Last major update issued on March 12, 2014 at 03:40 UTC.
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[Solar cycles 23-24 (last update March 1, 2014)] [Cycle 24 progress (last update March 1, 2014) ]
[Solar cycles 1-20]
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[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]
The geomagnetic field was very quiet on March 11. Solar wind speed at SOHO ranged between 288 and 323 km/s.
Solar flux at 20h UTC on 2.8 GHz was 164.6 (increasing 4.5 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 154.0. The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.8). Three hour interval K indices: 11111111 (planetary), 00112311 (Boulder).
The background x-ray flux is at the class B8 level.
At the time of counting spots (see image time) spots were observed in 9 active regions in 2K resolution (SN: 258) and 9 active regions in 1K resolution (SN: 189) SDO images on the visible solar disk.
Region 11996 [N14W66] still has a magnetic delta
structure in a central penumbra and could produce further M class flaring.
C5+ flares: M3.5/1F at 03:44, C6.7 at 18:43, C6.9
at 21:56 UTC.
Region 11998 [S10W11] lost penumbral area on the leader spots. There are many penumbra spots visible on both polarities.
Region 11999 [S16W58] reemerged with a penumbra spot.
Region 12000 [S10W25] was quiet and stable.
Region 12002 [S19E23] gained penumbral area but is a little less complex magnetically than one day ago with only one minor magnetic detla structure present. M class flares are possible. C5+ flares: C9.7/1F at 16:27, C8.0 at 19:47 UTC.
Region 12003 [N06W23] developed slowly and quietly.
Region 12004 [S09E50] was quiet and stable.
Spotted regions not numbered (or interpreted differently) by SWPC:
New region S3209 [N12E85] rotated partly into view with a large spot.
New region S3210 [S18W61] emerged to the southwest of AR 11999 with several penumbra spots.
AR 11991 at the southwest limb produced a C6.7 flare at 10:17 and an M1.4 flare at 12:07 UTC.
March 9-11: 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 small southern hemisphere coronal hole (CH607) was in an Earth facing position on March 9.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle latitudes is fair. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet on March 12-14 with a chance of a few unsettled intervals on March 12-13 due to possible effects from CH607.
|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:||58||168||99|
|Sunspot number:||108||258||189||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||78||206||137||(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):||65||90||104||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
|2013.09||102.6||103.7||36.9||(72.8 projected, +3.8)||5.23|
|2013.10||132.1||131.2||85.6||(73.8 projected, +1.0)||7.71|
|2013.11||148.3||145.1||77.6||(72.7 projected, -1.1)||5.68|
|2013.12||147.7||143.1||90.3||(71.6 projected, -1.1)||4.68|
|2014.01||157.4||152.4||82.0||(71.6 projected, 0.0)||5.44|
|166.3||102.8 (cycle peak)||(70.9 projected, -0.7)||10.70|
|2014.03||154.1 (1)||54.8 (2A) / 154.5 (2B) / 119.9 (2C)||(71.0 projected, +0.1)||(3.9)|
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.