Last major update issued on September 12, 2014 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 September 1, 2014)] [Cycle 24 progress (last update September 1, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update September 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update September 1, 2014)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update September 6, 2014)]
[POES auroral activity level October
2009 - December 2012]
[Solar polar fields vs solar cycles - updated September 6, 2014]
[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]
The geomagnetic field was quiet to unsettled on September 11. Solar wind speed at SOHO ranged between 325 and 446 km/s. A weak to moderate solar wind shock was observed at SOHO at 23:02 UTC, the arrival of the September 9 CME. While the interplanetary magnetic field initially saw some moderately southward swings, the IMF has been mostly weakly northwards since 03h UTC on Sept.12.
Solar flux at 20h UTC on 2.8 GHz was 151 (increasing 37.9 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 133.0. The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices:9.8). Three hour interval K indices: 33221113 (planetary), 33444313 (Boulder).
The background x-ray flux is at the class B7 level.
At the time of counting spots (see image time), spots were observed in 12 active regions using 2K resolution (SN: 272) and 11 active regions using 1K resolution (SN: 187) SDO images on the visible solar disk.
Region 12155 [S19W31] decayed slowly and quietly.
Region 12157 [S14W19] decayed significantly and lost the magnetic delta structure. C and minor M class flaring is possible.
Region 12158 [N16W12] decayed with the large penumbra splitting in the northern section. The northernmost penumbra developed a weak magnetic delta structure. An M class flare is possible.
Region 12159 [S21W07] decayed slowly and quietly.
Region 12161 [S12W80] decayed slowly and quietly.
Region 12163 [S16E09] was mostly quiet and stable.
New region 12164 [S13E27] emerged on September 9 and was numbered by SWPC 2 days later.
New region 12165 [S08E64] rotated into view on September 10 with SWPC numbering the region the next day.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3808 [S13W62] reemerged with a penumbra spot.
S3811 [S24E08] was quiet and stable.
New region S3816 [S10E38] emerged with penumbra spots.
New region S3817 [N11E44] emerged with penumbra spots.
An interesting active region just behind the northeast limb produced most of the flares recorded during the day.
|Magnitude||Peak time (UTC)||Location||AR||Comment|
September 9: An asymmetric full halo CME was observed after the M4.5 flare in AR 12158
late on Sept.8.
September 10: A large and wide Earth directed asymmetric full halo CME was observed after the X1 event in AR 12158.
September 11: No obviously Earth directed CMEs were observed in LASCO and STEREO 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]
No obvious coronal holes are currently in or near Earth facing positions.
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 major storm on September 12-13 due to CME effects, isolated severe storm intervals are possible when the Sept.10 CME arrives. Quiet to unsettled conditions are likely on September 14.
|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:||74||152||77|
|Sunspot number:||164||272||187||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||107||180||105||(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):||98||95||103||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|
|2014.03||149.9||148.5||91.9||(80.3 projected, +1.9)||4.88|
|2014.04||143.9||144.8||84.7||(81.0 projected, +0.7)||7.88|
|2014.05||129.7||132.9||75.2||(79.2 projected, -1.8)||5.75|
|2014.06||122.0||125.8||71.0||(76.6 projected, -2.6)||6.72|
|2014.07||137.4||141.8||72.5||(73.6 projected, -3.0)||4.50|
|2014.08||124.7||127.9||74.7||(70.1 projected, -3.5)||7.71|
|2014.09||148.5 (1)||51.1 (2A) / 139.3 (2B) / 81.7 (2C)||(65.9 projected, -4.2)||(7.0)|
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 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.