Last major update issued on February 21, 2014 at 06:25 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 1, 2014]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]
The geomagnetic field was quiet to major storm on February 20. Solar wind speed at SOHO ranged between 460 and 713 km/s. A solar wind shock was observed at SOHO at 03:14 UTC, the arrival of the CME observed on February 18.
Solar flux at 20h UTC on 2.8 GHz was 156.4 (increasing 20.9 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 149.7. The Potsdam WDC planetary A index was 36 (STAR Ap - based on the mean of three hour interval ap indices: 36.0). Three hour interval K indices: 26654433 (planetary), 16566322 (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 11 active regions in 2K resolution (SN: 274) and 10 active regions in 1K resolution (SN: 183) SDO images on the visible solar disk.
Region 11976 [S14W82] decayed further losing
penumbral area. C5+ flare: long duration
M3.0 event peaking at 07:56 UTC. This event was associated with a minor proton
event and a CME. The CME does not appear to have Earth directed extensions.
Region 11977 [S09W58] was quiet and stable.
Region 11981 [S07E20] developed slowly and quietly. C and minor M class flares are possible.
Region 11982 [S11E32] gained spots, particularly in the central section. There's polarity intermixing and a chance of a minor M class flare. The region produced a C3.3 flare at 03:35 UTC. A faint asymmetric halo CME appears to be associated to the event.
Region 11983 [S12E11] was quiet and stable.
Region 11984 [S16E18] was quiet and stable.
Region 11985 [N06W58] decayed slowly and quietly.
New region 11986 [N13E62] rotated into view early on February 19 and was numbered the next day by SWPC.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3141 [S07E32] was quiet and stable.
New region S3144 [S16E02] emerged early in the day, then decayed during the latter half of the day.
New region S3145 [S05W03] was another of a number of small groups to emerge during the first half of the day and then decay.
February 18: An asymmetric full halo CME was observed after a filament eruption in the
southeast quadrant. The CME reached Earth early on February 20.
February 19: A faint partial halo CME was observed after 16h and was likely associated with a filament eruption in the southern hemisphere. An extension of the CME could reach Earth on February 22.
February 20: A faint asymmetric full halo CME was observed after a C3 flare in AR 11982 early in the day. Weak effects from this CME could reach Earth on February 23.
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 trans equatorial coronal hole (CH604) rotated into an Earth facing position on February 20-21.
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 February 21-22 due to weak CME effects. A high speed stream from CH604 could cause unsettled and active intervals on February 23-24.
|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:||70||164||83|
|Sunspot number:||140||274||183||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||95||191||110||(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):||84||96||101||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)||118.1 (2A) / 165.4 (2B) / 107.4 (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.