Solar Terrestrial Activity Report

Activity chart

Last major update issued on February 16, 2015 at 05:25 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update February 1, 2015)] [Cycle 24 progress (last update February 1, 2015) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update February 1, 2015)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update February 1, 2015)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update February 1, 2015)]

[Noon SDO sunspot count 1K Reference: 4K (large file) (updated daily)]

[POES auroral activity level October 2009 - December 2012]
[Solar polar fields vs solar cycles - updated January 25, 2015]
[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]

Recent activity

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
         

Coronal mass ejections (CMEs)

February 13-15: No obviously Earth directed CMEs were observed in LASCO imagery.

Coronal holes

[Coronal hole 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.

Propagation

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.

Forecast

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)
     

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 green.
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.

Active solar regions

(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
detected
Spot count Location at midnight Area Classification SDO / HMI 4K continuum
image with magnetic polarity overlay
Comment
SWPC Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
S4198 2015.02.04       S32W46         images/AR_S4198_20150214_2345.png  
12282 2015.02.07 8 9 5 N11W24 0210 CSO CAO

location: N14W25

area: 0180

split off from AR S4214

S4206 2015.02.07       S12W26            
S4207 2015.02.08       N07W43            
S4210 2015.02.10   2 1 N09W08 0004   AXX  
S4211 2015.02.10   8 3 S17W04 0015   BXO images/AR_S4211_20150215_2345.png images/AR_S4211_20150214_2345.png  
S4212 2015.02.10       N28W48            
S4214 2015.02.11   11 8 N08W24 0200   DSO beta-gamma
12283 2015.02.12       N07W53          
S4217 2015.02.12       S04W03          
12284 2015.02.12
2015.02.13
2 3 1 N14E29 0010 BXO CRO  
S4219 2015.02.12       N17W56            
S4221 2015.02.13       S17E51            
S4222 2015.02.14   1   S06E17 0003   AXX  
12285 2015.02.14
2015.02.15
5 8 5 S09W14 0007 CRO CRO  
S4224 2015.02.15   1 1 S20E35 0003   AXX  

 

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)

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number Average ap
(3)
Measured 1 AU
2013.09 102.6 103.7 36.9 73.1 (+4.1) 5.23
2013.10  132.1 131.2 85.6 75.0 (+1.9) 7.71
2013.11  148.3 145.1 77.6 75.4 (+0.4) 5.68
2013.12 147.7 143.1 90.3 76.0 (+0.6) 4.68
2014.01 157.4 152.4 81.8 77.3 (+1.3) 5.44
2014.02 170.3
(cycle peak)
166.3 102.3 (cycle peak) 78.4 (+1.1) 10.70
2014.03 149.9 148.5 91.9 80.8 (+2.4) 4.88
2014.04 143.9 144.8 84.7 81.9 (+1.1)
(likely solar max)
7.88
2014.05 129.7 132.9 75.2 80.5 (-1.4) 5.75
2014.06 122.0 125.8 71.0 79.7 (-0.8) 6.72
2014.07 137.4 141.8 72.5 78.6 (-1.1) 4.50
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 2800 MHz.
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.