Last major update issued on February 1, 2015 at 05:20 UTC.
[Solar and geomagnetic data - last month (updated
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update February 1, 2015)] [Cycle 24 progress (last update February 1, 2015) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update February 1, 2015)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update February 1, 2015)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update January 3, 2015)]
[Noon SDO sunspot count 1K Reference: 4K (large file) (updated daily)]
[POES auroral activity level October
2009 - December 2012]
[Solar polar fields vs solar cycles - updated January 25, 2015]
[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]
The geomagnetic field was quiet to unsettled on January 31. Solar wind speed at SOHO ranged between 379 and 421 km/s. A disturbance began late in the day, probably related to a recurrent co-rotating interaction region.
Solar flux at 20h UTC on 2.8 GHz was 153.5 (increasing 3.8 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 148.1. The Potsdam WDC planetary A index was 7 (STAR Ap - based on the mean of three hour interval ap indices: 6.8). Three hour interval K indices: 12111223 (planetary), 12112223 (Boulder).
The background x-ray flux is at the class B5 level.
At the time of counting spots (see image time), spots were observed in 10 active regions using 2K resolution (SN: 280) and 10 active regions using 1K resolution (SN: 190) SDO images on the visible solar disk.
Region 12268 [S09W49] decayed quickly, particularly
in the trailing polarity section where only one of the spots had umbra at the
end of the day.
Region 12271 [N18W70] decayed slowly and quietly.
Region 12272 [N12W08] decayed slowly and quietly.
Region 12273 [S03W68] decayed further and could soon become spotless.
Region 12275 [S17W80] decayed further and was quiet.
Region 12276 [S08W17] decayed and could soon become spotless.
Region 12277 [N08E36] lost spots and penumbral area in the intermediate spot section. A magnetic delta formed in a leading penumbra and the region could produce an M class flare.
Region 12278 [S08W00] was quiet and stable.
Spotted regions not numbered (or interpreted differently) by SWPC:
S4186 [S10E21] was quiet and stable.
New region S4189 [S18W31] emerged with a few penumbra spots.
C2+ flares (GOES):
|Magnitude||Peak time (UTC)||Location||AR||Comment|
January 29-31: No obviously Earth directed CMEs were observed in LASCO imagery.
[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]
An extension of the southern polar coronal hole could be associated with a co-rotating interaction region transiting the central meridian on January 29-30.
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 1-3 with a chance of active conditions on February 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: 0-30% probability, Yellow: 30-70% probability, Red: 70-100% 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:||73||180||90|
|Sunspot number:||153||280||190||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||111||208||118||(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):||92||98||105||k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for MSN 2K, k = 0.55 for MSN 1K (MSN=Magnetic Sunspot Number)|
|Month||Average solar flux||International sunspot number
|Smoothed sunspot number||Average ap
|166.3||102.3 (cycle peak)||78.4 (+1.1)||10.70|
(likely solar max)
|2014.08||124.7||127.9||74.7||(76.2 projected, -2.4)||7.71|
|2014.09||146.6||148.1||87.6||(73.0 projected, -3.2)||9.78|
|2014.10||153.4||152.9||60.6||(70.5 projected, -2.5)||8.96|
|2014.11||154.8||151.4||70.1||(68.8 projected, -1.7)||9.33|
|2014.12||158.7||153.8||78.0||(67.7 projected, -1.1)||11.24|
|2015.01||141.9||137.3||67.0||(66.5 projected, -1.2)||8.9|
|2015.02||(1)||101.3 (2A/2B) / 77.3 (2C)||(64.9 projected, -1.6)||()|
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.