Last major update issued on March 1, 2014 at 07:15 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 active on February 28. Solar wind speed at SOHO ranged between 334 and 450 km/s under the influence of CME effects.
Solar flux at 20h UTC on 2.8 GHz was 170.6 (decreasing 6.0 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 153.5. The Potsdam WDC planetary A index was 12 (STAR Ap - based on the mean of three hour interval ap indices: 11.9). Three hour interval K indices: 43331211 (planetary), 32331322 (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 17 active regions in 2K resolution (SN: 348) and 16 active regions in 1K resolution (SN: 258) SDO images on the visible solar disk.
Region 11982 [S10W72] decayed quickly.
C5+ flare: long duration C8.1/2F event peaking at
Region 11986 [N14W42] decayed furthe rand was quiet.
Region 11987 [S02W18] was mostly quiet and stable.
Region 11989 [N08W06] decayed slowly and quietly.
Region 11990 [S13E26] was mostly quiet and decayed slowly. The magnetic delta structure in the large spot is not as strong as it used to be. The negative polarity spots could be split off soon unless the recent development stops.
Region 11991 [S24E40] has matured but could still produce C and minor M class flares. C5+ flares: M1.1 at 00:48 UTC.
Region 11992 [S19W07] decayed slowly and quietly.
Region 11993 [N17E32] developed further and has a weak magnetic delta structure in a trailing penumbra.
New region 11994 [S07W17] emerged on February 23 and was numbered by SWPC 5 days later.
New region 11995 [S17E20] emerged on February 27 and was initially considered to be part of AR 11990. The region has polarity intermixing.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3141 [S06W77] decayed further and was quiet.
S3156 [N08E05] was quiet and stable.
S3163 [S08E08] was quiet and stable.
S3168 [S10W53] was mostly quiet and stable.
S3169 [N11E19] was quiet and stable.
New region S3173 [N15E48] emerged with a penumbra spot.
New region S3174 [S08W12] emerged with a few spots.
February 26-28: 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 Eart 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 occasionally unsettled on March 1-3.
|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
rotated out of view
SWPC has adopted the spots of AR S3168
|S3168||2014.02.26||13||8||S10W53||0250||EAO||AR 11988 for SWPC|
|Total spot count:||149||178||98|
|Sunspot number:||279||348||258||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||210||232||152||(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):||167||122||142||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|
|2014.01||157.4||152.4||82.0||(71.0 projected, -0.8)||5.44|
|166.3||174.6 (2A/2B) / 119.5 (2C)||(71.2 projected, +0.2)||(10.8)|
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.