Last major update issued on March 15, 2013 at 04:55 UTC. Minor update posted at 16:30 UTC.
[Solar and geomagnetic data - last month (updated
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update March 1, 2013)] [Cycle 24 progress (last update March 2, 2013) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update March 1, 2013)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update March 1, 2013)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update March 1, 2013)]
[POES auroral activity level since October
2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated February 3, 2013]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]
The geomagnetic field was quiet on March 14. Solar wind speed at SOHO ranged between 276 and 419 km/s. Solar wind speed increased slowly after noon, likely due to the arrival of a low speed stream from CH559. The interplanetary magnetic field was mostly northwards resulting in only a minor increase in geomagnetic activity. A weak solar wind shock was observed near 04:40 UTC on March 15, the likely arrival of a CME observed on March 12.
Solar flux measured at 20h UTC on 2.8 GHz was 122.8 (increasing 19.6 over the last solar rotation). The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 4.8). Three hour interval K indices: 11112111 (planetary), 01013222 (Boulder).
The background x-ray flux was at the class B3 level.
At midnight UTC the visible solar disk had 11 spotted active regions (in 2K resolution SDO images).
Region 11689 [S18W71] decayed slowly and quietly.
Region 11690 [N24W35] was quiet and stable.
Region 11691 [N12W40] decayed slowly with polarity intermixing disappearing during the day.
Region 11692 [N09E10] was quiet and stable.
Region 11694 [N15E12] was quiet and stable.
Region 11695 [N09E33] was quiet and stable.
Region 11696 [N04W08] decayed slowly and quietly.
New region 11697 [N14W22] emerged on March 13 and was numbered the next day by SWPC.
New region 11698 [S19W29] emerged quickly and has polarity intermixing.
Spotted regions not numbered by SWPC:
S2278 [S16W46] lost the spots from the previous day and gained a spot further west.
New region S2291 [S13W26] emerged with penumbra spots.
Update added at 16:30 UTC on March 15: AR 11692 produced a long duration M1.1/1F event peaking at 06:58 UTC. This event was associated with a large and wide full halo CME in STEREO A/B and LASCO. The CME could reach Earth on March and cause minor to severe geomagnetic storming.
March 12: A weak partial halo CME was observed in LASCO imagery from the
combined ejecta of the C2 LDE near the central meridian and a filament eruption
in the northeast quadrant. The CME may have had a weak Earth directed component.
March 13: A CME was observed off the east limbs early in the day following a filament eruption near ARs 11696 and 11692 late on March 12. No obvious Earth bound components were observed.
March 14: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
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 small northern hemisphere coronal hole (CH559) was in an Earth facing position on March 11. A small coronal hole (CH560) in the southern hemisphere was Earth facing on March 14 but seemed to be closing by the end of the day.
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 to unsettled on March 15 due with a chance of active intervals if the CME observed on March 12 arrives. Quiet to unsettled consitions are likely on March 16-17. A few unsettled intervals are possible on March 18 due to effects from CH560.
|Coronal holes (1)||Coronal mass ejection (2)||M and X class flares (3)|
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 2K resolution) Compare to the previous day's image. 0.5k image
When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue 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:||43||86||31|
|Sunspot number:||133||196||111||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||75||122||67||(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):||80||69||61||k * (sunspot number). k = 0.6 for SWPC, k = 0.35 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
|2011.11||153.5 (cycle max)||96.7 (cycle max)||61.1 (+1.2)||5.55|
possible cycle 24 max
|2012.09||122.9||61.4||(57.9 projected, -0.2)||8.07|
|2012.10||123.3||53.3||(57.0 projected, -0.9)||9.97|
|2012.11||121.3||61.4||(56.1 projected, -0.9)||7.08|
|2012.12||108.6||40.8||(54.9 projected, -1.2)||3.44|
|2013.01||127.1||62.9||(53.6 projected, -1.3)||4.69|
|2013.02||104.3||38.0||(52.5 projected, -1.1)||6.11|
|2013.03||116.8 (1)||42.5 (2A) / 94.1 (2B) / 48.8 (2C)||(51.5 projected, -1.0)||(7.29)|
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) Boulder SN current month average to date. 2C) STAR SDO 1K Wolf number 30 day average.
3) Running average based on the quicklook and definitive Potsdam WDC ap indices. Values in red are based on the definitive international Potsdam WDC 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.