Solar Terrestrial Activity Report

Activity chart

Last major update issued on February 17, 2015 at 05:15 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 to unsettled on February 16. Solar wind speed at SOHO ranged between 314 and 356 km/s. The total field of the interplanetary magnetic field increased after 10h UTC and Bz became gradually more southwards after 18h UTC. This caused an increase in geomagnetic disturbance levels.

Solar flux at 20h UTC on 2.8 GHz was 118.1 (decreasing 7.5 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 146.5. The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 4.8). Three hour interval K indices: 00111123 (planetary), 01112222 (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: 130) and 6 active regions using 1K resolution (SN: 83) SDO images on the visible solar disk.

Region 12282 [N13W38] was quiet and stable.
Region 12284 [N13E18] decayed slowly and quietly.
Region 12285 [S09W28] decayed slowly and quietly.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4211 [S19W16] was quiet and stable.
S4214 [N07W37] decayed slowly and quietly.
S4217 [S08W13] reemerged with penumbra spots.
S4224 [S17E21] was quiet and stable.
New region S4226 [N13E04] was observed with penumbra spots.

C2+ flares (GOES):

Magnitude Peak time (UTC) Location AR Comment
         

Coronal mass ejections (CMEs)

February 14-16: 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 poor to fair. Propagation on long distance northeast-southwest paths is poor to fair.

Forecast

The geomagnetic field is expected to be quiet to unsettled with a chance of active intervals on February 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
12282 2015.02.07 10 14 8 N11W37 0210 CSO CAO

location: N13W38

area: 0140

split off from AR S4214

S4206 2015.02.07       S12W39            
S4207 2015.02.08       N07W56            
S4210 2015.02.10       N09W21          
S4211 2015.02.10   7 5 S19W16 0020   BXO images/AR_S4211_20150216_2345.png images/AR_S4211_20150215_2345.png  
S4214 2015.02.11   9 3 N07W37 0170   CAO  
12283 2015.02.12       N07W66            
S4217 2015.02.12   5 1 S08W13 0010   BXO    
12284 2015.02.12
2015.02.13
1 6 2 N15E16 0000 AXX BXO area: 0012
S4221 2015.02.13       S17E38            
S4222 2015.02.14       S06E04          
12285 2015.02.14
2015.02.15
3 5 4 S09W29 0010 BXO CRO area: 0015
S4224 2015.02.15   2   S17E21 0003   AXX    
S4226 2015.02.16   2   N13E04 0006   AXX  

 

Total spot count: 14 50 23  
Sunspot number: 44 130 83  (total spot count + 10 * number of spotted regions)
Weighted SN: 19 63 36  (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): 26 46 46 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
2015.02 138.1 (1)   45.1 (2A) / 79.0 (2B) / 76.2 (2C) (64.9 projected, -1.6) (8.0)

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.