Last major update issued on March 31, 2014 at 04:40 UTC.
[Solar and geomagnetic data - last month (updated
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update March 1, 2014)] [Cycle 24 progress (last update March 1, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update March 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update March 1, 2014)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update March 1, 2014)]
[POES auroral activity level since October
2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated March 16, 2014]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]
The geomagnetic field was quiet on March 30. Solar wind speed at SOHO ranged between 350 and 445 km/s.
Solar flux at 20h UTC on 2.8 GHz was 148.4 (decreasing 12.6 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 155.2 (new high for cycle 24). The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.9). Three hour interval K indices: 21110111 (planetary), 20112321 (Boulder).
The background x-ray flux is at the class B9 level.
At the time of counting spots (see image time), spots were observed in 16 active regions in 2K resolution (SN: 292) and 14 active regions in 1K resolution (SN: 210) SDO images on the visible solar disk.
Region 12014 [S13W78] decayed slowly and quietly.
Region 12017 [N10W49] decayed and lost the magnetic delta structure during the day. There is still polarity intermixing and C flares are possible. C5+ flares: M2.1/1N at 11:55, C7.6 at 21:15 UTC.
Region 12018 [N05W42] decayed slowly and quietly.
Region 12020 [S15W13] decayed slowly and quietly.
Region 12021 [S12E25] developed slowly and was mostly quiet. C and minor M class flares are possible.
Region 12022 [N17E38] was quiet and stable.
Region 12024 [N18E08] was quiet and stable.
New region 12025 [S23W18] emerged on March 27 and was numbered by SWPC 3 days later.
New region 12026 [S11E79] rotated into view as a compact region with many small spots. The region has polarity intermixing. C and M class flaring is possible.
Spotted regions not numbered (or interpreted differently) by SWPC:
S3276 [S11E13] was quiet and stable.
S3277 [S28E13] was quiet and stable.
S3281 [S08W37] was quiet and stable.
New region S3283 [S25W70] emerged with a few spots.
New region S3284 [N12E86] rotated partly into view.
New region S3285 [S12W10] emerged with a few spots.
New region S3286 [S06W60] emerged with penumbra spots.
March 28, 30: No obviously Earth directed CMEs were observed in LASCO and
March 29: An asymmetric full halo CME was observed after the X1 flare in AR 12017. The leading edge of the CME will likely reach Earth sometime between late on March 31 and noon on April 1. The CME core was not Earth directed.
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 (CH609) rotated into an Earth facing position on March 28-29.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle latitudes is poor to fair. Propagation on long distance northeast-southwest paths is poor.
The geomagnetic field is expected to be quiet to unsettled on March 31 due to effects from CH609. Quiet to active conditions are possible on April 1 due to CME and coronal hole effects, while April 2 could see quiet to unsettled conditions.
|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: 0-30% probability, Yellow: 30-70% probability, Red: 70-100% 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
SWPC apparently includes the spots of AR S3285
|1||S16W91||0010||AXX||rotated out of view|
|Total spot count:||42||132||70|
|Sunspot number:||122||292||210||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||65||179||117||(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||102||116||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||149.8 (1)||136.5 (2A) / 141.0 (2B) / 114.0 (2C)||(71.0 projected, +0.1)||(4.9)|
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.