Last major update issued on February 27, 2014 at 05:50 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 on February 26. Solar wind speed at SOHO ranged between 334 and 364 km/s.
Solar flux at 20h UTC on 2.8 GHz was 178.2 (increasing 17.7 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 152.5. The Potsdam WDC planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 1.8). Three hour interval K indices: 20000001 (planetary), 20002211 (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 21 active regions in 2K resolution (SN: 448) and 19 active regions in 1K resolution (SN: 310) SDO images on the visible solar disk.
Region 11981 [S08W60] decayed losing spots and
Region 11982 [S11W48] decayed slowly and lost the magnetic delta structure after the M class flare. C5+ flare: M1.1/1N at 15:01 UTC.
Region 11983 [S14W63] developed slowly and quietly.
Region 11984 [S17W62] matured quickly and was quiet.
Region 11986 [N13W13] decayed slowly and quietly.
Region 11987 [S02E09] gained a few spots and was quiet.
Region 11989 [N08E26] decayed slowly and quietly.
Region 11990 [S12E52] was mostly quiet. With a strong magnetic delta structure inside the single large spot another major flare is possible.
New region 11991 [S25E67] rotated into view on February 25 and was numbered the next day by SWPC.
New region 11992 [S20E21] emerged on February 25 and received its NOAA number the following day.
New region 11993 [N17E58] emerged on February 25 and developed further on February 26 when it was numbered by SPWC.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3141 [S06W49] decayed significantly and was quiet.
S3150 [S16W23] reemerged with penumbra spots.
S3155 [S06E12] was quiet and stable.
S3156 [N05E34] was quiet and stable.
S3163 [S11E33] was quiet and stable.
S3164 [N18E47] has tiny penumbra spots in an old plage area.
New region S3167 [N09W61] emerged early in the day, then decayed slowly during the latter hald of the day.
New region S3168 [S09W23] emerged quickly and could generate C flares.
New region S3169 [N11E45] emerged with penumbra spots.
New region S3170 [S23W31] emerged with a penumbra spot.
February 24, 26: 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 will likely reach 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 poor. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet to minor storm on February 27-28 due to CME and coronal hole effects. Quiet to unsettled is likely on March 1.
|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:||97||238||120|
|Sunspot number:||197||448||310||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||140||297||179||(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):||118||157||171||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||170.1 (1)||156.5 (2A) / 168.6 (2B) / 114.9 (2C)||(71.2 projected, +0.2)||(10.5)|
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.