Last major update issued on October 20, 2012 at 05:40 UTC.
[Solar and geomagnetic data - last month (updated
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 21-24 (last update October 3, 2012)] [Cycle 24 progress (last update October 1, 2012) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update October 3, 2012)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update October 3, 2012)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update October 1, 2012)]
[POES auroral activity level since October
2009 - updated October 7, 2012]
[Solar polar fields vs solar cycles - updated June 27, 2011]
The geomagnetic field was quiet to unsettled on October 19. Solar wind speed at SOHO ranged between 372 and 543 km/s, slowly decreasing all day.
Solar flux measured at 20h UTC on 2.8 GHz was 141.4 (increasing 16.9 over the last solar rotation). The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 4.6). Three hour interval K indices: 31111010 (planetary), 20002220 (Boulder).
The background x-ray flux was at the class B5 level.
At midnight UTC the visible solar disk had 12 spotted active regions (in 2K resolution SDO images).
Region 11589 [N12W59] decayed slowly and produced a few C flares.
Region 11591 [N07W21] decayed slowly and quietly.
Region 11592 [N22W44] was quiet and stable.
Region 11593 [N16E22] developed slowly and quietly and has minor polarity intermixing.
Region 11594 [S28E08] was quiet and stable.
Region 11596 [N06E60] was mostly quiet but has M class flaring potential.
Region 11597 [S22W43] developed slowly and was mostly quiet.
Spotted regions not numbered by NOAA/SWPC:
S1993 [N20W11] was quiet and stable.
S1997 [N06E25] gained trailing polarity spots.
New region S1999 [N07E33] emerged with a tiny spot.
New region S2000 [N13E12] emerged with tiny spots.
New region S2001 [S18E24] emerged with tiny spots.
October 17-19: 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
A northern hemisphere coronal hole (CH542) was in an Earth facing position on October 17-18.
The above coronal hole map is based on a method where coronal holes are detected automatically. While the method may need some fine tuning, it has significant advantages over detecting coronal holes manually. The main improvement is the ability to detect coronal holes at and just beyond the solar limbs. Early results using this method for SDO images over a span of several weeks indicate a good match between coronal holes observed over the visible disk and their extent and position at the east and west limbs. Note that the polar coronal holes are easily detected using this method, the extent and intensity of both CHs are consistent with other data sources.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and 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 October 20 becoming quiet to unsettled on October 21 due to effects from CH542.
|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 higher resolution image) 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 (blue-green) is positive.
|Active region||Date numbered
|Spot count||Location at midnight||Area||Classification||SDO / HMI 4K continuum
image with magnetic polarity overlay
|1||S12W93||0060||HSX||rotated out of view|
|Total spot count:||30||105||38|
|Sunspot number:||110||225||118||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||63||130||63||(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):||66||79||65||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
possible cycle 24 max
|2012.04||113.0||55.2||(64.7 projected, -2.1)||10.10|
|2012.05||121.5||69.0||(61.8 projected, -2.9)||7.06|
|2012.06||119.6||64.5||(59.9 projected, -1.9)||10.08|
|2012.07||133.9||66.5||(60.0 projected, +0.1)||13.90|
|2012.08||115.4||63.1||(62.0 projected, +2.0)||7.96|
|2012.09||122.9||61.5||(63.6 projected, +1.6)||8.07|
|2012.10||119.8 (1)||46.7 (2A) / 76.2 (2B) / 57.9 (2C)||(63.5 projected, -0.1)||(15.91)|
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 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.