Last major update issued on March 12, 2015 at 04:15 UT.
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[Noon SDO sunspot count 1K Reference: 4K (large file) (updated daily)]
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[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]
The geomagnetic field was quiet to unsettled on March 11. Solar wind speed at SOHO ranged between 365 and 443 km/s.
Solar flux at 20h UTC on 2.8 GHz was 131.7 (increasing 4.1 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 137.4. The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 7.8). Three hour interval K indices: 13212321 (planetary), 13223322 (Boulder).
The background x-ray flux is at the class C1 level.
At the time of counting spots (see image time), spots were observed in 9 active regions using 2K resolution (SN: 189) and 7 active regions using 1K resolution (SN: 103) SDO images on the visible solar disk.
Region 12296 [S12W39] decayed in the trailing spots
section while slow developedment was observed in the leading polarity spots.
Region 12297 [S16E16] developed further and has a strong magnetic delta in the large trailing penumbra. Further X class flares are possible.
Spotted regions not numbered (or interpreted
differently) by SWPC:
S4262 [N15W42] was quiet and stable.
S4270 [S22W12] decayed slowly and quietly.
S4273 [N11E35] reemerged with penumbra spots.
S4276 [N16W22] was quiet and stable.
New region S4278 [N15E19] was observed with penumbra spots.
New region S4279 [S06E77] emerged at the southeast limb with a few spots.
New region S4280 [S15E42] emerged with penumbra spots.
C2+ flares (GOES):
|Magnitude||Peak time (UTC)||Location||AR||Comment|
|C5.8||00:23||12297||added from SDO/EVE|
|C6.7||23:45||12297||triggered strong center disk filament activity|
SDO/EVE/ESP XRS-B proxy
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.
March 9: No obviously Earth directed CMEs were observed in LASCO imagery.
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 12-14. 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)|
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||S11W38||0010||BXO||originally AR 12296|
|Total spot count:||22||99||43|
|Sunspot number:||42||189||103||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||32||115||59||(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):||25||66||57||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||(127.2)||14.1 (2A) / 39.6 (2B) / 55.3 (2C)||(61.6 projected, -2.0)||(12.2)|
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.