Last major update issued on February 28, 2014 at 06:10 UTC.
[Solar and geomagnetic data - last month (updated
[Solar wind and electron fluence charts (updated daily)]
[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)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update February 1, 2014)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update February 1, 2014)]
[POES auroral activity level since October
2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated February 23, 2014]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]
The geomagnetic field was quiet to minor storm on February 27. Solar wind speed at SOHO ranged between 328 and 439 km/s. A solar wind shock associated with the February 25 halo CME was observed at SOHO at 16:17 UTC.
Solar flux at 20h UTC on 2.8 GHz was 175.7 (increasing 10.0 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 153.0. The Potsdam WDC planetary A index was 18 (STAR Ap - based on the mean of three hour interval ap indices: 17.8). Three hour interval K indices: 11012355 (planetary), 11013554 (Boulder).
The background x-ray flux is at the class B9 level.
At the time of counting spots (see image time) spots were observed in 20 active regions in 2K resolution (SN: 401) and 18 active regions in 1K resolution (SN: 296) SDO images on the visible solar disk.
Region 11981 [S07W69] decayed quickly leaving only trailing polarity
Region 11982 [S11W62] decayed quickly losing all leading polarity umbrae.
Region 11983 [S15W78] decayed slowly and quietly.
Region 11984 [S18W78] decayed slowly and quietly.
Region 11986 [N13W28] decayed slowly and lost all umbrae. There are still many penumbra spots.
Region 11987 [S02W05] was mostly quiet and stable.
Region 11989 [N08E10] decayed and lost all umbrae, the are still a number of penumbra spots remaining.
Region 11990 [S13E38] was mostly quiet. New spots emerged in the southwestern part of the region, this may be a new region. The large penumbra still has magnetic delta structures and could be the origin of another major flare.
Region 11991 [S24E53] developed in the leading spot section and has polarity intermixing. The region was the most active one on the visible disk during the day. C5+ flares: C5.7 at 10:45, C6.8 at 12:30.
Region 11992 [S20E08] was quiet and stable.
Region 11993 [N16E46] is developing slowly and has polarity intermixing.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3141 [S07W63] decayed significantly and was quiet.
S3150 [S15W30] decayed slowly and quietly.
S3155 [S06W01] developed slowly. SWPC sems to be counting this region and AR 11987 as one, this despite that AR 11987 is a northern hemisphere region which has moved just south of the equator and AR S3155 is a southern hemisphere group.
S3156 [N05E19] was quiet and stable.
S3163 [S11E22] was quiet and stable.
S3164 [N21E32] was quiet and stable.
S3168 [S09W38] developed further and could produce C flares. SWPC decided to reuse AR 11988 for the these spots.
S3169 [N12E28] was quiet and stable.
New region S3171 [N01W29] emerged with penumbra spots.
February 26-27: No obviously Earth directed CMEs were observed in LASCO and
February 25: An asymmetric full halo CME was observed after the X4 flare in AR 11990. The CME reached Earth on February 27.
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 negative polarity trans equatorial coronal hole (CH605) was in an Earth facing position on February 24-25.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle latitudes is very poor. Propagation on long distance northeast-southwest paths is poor to fair.
The geomagnetic field is expected to be quiet to active on February 28 due to CME and coronal hole effects. Quiet to unsettled is likely on March 1-2.
|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: 0-20% 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 adopted the spots of AR S3168
|Total spot count:||117||201||116|
|Sunspot number:||227||401||296||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||176||252||167||(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):||136||140||163||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||170.3 (1)||164.6 (2A) / 170.7 (2B) / 117.5 (2C)||(71.2 projected, +0.2)||(10.8)|
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.