Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 28, 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 January 1, 2015)] [Cycle 24 progress (last update January 1, 2015) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update January 1, 2015)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update January 1, 2015)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update January 3, 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 January 27. Solar wind speed at SOHO ranged between 347 and 480 km/s.

Solar flux at 20h UTC on 2.8 GHz was 158.1 (increasing 24.5 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 146.7. The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.4). Three hour interval K indices: 33321223 (planetary), 22323323 (Boulder).

The background x-ray flux is at the class C1 level.

At the time of counting spots (see image time), spots were observed in 11 active regions using 2K resolution (SN: 277) and 11 active regions using 1K resolution (SN: 198) SDO images on the visible solar disk.

Region 12268 [S10E08] developed in the trailing spot section and has polarity intermixing. An M class flare is possible. The region produced an M1.4 flare peaking at 04:41 UTC on January 28.
Region 12269 [N07W33] decayed slowly and quietly.
Region 12271 [N17W15] developed further and has minor M class flare potential.
Region 12272 [N12E48] was quiet and stable.
Region 12273 [S03W12] decayed slowly and could produce further C flares.
Region 12275 [S16W25] developed and might be capable of producing a minor M class flare.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4174 [S09E52] gained a few spots and was quiet.
New region S4181 [S07E39] emerged early in the day.
New region S4182 [N16W05] emerged early in the day and appeared to be decaying late in the day.
New region S4183 [N06E83] rotated partly into view. This region could be capable of producing a major flare.
New region S4184 [N22W45] emerged with a single spot.

C2+ flares (GOES):

Magnitude Peak time (UTC) Location AR Comment
C2.4 05:47 S03E01 12273  
C2.1 (LDE) 07:33   S4183  
C2.9 20:30   S4183  
C5.7 23:59   S4181  

Coronal mass ejections (CMEs)

January 25-27: 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 small southern hemisphere coronal hole (CH651) was in an Earth facing position on January 25.

Propagation

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 to fair.

Forecast

The geomagnetic field is expected to be quiet to unsettled on January 28-29 due to weak coronal hole effects.

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
12267 2015.01.18
2015.01.19
      N18W49           plage
12269 2015.01.19
2015.01.22
5 9 3 N07W36 0020 CAI BXO

 

12268 2015.01.21
2015.01.22
24 59 33 S10E09 0480 FKC FKC beta-gamma

area: 0680

12270 2015.01.22
2015.01.23
      S18W01           plage
S4166 2015.01.22       S27W36           plage
S4167 2015.01.22       N02W45           plage
S4168 2015.01.23       S10W27           plage
12271 2015.01.23
2015.01.25
10 28 15 N18W18 0120 DAI DAC

area: 0220

location: N17W15

S4172 2015.01.24       S24W15           plage
S4173 2015.01.24       S04W47           plage
S4174 2015.01.25   7 2 S09E52 0016   BXO  
12272 2015.01.25
2015.01.26
3 7 2 N13E49 0040 CSO CAO  
12273 2015.01.25
2015.01.26
6 13 10 S03W12 0090 DAO DAI  
12274 2015.01.25
2015.01.26
      S03W20         plage
12275 2015.01.26 11 25 13 S17W26 0090 DAI DAC plage
S4179 2015.01.26       N17W28         plage
S4180 2015.01.26       N23W06         plage
S4181 2015.01.27   6 3 S07E39     CRO    
S4182 2015.01.27   4 1 N16W05 0010   CRO    
S4183 2015.01.27   8 5 N06E83 0120   CAO    
S4184 2015.01.27   1 1 N22W45 0004   AXX    
Total spot count: 59 167 88  
Sunspot number: 119 277 198  (total spot count + 10 * number of spotted regions)
Weighted SN: 94 208 129  (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): 71 97 109 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 projected, -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
2015.01 139.8 (1)   84.3 (2A) / 93.3 (2B) / 74.8 (2C) (66.5 projected, -1.2) (9.1)

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.