Last major update issued on February 1, 2014 at 05:20 UTC.
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[Solar cycles 1-20]
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[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]
The geomagnetic field was very quiet on January 31. Solar wind speed at SOHO ranged between 277 and 368 km/s.
Solar flux at 20h UTC on 2.8 GHz was 165.7 (decreasing 37.6 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 147.0. The Potsdam WDC planetary A index was 1 (STAR Ap - based on the mean of three hour interval ap indices: 0.9). Three hour interval K indices: 00010000 (planetary), 10011211 (Boulder).
The background x-ray flux is at the class C1 level.
At the time of counting spots (see image time) spots were observed in 8 active regions in 2K resolution (SN: 245) and 4 active regions in 1K resolution (SN: 130) SDO images on the visible solar disk.
Region 11963 [S10W69] was quiet and stable.
Region 11967 [S12E31] was surprisingly quiet taking into consideration its complexity. Some development was observed in the northern central section. The region has 3 magnetic delta structures and is capable of producing M and X class flares. C5+ flare: C6.3 at 00:18 UTC on Feb.1 (the flare began at 23:59 UTC).
Region 11968 [N10E29] gained spots and has polarity intermixing. C5+ flare: M1.1 at 15:42 UTC. LASCO imagery indicates that this event was associated with a halo CME.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3071 [S10W20] developed slowly and quietly.
S3073 [N19E32] gained leading penumbra spots.
S3075 [S12E56] decayed slowly and quietly.
S3077 [N13E07] was first observed with a penumbra spot at noon at January 30, lost the spot by the end of the day, then reemerged on Jan.31.
New region S3079 [S13E45] emerged with penumbra spots.
January 29: A halo CME was observed after a filament eruption in the
southwest quadrant. While the core of the CME will not reach Earth, there's a
chance a weak solar wind shock will be observed on February 1.
January 30: A halo CME was observed after an M1 event in AR 11967 at 08:11 UTC. The CME was faint over the west limbs and the north pole. A much larger CME was observed after the M6 flare in AR 11967 at 16:11 UTC. This CME could reach Earth on February 2.
January 31: Although imagery is incomplete from the hours after the M1 event in AR 11968, LASCO C3 images indicate that there was a halo CME associated. The CME could reach Earth on February 3.
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 recurrent trans equatorial coronal hole (CH602) will likely rotate into an Earth facing position on February 5-6.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle latitudes is fair to good. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet on February 1 with a chance of unsettled intervals due to weak CME effects. On February 2 quiet to active conditions are possible due to effects from the largest CME observed on January 30. On February 3 we can expect quiet to unsettled conditions.
|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.
|Active region||Date numbered
|Spot count||Location at midnight||Area||Classification||SDO / HMI 4K continuum
image with magnetic polarity overlay
SWPC location on Jan.27: S06W25
SWPC location on Jan.27: S14W28
SWPC location on Jan.28: S14W24
SWPC has moved AR 11965 to this location
|Total spot count:||67||165||90|
|Sunspot number:||87||245||130||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||82||183||108||(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):||52||86||72||k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for STAR SDO 2K, k = 0.55 for STAR SDO 1K|
|Month||Average measured solar flux||International sunspot number (SILSO)||Smoothed sunspot number||Average ap
|2011.11||153.5||96.7 (cycle peak)||61.1 (+1.2)||5.55|
|2013.08||114.6||66.0||(67.8 projected, +2.3)||8.27|
|2013.09||102.6||36.9||(69.6 projected, +1.8)||5.23|
|2013.10||132.1||85.6||(69.3 projected, -0.3)||7.71|
|2013.11||148.3||77.6||(67.5 projected, -1.8)||5.68|
|2013.12||147.7||90.3||(66.7 projected, -0.8)||4.68|
|2014.01||157.4 (cycle peak)||82.0||(66.9 projected, +0.2)||5.4|
|2014.02||(1)||0.0 (2A/2B) / 103.1 (2C)||(65.9 projected, -1.0)||()|
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 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.