Last major update issued on February 16, 2015 at 05:25 UTC.
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The geomagnetic field was quiet on February 15. Solar wind speed at SOHO ranged between 296 and 352 km/s. ACE EPAM (proton) indices began to increase slowly on February 13 and had weak peaks on February 14 and 15. ACE SWEPAM displays a weak solar wind disturbance arriving early on February 14, this disturbance had no obvious geomagnetic effects. A slightly stronger disturbance began late on February 14 and caused a minor increase in geomagnetic activity on February 15. The most likely source of these disturbances is the partial halo CME observed early on February 10.
Solar flux at 20h UTC on 2.8 GHz was 119.6 (decreasing 10.4 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 147.1. The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 4.9). Three hour interval K indices: 02212111 (planetary), 12322211 (Boulder).
The background x-ray flux is at the class B3 level.
At the time of counting spots (see image time), spots were observed in 8 active regions using 2K resolution (SN: 123) and 7 active regions using 1K resolution (SN: 94) SDO images on the visible solar disk.
Region 12282 [N14W25] decayed slowly and quietly.
Region 12284 [N15E28] decayed slowly and quietly.
New region 12285 [S08W14] emerged on February 14 and was numbered the next day by SWPC.
Spotted regions not numbered (or interpreted
differently) by SWPC:
S4210 [N09W08] was quiet and stable.
S4211 [S17W04] decayed slowly and quietly.
S4214 [N08W24] decayed slowly and quietly.
S4222 [S06E17] decayed slowly and quietly.
New region S4224 [S20E35] emerged with a penumbra spot.
C2+ flares (GOES):
|Magnitude||Peak time (UTC)||Location||AR||Comment|
February 13-15: No obviously Earth directed CMEs were observed in LASCO imagery.
history (since October 2002)]
[Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago]
A northern hemisphere coronal hole (CH654) will rotate across the central meridian on February 15-16.
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 February 16-17. A weak disturbance is possible on February 18-19 if CH654 has a geoeffective extension or is associated with a co-rotating interaction region.
|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
split off from AR S4214
|Total spot count:||15||43||24|
|Sunspot number:||45||123||94||(total spot count + 10 * number of spotted regions)|
|Weighted SN:||23||59||40||(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):||27||43||52||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)
|2014.08||124.7||127.9||74.7||(76.2 projected, -2.4)||7.71|
|2014.09||146.6||148.1||87.6||(73.0 projected, -3.2)||9.78|
|2014.10||153.4||152.9||60.6||(70.5 projected, -2.5)||8.96|
|2014.11||154.8||151.4||70.1||(68.8 projected, -1.7)||9.33|
|2014.12||158.7||153.8||78.0||(67.7 projected, -1.1)||11.24|
|2015.01||141.9||137.3||67.0||(66.5 projected, -1.2)||9.46|
|2015.02||139.4 (1)||43.6 (2A) / 81.3 (2B) / 76.5 (2C)||(64.9 projected, -1.6)||(8.2)|
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.