Last major update issued on March 14, 2014 at 05:35 UTC.
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[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]
The geomagnetic field was quiet to active on March 13. Solar wind speed at SOHO ranged between 304 and 494 km/s under the influence of a stream from CH607.
Solar flux at 20h UTC on 2.8 GHz was 147.7 (decreasing 18.9 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 153.7. The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.3). Three hour interval K indices: 43312121 (planetary), 43312211 (Boulder).
The background x-ray flux is at the class B8 level.
At the time of counting spots (see image time) spots were observed in 13 active regions in 2K resolution (SN: 272) and 13 active regions in 1K resolution (SN: 206) SDO images on the visible solar disk.
Region 11998 [S09W39] decayed slowly and quietly.
Region 12002 [S19W03] was mostly quiet and stable. The region has a magnetic delta structure and could produce an M class flare.
Region 12003 [N06W50] decayed slowly and quietly.
Region 12004 [S11E22] developed slowly and quietly.
Region 12005 [N12E58] was quiet and stable.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3211 [S09W61] decayed slowly and quietly.
S3212 [N17W38] was quiet and stable.
New region S3214 [N10E78] rotated into view. Although likely a region on its own, there is a chance the spots could be the trailing section of AR 12005. This will be easier to determine when the spots rotate into better view.
New region S3215 [N11E39] emerged with penumbra spots.
New region S3216 [S01E22] emerged with penumbra spots and the polarity layout of a northern hemisphere region.
New region S3217 [S26E18] emerged with a penumbra spot.
New region S3218 [N11W48] emerged quickly during the latter half of the day just north of AR 12003. C flares are possible, further development could cause larger flares.
AR 11996 behind the northwest limb produced the only noteworthy flare of the day, an M1.2 flare at 19:19 UTC.
March 11-13: 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 small southern hemisphere coronal hole (CH607) was in an Earth facing position on March 9.
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 to fair.
The geomagnetic field is expected to be quiet to unsettled on March 14 and quiet on March 15-16.
|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
|3||N16W90||0060||DAO||rotated out of view|
real location: S14W83
SWPC has adopted the spots of AR S3210
real location: S11W50
SWPC has adopted the spots of AR S3211
|S3214||2014.03.13||2||2||N10E78||0050||HSX||possibly the trailing spots of AR 12005|
|Total spot count:||60||142||76|
|Sunspot number:||130||272||206||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||96||178||112||(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):||78||95||113||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 ap
|2013.09||102.6||103.7||36.9||(72.8 projected, +3.8)||5.23|
|2013.10||132.1||131.2||85.6||(73.8 projected, +1.0)||7.71|
|2013.11||148.3||145.1||77.6||(72.7 projected, -1.1)||5.68|
|2013.12||147.7||143.1||90.3||(71.6 projected, -1.1)||4.68|
|2014.01||157.4||152.4||82.0||(71.6 projected, 0.0)||5.44|
|166.3||102.8 (cycle peak)||(70.9 projected, -0.7)||10.70|
|2014.03||153.1 (1)||63.7 (2A) / 151.9 (2B) / 118.1 (2C)||(71.0 projected, +0.1)||(4.7)|
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.