Last major update issued on October 14, 2013 at 05:20 UTC.
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The geomagnetic field was very quiet on October 13. Solar wind speed at SOHO ranged between 288 and 353 km/s. Solar wind speed is increasing early on Oct.14, most likely due to the arrival of a stream from CH590.
Solar flux measured at 20h UTC on 2.8 GHz was 129.3 (increasing 34.8 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 112.2. The Potsdam WDC planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 1.6). Three hour interval K indices: 10000011 (planetary), 10001200 (Boulder).
The background x-ray flux was at the class B4 level.
At the time of counting spots (see image time) spots were observed in 14 active regions in 2K resolution (SN: 237) and 10 active regions in 1K resolution (SN: 148) SDO images on the visible solar disk.
Region 11857 [S08W77] was quiet and stable.
Region 11860 [S29W35] reemerged with a penumbra spot.
Region 11861 [S09W18] was mostly unchanged. An M class flare is still possible.
Region 11863 [S19W48] developed slowly and quietly.
Region 11864 [S23E03] decayed slowly. Another M class flare is possible. C5+ flare: M1.7 at 00:43 UTC.
Region 11867 [N22W29] was quiet and stable.
New region 11868 [N18E49] rotated into view on October 11 and was numbered by SWPC 2 days later.
New region 11869 [N18E67] rotated into view on October 12 and got its NOAA number the next day.
Spotted regions not numbered by SWPC:
S2740 [N03W52] decayed slowly and quietly.
S2745 [N04W11] reemerged with penumbra spots.
New region S2753 [N17E77] rotated into view. The leading polarity area is close to the trailing spots of AR 11869.
October 11-12: No obviously Earth directed CMEs were observed in LASCO and
October 13: A partial halo CME was observed after an M1 flare in AR 11864 early in the day. There is a 20-30% chance the CME could reach Earth late on October 15 or on October 16.
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 (CH590) was in an Earth facing position on October 11-12.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is fair. Propagation on long distance northeast-southwest paths is poor to fair.
The geomagnetic field is expected to be quiet to active on October 14-15 due to effects from CH590. If the CME observed early on October 13 reaches Earth, unsettled and active intervals will be possible on October 16, otherwise quiet conditions are likely.
|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
|11865||2013.10.08||16||S22E06||0270||DKC||part of AR 11864|
|Total spot count:||45||97||48|
|Sunspot number:||125||237||148||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||88||137||88||(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):||75||83||81||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 (SIDC)||Smoothed sunspot number||Average ap
|2011.11||153.5 (cycle peak)||96.7 (cycle peak)||61.1 (+1.2)||5.55|
likely cycle 24 max
|2013.04||124.8||72.4||(56.2 projected, -1.3)||5.40|
|2013.05||131.4||78.7||(55.8 projected, -0.4)||9.73|
|2013.06||110.1||52.5||(56.0 projected, +0.2)||12.60|
|2013.07||115.5||57.0||(56.1 projected, +0.1)||9.47|
|2013.08||114.6||66.0||(55.9 projected, -0.2)||8.27|
|2013.09||102.6||36.9||(55.4 projected, -0.5)||5.23|
|2013.10||114.9 (1)||36.9 (2A) / 88.1 (2B) / 49.4 (2C)||(53.9 projected, -1.5)||(10.27)|
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 SIDC 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.