Last major update issued on February 13, 2014 at 05:30 UTC.
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[Solar cycles 23-24 (last update February 1, 2014)] [Cycle 24 progress (last update February 1, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update February 1, 2014)]
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[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]
The geomagnetic field was quiet to unsettled on February 12. Solar wind speed at SOHO ranged between 347 and 498 km/s.
Solar flux at 20h UTC on 2.8 GHz was 160.1 (increasing 39.1 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 149.8. The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.4). Three hour interval K indices: 33111111 (planetary), 33112321 (Boulder).
The background x-ray flux is at the class C2 level.
At the time of counting spots (see image time) spots were observed in 14 active regions in 2K resolution (SN: 366) and 13 active regions in 1K resolution (SN: 257) SDO images on the visible solar disk.
Region 11971 [S12W58] was mostly quiet and stable.
C5+ flares: C7.9 at 12:34 UTC.
Region 11973 [N05W32] decayed slowly and was quiet.
Region 11974 [S12W19] decayed slowly and quietly. SWPC has not managed to split off AR S3098 and are counting these two groups as one.
Region 11975 [S15W83] decayed slowly and quietly.
Region 11976 [S15E23] decayed slowly and quietly.
Region 11977 [S10E51] developed slowly and could produce C and minor M class flares.
Region 11978 [N05W53] gained spots and lost penumbral area.
New region 11979 [N14W41] emerged on February 11 and was numbered by SWPC the next day as the region was decaying.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3098 [S12W10] developed further and has a very messy magnetic layout with lots of polarity intermixing and several magnetic delta structures and the leading an central sections. An X class flare is possible. C5+ flares: M3.7/2N at 04:25, M1.0 at 06:10 (not reported by SWPC), M2.3/2F at 06:58 (a slow symmetric full halo CME was observed after this event), M2.1 at 15:51, C5.9 at at 21:30 UTC.
S3102 [S19W22] lost the leader spot and gained trailing penumbra spots.
S3105 [S14E34] was quiet and stable.
New region S3118 [N07W48] emerged to the northeast of AR 11978 with a few spots.
New region S3120 [S25W04] emerged with penumbra spots.
New region S3121 [S21W42] emerged with penumbra spots.
February 10: No obviously Earth directed CMEs were observed in LASCO and
February 11: A partial halo CME was observed after 11h UTC following a filament eruption near AR 11978 in the northwest quadrant. It is uncertain if the CME has any Earth directed components.
February 12: A slow symmetric full halo CME was observed after an M2 flare in AR S3098. The CME could reach Earth on February 15.
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
No obvious coronal holes are currently in or near Earth facing positions.
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 on February 13-14. Quiet to active conditions with a chance of minor storm intervals is possible on February 15 due to CME effects.
|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
SWPC has this as part of AR 11974
|S3105||2014.02.09||4||3||S14E34||0190||CSO||SWPC has this as part of AR 11976|
|Total spot count:||107||226||127|
|Sunspot number:||187||366||257||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||157||277||178||(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):||112||128||141||k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for STAR SDO 2K, k = 0.55 for STAR SDO 1K|
|Month||Average solar flux||International sunspot number
|Smoothed sunspot number||Average ap
|2011.11||153.5||96.7 (cycle peak)||61.1 (+1.2)||5.55|
|2013.08||114.6||118.3||66.0||(69.0 projected, +3.5)||8.27|
|2013.09||102.6||103.7||36.9||(73.0 projected, +4.0)||5.23|
|2013.10||132.1||131.2||85.6||(74.0 projected, +1.0)||7.71|
|2013.11||148.3||145.1||77.6||(72.9 projected, -1.1)||5.68|
|2013.12||147.7||143.1||90.3||(71.8 projected, -1.1)||4.68|
|152.4||82.0||(71.0 projected, -0.8)||5.44|
|2014.02||177.4 (1)||83.6 (2A) / 180.2 (2B) / 107.9 (2C)||(71.2 projected, +0.2)||(7.9)|
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 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.