Last major update issued on March 8, 2014 at 08:10 UTC.
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[Solar cycles 23-24 (last update March 1, 2014)] [Cycle 24 progress (last update March 1, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update March 1, 2014)]
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[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]
The geomagnetic field was very quiet on March 7. Solar wind speed at SOHO ranged between 348 and 461 km/s.
Solar flux at 20h UTC on 2.8 GHz was 148.2 (decreasing 23.6 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 154.7. The Potsdam WDC planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 1.9). Three hour interval K indices: 00001110 (planetary), 10102212 (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 14 active regions in 2K resolution (SN: 260) and 11 active regions in 1K resolution (SN: 181) SDO images on the visible solar disk.
Region 11990 [S12W67] was quiet and stable. A small
negative polarity umbra is very close to merging with the single large penumbra.
If this occurs the region would again have a magnetic delta structure.
Region 11991 [S26W46] displayed severe fragmentation of what was the single remaining large penumbra.
Region 11993 [N17W60] decayed further and could soon become spotless.
Region 11995 [S17W77] decayed slowly and quietly.
Region 11996 [N14W10] decayed slowly and quietly.
Region 11998 [S10E41] was quiet and stable.
Region 11999 [S16W05] decayed quietly.
Region 12000 [S11E28] gained some spots but lost umbra on one polarity.
Region 12001 [N19W50] was quiet and stable.
Spotted regions not numbered (or interpreted differently) by SWPC:
New region S3196 [N10E18] emerged with penumbra spots.
New region S3197 [N09E07] emerged with penumbra spots.
New region S3198 [S20W14] emerged with a penumbra spot.
New region S3199 [S27E18] emerged with a penumbra spot.
New region S3200 [S19E78] rotated into view. The region was the source of the most energetic event of the day, a C3.5 flare which started right before midnight and peaked at 00:07 UTC on March 8.
March 5-7: 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 northern hemisphere coronal hole (CH606) may have been in an Earth facing position on March 5-6, the coronal hole may be too far to the north to become geoeffective. A small southern hemisphere coronal hole (CH607) will likely rotate into 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 fair. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet with a chance of unsettled intervals on March 8-9 due to possible effects from CH606. Quiet conditions are likely on March 10-11 with weak coronal hole effects possible on March 12-13.
|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
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
|Total spot count:||71||120||71|
|Sunspot number:||161||260||181||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||106||150||101||(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):||97||91||100||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||155.9 (1)||39.0 (2A) / 172.7 (2B) / 124.0 (2C)||(71.0 projected, +0.1)||(4.4)|
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.