||217||107||(total spot count + 10 * number of spotted regions)|
|Weighted penumbral SN:||74||155||75||(Sum of total spot count + classification weighting for each AR. Classification weighting: X=0, R=3, A/S=5, H/K=10)|
|Relative sunspot number (Wolf number):||52||76||59||k * (sunspot number). k = 0.6 for SWPC, k = 0.35 (changed from 0.45 on March 1, 2011) for STAR SDO 2K, k = 0.55 for STAR SDO 1K|
|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)|
|2010.12||84.2||14.4||28.8 (+2.3)||3.41 / 4.35|
|2011.01||83.6||19.1||31.0 (+2.2)||4.32 / 5.51|
|2011.02||94.6||29.4||33.4 (+2.4)||5.41 / 6.44|
|2011.03||115.0||56.2||36.9 (+3.5)||7.79 / 8.18|
|2011.04||112.6||54.4||41.8 (+4.9)||9.71 / 8.83|
|2011.05||95.8||41.6||47.6 (+5.8)||9.18 / 8.94|
|2011.06||95.8||37.0||53.2 (+5.6)||8.96 / 8.06|
|2011.07||94.2||43.9||57.2 (+4.0)||9.14 / 8.16|
|2011.08||101.7||50.6||59.0 (+1.8)||8.16 / 7.26|
|2011.09||133.8||78.0||(59.2 projected, +0.2)||12.80 / 12.27|
|2011.10||137.3||88.0||(59.4 projected, +0.2)||7.52 / 8.28|
|2011.11||153.5||96.7||(60.8 projected, +1.4)||4.58 / 5.55|
|2011.12||141.3||73.0||(63.6 projected, +2.8)||3.32|
|2012.01||132.5||58.3||(67.1 projected, +3.5)||6.59|
|2012.02||106.5||33.1||(71.0 projected, +3.9)||8.09|
|2012.03||126.0 (1)||21.5 (2A) / 74.2 (2B)||(73.2 projected, +2.2)||(27.92)|
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.