Last major update issued on March 17, 2015 at 05:00 UT.
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[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]
The geomagnetic field was quiet to unsettled on March 16. Solar wind speed at SOHO ranged between 341 and 440 km/s. A disturbance related to a co-rotating interaction region began early in the day.
Solar flux at 20h UTC on 2.8 GHz was 117.2 (decreasing 1.3 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 134.9. The Potsdam WDC planetary A index was 11 (STAR Ap - based on the mean of three hour interval ap indices: 10.6). Three hour interval K indices: 23332310 (planetary), 23322321 (Boulder).
The background x-ray flux is at the class B4 level.
At the time of counting spots (see image time), spots were observed in 10 active regions using 2K resolution (SN: 153) and 7 active regions using 1K resolution (SN: 96) SDO images on the visible solar disk.
Region 12297 [S18W48] decayed slowly. The largest penumbra
still has a magnetic delta and could produce further M class flares.
Region 12299 [S05E08] decayed slowly and quietly.
Region 12301 [S17W26] decayed slowly and quietly.
Spotted regions not numbered (or interpreted
differently) by SWPC:
S4278 [N20W49] reemerged with a penumbra spot.
S4283 [S25W25] reemerged with a penumbra spot.
S4284 [N10W38] developed slowly and quietly.
New region S4285 [N19E79] rotated into view with a single spot.
New region S4286 [N08W23] emerged with a penumbra spot.
New region S4287 [N18W21] emerged with penumbra spots.
New region S4288 [S09W27] was observed with penumbra spots.
C2+ flares (GOES):
|Magnitude||Peak time (UTC)||Location||AR||Comment|
|C4.7||00:17||12297||added from SDO/EVE|
SDO/EVE/ESP XRS-B proxy
March 14, 16: No obviously
Earth directed CMEs were observed.
March 15: An asymmetric full halo CME was observed after the C9 LDE in and near AR 12297 early in the day.
history (since October 2002)]
[Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago]
An extension (CH659) of the southern polar coronal hole rotated across the central meridian on March 14-16. This, and a northern hemisphere coronal hole, could be associated with co-rotating interaction regions.
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.
The geomagnetic field is expected to be quiet to minor storm conditions on March 17-18 due to effects from co-rotating interaction regions and CH659 and quiet to active on March 19. March 18 could see the arrival of the CME observed on March 15.
|Coronal holes (1)||Coronal mass ejection (2)||M and X class flares (3)|
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.
|Active region||Date numbered
|Spot count||Location at midnight||Area||Classification||SDO / HMI 4K continuum
image with magnetic polarity overlay
|Total spot count:||27||53||26|
|Sunspot number:||57||153||96||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||37||68||41||(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):||34||54||53||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
|166.3||102.3 (cycle peak)||78.4 (+1.1)||10.70|
(likely solar max)
|2014.09||146.6||148.1||87.6||(71.6 projected, -4.0)||9.78|
|2014.10||153.4||152.9||60.6||(69.2 projected, -2.4)||8.96|
|2014.11||154.8||151.4||70.1||(67.4 projected, -1.8)||9.33|
|2014.12||158.7||153.8||78.0||(66.3 projected, -1.1)||11.24|
|2015.01||141.9||137.3||67.0||(65.1 projected, -1.2)||9.46|
|2015.02||129.1||126.0||44.8||(63.6 projected, -1.5)||9.92|
|2015.03||(124.5)||24.1 (2A) / 46.6 (2B) / 53.2 (2C)||(61.6 projected, -2.0)||(10.4)|
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.