Last major update issued on March 13, 2015 at 06:50 UT.
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[Noon SDO sunspot count 1K Reference: 4K (large file) (updated daily)]
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level October 2009 - December 2012]
[Solar polar fields vs solar cycles - updated February 21, 2015]
[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]
The geomagnetic field was quiet to unsettled on March 12. Solar wind speed at SOHO ranged between 363 and 416 km/s.
Solar flux at 20h UTC on 2.8 GHz was 126.7 (increasing 1.8 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 137.1. The Potsdam WDC planetary A index was 7 (STAR Ap - based on the mean of three hour interval ap indices: 6.8). Three hour interval K indices: 23222110 (planetary), 13333211 (Boulder).
The background x-ray flux is at the class B7 level.
At the time of counting spots (see image time), spots were observed in 6 active regions using 2K resolution (SN: 145) and 6 active regions using 1K resolution (SN: 107) SDO images on the visible solar disk.
Region 12296 [S12W53] decayed slowly and quietly.
Region 12297 [S16E03] has strong magnetic deltas both in the large trailing penumbra and in an intermediate section penumbra. The region became less compact as the intermediate and trailing spot sections became better separated. M and X class flares are possible.
New region 12299 [S07E63] emerged on March 11 and didn't display significant changes on March 12 when it was numbered by SWPC.
Spotted regions not numbered (or interpreted
differently) by SWPC:
S4276 [N15W36] was quiet and stable.
S4278 [N15E08] was quiet and stable.
S4280 [S16E28] developed slowly and quietly.
C2+ flares (GOES):
|Magnitude||Peak time (UTC)||Location||AR||Comment|
|C5.4||03:34||12299||added from SDO/EVE|
|C7.7||09:43||12299||added from SDO/EVE|
|C3.0||22:19||12297||added from SDO/EVE|
SDO/EVE/ESP XRS-B proxy
March 12: Again a day with incomplete LASCO coverage, however, no obvious
Earth directed CMEs were observed.
March 11: A filament eruption in the northwest quadrant beginning at 07:37 UT was associated with a CME off the northwest limb. No LASCO imagery after the X2 event in AR 12297 is available as this is written. In SDO/AIA imagery the flare appears to have been "dry", ie. not associated with a significant CME. Interesting filament activity was observed near center disc at the end of the day.
March 10: At least a partial halo CME was observed early in the day and was associated with the M5 event in AR 12297 late on March 9.
history (since October 2002)]
[Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago]
A recurrent coronal hole (CH658) rotated across the central meridian on March 9-10, CH658 has not been associated with geomagnetic disturbances during previous rotations.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet to unsettled on March 13-15. The CME observed early on March 10 may have had Earth directed extensions, consequently there is a chance of active intervals on March 13.
|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 green.
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: 0-30% probability, Yellow: 30-70% probability, Red: 70-100% 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
SWPC has added AR 12298 for these spots
|12298||2015.03.11||3||S11W52||0010||CRO||originally AR 12296|
|Total spot count:||26||85||47|
|Sunspot number:||56||145||107||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||42||107||69||(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):||34||51||59||k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for MSN 2K, k = 0.55 for MSN 1K (MSN=Magnetic Sunspot Number)|
|Month||Average solar flux||International sunspot number
|Smoothed sunspot number||Average
|166.3||102.3 (cycle peak)||78.4 (+1.1)||10.70|
(likely solar max)
|2014.09||146.6||148.1||87.6||(71.6 projected, -4.0)||9.78|
|2014.10||153.4||152.9||60.6||(69.2 projected, -2.4)||8.96|
|2014.11||154.8||151.4||70.1||(67.4 projected, -1.8)||9.33|
|2014.12||158.7||153.8||78.0||(66.3 projected, -1.1)||11.24|
|2015.01||141.9||137.3||67.0||(65.1 projected, -1.2)||9.46|
|2015.02||129.1||126.0||44.8||(63.6 projected, -1.5)||9.92|
|2015.03||(127.1)||15.9 (2A) / 41.0 (2B) / 54.9 (2C)||(61.6 projected, -2.0)||(11.7)|
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 WDC-SILSO 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 GFZ Potsdam WDC ap indices.
This report has been prepared by Jan Alvestad. It is based on the 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.