Last major update issued on March 11, 2015 at 04:35 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 on March 10. Solar wind speed at SOHO ranged between 355 and 394 km/s.
Solar flux at 20h UTC on 2.8 GHz was 120.9 (decreasing 10.2 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 137.5. The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.5). Three hour interval K indices: 11210011 (planetary), 12232221 (Boulder).
The background x-ray flux is at the class B5 level.
At the time of counting spots (see image time), spots were observed in 7 active regions using 2K resolution (SN: 132) and 7 active regions using 1K resolution (SN: 99) SDO images on the visible solar disk.
Region 12296 [S11W22] developed as new flux emerged
inside the trailing polarity area.
Region 12297 [S16E29] gained area and lost some spots as most spots merged with the major penumbrae. The region has multiple magnetic deltas and an X class flare is possible.
Spotted regions not numbered (or interpreted
differently) by SWPC:
S4256 [S12W67] was quiet and stable.
S4262 [N14W31] was quiet and stable.
S4270 [S28W02] was quiet and stable.
New region S4276 [N15W09] emerged with a few spots.
New region S4277 [S12E12] was observed with a penumbra spot.
C2+ flares (GOES):
|Magnitude||Peak time (UTC)||Location||AR||Comment|
|M2.9||00:02||S16E28||12297||flare began at 23:46 UT and peaked the next day|
SDO/EVE/ESP XRS-B proxy
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 8-9: 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 to fair. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet to unsettled on March 11-13. 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
|Total spot count:||32||62||29|
|Sunspot number:||42||132||99||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||42||80||47||(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||46||54||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||(126.7)||12.7 (2A) / 39.4 (2B) / 55.8 (2C)||(61.6 projected, -2.0)||(12.6)|
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.