Last major update issued on February 23, 2014 at 05:40 UTC.
[Solar and geomagnetic data - last month (updated
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update February 1, 2014)] [Cycle 24 progress (last update February 1, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update February 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update February 1, 2014)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update February 1, 2014)]
[POES auroral activity level since October
2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated February 23, 2014]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]
The geomagnetic field was quiet to minor storm on February 22. Solar wind speed at SOHO ranged between 379 and 481 km/s, after 08h UTC under the influence of a high speed stream associated with CH604.
Solar flux at 20h UTC on 2.8 GHz was 163.2 (increasing 25.3 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 150.3. The Potsdam WDC planetary A index was 14 (STAR Ap - based on the mean of three hour interval ap indices: 14.4). Three hour interval K indices: 53332322 (planetary), 53232222 (Boulder).
The background x-ray flux is at the class C1 level.
At the time of counting spots (see image time) spots were observed in 13 active regions in 2K resolution (SN: 367) and 11 active regions in 1K resolution (SN: 233) SDO images on the visible solar disk.
Region 11981 [S07W07] decayed in the leading spot
section. The trailing penumbra displayed some fragmentation as well. The region was quiet.
Region 11982 [S11E06] developed slowly in the trailing spot section where a small magnetic delta structure appears to be forming. The region was mostly quiet. An M class flare is possible.
Region 11983 [S14W15] was quiet and stable.
Region 11984 [S19W07] decayed slowly and quietly.
Region 11986 [N13E35] developed slowly and quietly.
Region 11987 [S01E64] developed slowly and was quiet.
New region 11988 [S10E35] emerged on February 21 and was numbered by SWPC the next day as the region began to decay.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3127 [S23W45] reemerged with a penumbra spot.
S3135 [S31W38] was quiet and stable.
S3141 [S06E03] developed quickly and was the most active region on the visible disk. Minor M class flaring is possible. Apparently SWPC includes this region in AR 11982.
New region S3150 [S13E31] emerged early in the day with a penumbra spot.
New region S3151 [N09E79] rotated into view.
New region S3152 [N22W25] emerged during the latter half of the day with penumbra spots.
The only interesting flare of the day was a long duration C7.7 event peaking at 15:50 UTC from a source just behind the southeast limb.
February 20: A faint asymmetric full halo CME was observed after a C3
flare in AR 11982 early in the day. Weak effects from this CME could reach Earth
on February 23.
February 21-22: 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 trans equatorial coronal hole (CH604) was in an Earth facing position on February 20-21. A negative polarity trans equatorial coronal hole will likely rotate into an Earth facing position on February 24-25.
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 fair.
The geomagnetic field is expected to be quiet to unsettled on February 23 due to effects from CH604 and quiet on February 24-25.
|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: 0-20% 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.
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:||99||237||123|
|Sunspot number:||179||367||233||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||122||270||156||(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):||107||128||128||k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for STAR SDO 2K, k = 0.55 for STAR SDO 1K|
|Month||Average solar flux||International sunspot number
|Smoothed sunspot number||Average ap
|2011.11||153.5||96.7 (cycle peak)||61.1 (+1.2)||5.55|
|2013.08||114.6||118.3||66.0||(69.0 projected, +3.5)||8.27|
|2013.09||102.6||103.7||36.9||(73.0 projected, +4.0)||5.23|
|2013.10||132.1||131.2||85.6||(74.0 projected, +1.0)||7.71|
|2013.11||148.3||145.1||77.6||(72.9 projected, -1.1)||5.68|
|2013.12||147.7||143.1||90.3||(71.8 projected, -1.1)||4.68|
|152.4||82.0||(71.0 projected, -0.8)||5.44|
|2014.02||169.4 (1)||130.0 (2A) / 165.4 (2B) / 108.1 (2C)||(71.2 projected, +0.2)||(11.1)|
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.