Solar Terrestrial Activity Report

Activity chart

Last major update issued on February 7, 2015 at 05:20 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 6. Solar wind speed at SOHO ranged between 362 and 441 km/s.

Solar flux at 20h UTC on 2.8 GHz was 143.3 (decreasing 8.6 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 148.9. 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: 01221110 (planetary), 01222311 (Boulder).

The background x-ray flux is at the class B7 level.

At the time of counting spots (see image time), spots were observed in 9 active regions using 2K resolution (SN: 214) and 9 active regions using 1K resolution (SN: 147) SDO images on the visible solar disk.

Region 12277 [N09W40] decayed further losing spots and penumbral area.
Region 12280 [S08E03] developed slowly and could produce a minor M class flare.
Region 12281 [N12E38] decayed slowly and quietly.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4192 [S09W13] was quiet and stable.
S4195 [N08W17] reemerged with penumbra spots.
S4196 [N12E04] reemerged with a penumbra spot.
S4198 [S19E36] was quiet and stable.
S4204 [N18E24] was quiet and stable.

C2+ flares (GOES):

Magnitude Peak time (UTC) Location AR Comment
         

Coronal mass ejections (CMEs)

February 4-6: 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 poorly defined trans equatorial coronal hole (CH652) rotated across the central meridian on February 5-6.

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.

Forecast

The geomagnetic field is expected to be quiet on February 7. A high speed stream from CH652 could cause unsettled and active intervals on February 8-9.

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
12278 2015.01.25
2015.01.29
      S08W88           plage
12277 2015.01.27
2015.01.28
20 45 21 N09W44 0200 FAI FAI beta-gamma

location: N09W40

S4186 2015.01.30       S19W35         plage
S4192 2015.02.01   9 3 S09W13 0022   AXX  
12280 2015.02.02 16 40 21 S08E03 0160 DAC DAC beta-gamma

area: 0280

12281 2015.02.03 5 15 5 N14E34 0080 CAO CAO location: N12E38
S4195 2015.02.03   6 2 N08W17 0010   BXO    
S4196 2015.02.03   1 1 N12E04 0004   AXX   plage
S4198 2015.02.04   6 2 S19E36 0014   BXO images/AR_S4198_20150206_2345.png  
S4199 2015.02.04       S32W19           plage
S4203 2015.02.05   1 1 S10W57 0005   AXX  
S4204 2015.02.05   1 1 N18E24 0003   AXX

 

Total spot count: 41 124 57  
Sunspot number: 71 214 147  (total spot count + 10 * number of spotted regions)
Weighted SN: 56 144 77  (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): 43 75 81 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
2015.02 145.8 (1)   21.5 (2A) / 100.5 (2B) / 79.3 (2C) (64.9 projected, -1.6) (13.0)

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.