Last major update issued on March 16, 2013 at 06:50 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 to unsettled on March 15. Solar wind speed at SOHO ranged between 321 and 469 km/s. A weak solar wind shock was observed at 04:46 UTC at SOHO on March 15, likely the arrival of a CME observed on March 12.
Solar flux measured at 20h UTC on 2.8 GHz was 123.1 (increasing 17.6 over the last solar rotation). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 5.9). Three hour interval K indices: 13221001 (planetary), 03321201 (Boulder).
The background x-ray flux was at the class B5 level.
At midnight UTC the visible solar disk had 16 spotted active regions (in 2K resolution SDO images).
Region 11689 [S19W71] decayed slowly with only a single trailing spot
Region 11691 [N12W53] decayed slowly and quietly.
Region 11692 [N09W03] was mostly unchanged and produced the only interesting event of the day, a long duration M1.1/1F event peaking at 06:58 UTC. A wide full halo CME was observed in STEREO A/B and LASCO.
Region 11694 [N15W02] decayed slowly and quietly.
Region 11695 [N09E19] was quiet and stable.
Region 11696 [N04W23] decayed slowly and was mostly quiet.
Region 11697 [N15W35] was quiet and stable.
Region 11698 [S19W44] developed further and still has polarity intermixing.
Spotted regions not numbered by SWPC:
New region S2292 [S26E49] emerged with several spots.
New region S2293 [S13E80] rotated into view.
New region S2294 [N15E42] emerged with tiny spots.
New region S2295 [S24W16] emerged with a penumbra spot.
New region S2296 [N03W08] emerged with penumbra spots.
New region S2297 [N13W10] emerged to the west of AR 11694 with several spots.
New region S2298 [N09W47] emerged to the southeast of AR 11691.
New region S2299 [N19E71] rotated into view.
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.
March 15: A symmetrical full halo CME was observed after the M1.1 LDE in AR 11692. The CME will likely reach Earth on March 17.
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 coronal hole (CH560) in the southern hemisphere was Earth facing on March 14.
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 poor to fair.
The geomagnetic field is expected to be quiet to active on March 16. The CME expected to arrive on March 17 could cause minor to major storm levels with a chance of severe storm intervals. Quiet to minor storm conditions are likely on March 18.
|Coronal holes (1)||Coronal mass ejection (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 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:||35||103||46|
|Sunspot number:||105||263||156||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||68||141||84||(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):||63||92||86||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||117.2 (1)||45.6 (2A) / 94.8 (2B) / 50.8 (2C)||(51.5 projected, -1.0)||(7.20)|
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.