Last major update issued on September 19, 2014 at 04:25 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)]
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[New: Noon SDO count 1K 4K (large file)]
[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 18. Solar wind speed at SOHO ranged between 320 and 376 km/s. A disturbance began after 17h UTC and is causing active conditions early on September 19.
Solar flux at 20h UTC on 2.8 GHz was 120 (decreasing 6.4 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 134.1. The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.1). Three hour interval K indices: 21101123 (planetary), 21112223 (Boulder).
The background x-ray flux is at the class B6 level.
At the time of counting spots (see image time), spots were observed in 9 active regions using 2K resolution (SN: 158) and 7 active regions using 1K resolution (SN: 101) SDO images on the visible solar disk.
Region 12164 [S14W64] decayed slowly, a weak
magnetic delta structure is still present in the largest penumbra.
Region 12166 [N12W10] decayed slowly and was quiet.
Region 12167 [N07E07] reemerged with penumbra spots.
Region 12168 [S22E32] was mostly quiet and stable.
Region 12169 [N04E54] was the most active region on the visible disk producing C flares and a minor M class flare. Magnetically the region has a simple structure.
Region 12170 [N10E54] was quiet and stable.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3821 [S12E04] was quiet and stable.
New region S3830 [S10E80] rotated into view and could produce C flares.
New region S3831 [S23E62] emerged with one spot.
|Magnitude||Peak time (UTC)||Location||AR||Comment|
September 16-18: 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]
An extension of a large southern hemisphere coronal hole was in an Earth facing position on September 15.
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 active on September 19 and quiet on September 20-21.
|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: 0-30% 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.
|Active region||Date numbered
|Spot count||Location at midnight||Area||Classification||SDO / HMI 4K continuum
image with magnetic polarity overlay
|Total spot count:||25||68||31|
|Sunspot number:||75||158||101||(total spot count + 10 * number of spotted regions)|
|Relative sunspot number (Wolf number):||45||55||56||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||143.2 (1)||79.4 (2A) / 132.3 (2B) / 84.9 (2C)||(65.9 projected, -4.2)||(8.1)|
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.