Last major update issued on March 11, 2014 at 04:45 UTC.
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[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]
The geomagnetic field was quiet on March 10. Solar wind speed at SOHO ranged between 277 and 329 km/s.
Solar flux at 20h UTC on 2.8 GHz was 151.5 (decreasing 20.7 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 154.1. The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.4). Three hour interval K indices: 10121001 (planetary), 11132312 (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 8 active regions in 2K resolution (SN: 229) and 8 active regions in 1K resolution (SN: 170) SDO images on the visible solar disk.
Region 11991 [S25W82] was quiet and stable.
Region 11996 [N14W51] developed quickly in the leading and central sections. There is at least 1 magnetic delta structure centrally. Further M class flares are possible. C5+ flare: M1.4 at 23:00 UTC. The region was the source of an M3.5 flare at 03:50 UTC on March 11.
Region 11998 [S09E03] was quiet and stable.
Region 12000 [S10W14] decayed slowly and quietly.
Region 12002 [S19E37] developed quickly and has 2 magnetic delta structures. Further M class flaring is likely. C5+ flares: M1.1 at 00:26, M1.0 at 04:08, C6.1 at 10:43, C6.0 at 11:42 (attributed to AR 11996 by SWPC), M1.7 at 15:28 UTC. Filament eruptions were noted starting at 17:29 UTC to the east of the region (and was associated with a CME) and at 22:42 UTC to the west of the region.
New region 12003 [N07W11] emerged on March 9 and was numbered by SWPC the next day.
New region 12004 [S08E64] rotated into view on March 9 and got its NOAA number the following day.
Spotted regions not numbered (or interpreted differently) by SWPC:
New region S3208 [N05E62] emerged with a penumbra spot.
March 8-10: 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 11. On March 12-13 there is a chance of a few unsettled intervals due to 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
|8||N19W92||0040||DSO||rotated out of view|
|Total spot count:||62||149||90|
|Sunspot number:||122||229||170||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||92||175||116||(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):||73||80||94||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||153.0 (1)||51.4 (2A) / 159.2 (2B) / 120.5 (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.