Last major update issued on February 20, 2014 at 05:25 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 19. Solar wind speed at SOHO ranged between 353 and 548 km/s. A moderate solar wind shock was observed at SOHO at 02:58 UTC. The interplanetary magnetic field was at times moderately to strongly southwards which caused minor to major geomagnetic storming. A stronger solar wind shock was observed at SOHO at 03:14 UTC on February 20, the arrival of the CME observed on February 18. Solar wind speed increased abruptly to 650 km/s.
Solar flux at 20h UTC on 2.8 GHz was 157.7 (increasing 21.4 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 149.5. The Potsdam WDC planetary A index was 46 (STAR Ap - based on the mean of three hour interval ap indices: 45.5). Three hour interval K indices: 56656323 (planetary), 46555322 (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 12 active regions in 2K resolution (SN: 279) and 11 active regions in 1K resolution (SN: 195) SDO images on the visible solar disk.
Region 11976 [S14W69] decayed retaining only a few
positive polarity spots.
Region 11977 [S10W42] decayed retaining only rudimentary penumbra on the few remaining umbrae.
Region 11981 [S07E34] developed slowly and quietly.
Region 11982 [S11E47] matured with polarity separation increasing. A few low level C flares were observed.
Region 11983 [S11E25] decayed slowly and quietly.
Region 11984 [S16E32] was quiet and stable.
New region 11985 [N07W46] emerged on February 18 and was numbered by SWPC the next day.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3127 [S23W13] reemerged with penumbra spots.
S3135 [S29E05] was quiet and stable.
S3137 [S20E14] reemerged with a few penumbra spots.
New region S3140 [N13E76] rotated into view.
New region S3141 [S06E46] was split off from AR 11982.
A filament eruption in the southern hemisphere began at 15h UTC. STEREO and LASCO imagery indicate that a faint partial halo CME was launched. There is a chance an extension of the CME could reach Earth on February 22.
February 17: A small CME was observed in STEREO imagery after a C6 event
in AR 11977 near center disk..
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.
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) could rotate 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 very poor. Propagation on long distance northeast-southwest paths is fair.
The geomagnetic field is expected to be quiet to major storm on February 20-21 due to CME effects and quiet to unsettled on February 22. 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:||63||159||85|
|Sunspot number:||123||279||195||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||91||199||125||(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):||74||98||107||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||171.1 (1)||113.1 (2A) / 166.7 (2B) / 108.2 (2C)||(71.2 projected, +0.2)||(9.5)|
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.