Last major update issued on March 2, 2013 at 06:35 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 active to minor storm on March 1. Solar wind speed at SOHO ranged between 348 and 615 km/s under the influence of a high speed stream from CH556.
Solar flux measured at 20h UTC on 2.8 GHz was 112.6 (increasing 0.8 over the last solar rotation). The Potsdam WDC planetary A index was 33 (STAR Ap - based on the mean of three hour interval ap indices: 33.0). Three hour interval K indices: 44455444 (planetary), 54354433 (Boulder).
The background x-ray flux was at the class B3 level.
At midnight UTC the visible solar disk had 9 spotted active regions (in 2K resolution SDO images).
Region 11680 [S29W13] was quiet and stable.
Region 11681 [N17E09] was quiet. Two new spots emerged in the easternmost part of the leading polarity area. SWPC / USAF chose to number these spots as AR 11684.
Region 11682 [S19W42] was quiet and stable. Opposite polarity penumbra spots are poorly separated in the southern part of the trailing spot section.
Region 11683 [S16E56] added spots and has minor polarity intermixing. C flares are possible with a low chance for a minor M class event.
New region 11685 [S15E75] rotated partly into view on February 28 and was numbered the next day by SWPC.
Spotted regions not numbered by SWPC:
S2253 [N41W20] reemerged with a penumbra spot in the northeasternmost part of the trailing polarity area.
S2261 [S10E23] reemerged with penumbra spots.
New region S2263 [S23W50] emerged to the south of AR 11682.
New region S2264 [S19E37] emerged with a penumbra spot.
February 27 - March 1: 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 recurrent trans equatorial coronal hole (CH556) was in an Earth facing position on February 26-28. A northern hemisphere coronal hole (CH557) was in a geoeffective position on March 1. A southern hemisphere coronal hole (CH558) will likely rotate into an Earth facing position on March 3.
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 fair to good.
The geomagnetic field is expected to be unsettled to active on March 2 and quiet to active on March 3-5 due to effects from CH556 and CH557. Another disturbance, associated with CH558, could start on March 6.
|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
|11684||2013.03.01||2||N18E13||0010||AXX||part of AR 11681|
|Total spot count:||28||72||34|
|Sunspot number:||88||162||84||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||41||91||53||(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):||53||57||46||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)||5.48|
|2013.03||112.6 (1)||2.8 (2A) / 88.0 (2B) / 41.5 (2C)||(51.5 projected, -1.0)||(33.0)|
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.