Solar Terrestrial Activity Report

Activity chart

Last major update issued on February 1, 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 31. Solar wind speed at SOHO ranged between 379 and 421 km/s. A disturbance began late in the day, probably related to a recurrent co-rotating interaction region.

Solar flux at 20h UTC on 2.8 GHz was 153.5 (increasing 3.8 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 148.1. The Potsdam WDC planetary A index was 7 (STAR Ap - based on the mean of three hour interval ap indices: 6.8). Three hour interval K indices: 12111223 (planetary), 12112223 (Boulder).

The background x-ray flux is at the class B5 level.

At the time of counting spots (see image time), spots were observed in 10 active regions using 2K resolution (SN: 280) and 10 active regions using 1K resolution (SN: 190) SDO images on the visible solar disk.

Region 12268 [S09W49] decayed quickly, particularly in the trailing polarity section where only one of the spots had umbra at the end of the day.
Region 12271 [N18W70] decayed slowly and quietly.
Region 12272 [N12W08] decayed slowly and quietly.
Region 12273 [S03W68] decayed further and could soon become spotless.
Region 12275 [S17W80] decayed further and was quiet.
Region 12276 [S08W17] decayed and could soon become spotless.
Region 12277 [N08E36] lost spots and penumbral area in the intermediate spot section. A magnetic delta formed in a leading penumbra and the region could produce an M class flare.
Region 12278 [S08W00] was quiet and stable.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4186 [S10E21] was quiet and stable.
New region S4189 [S18W31] emerged with a few penumbra spots.

C2+ flares (GOES):

Magnitude Peak time (UTC) Location AR Comment
         

Coronal mass ejections (CMEs)

January 29-31: 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]

An extension of the southern polar coronal hole could be associated with a co-rotating interaction region transiting the central meridian on January 29-30.

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 February 1-3 with a chance of active conditions on February 1.

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
12268 2015.01.21
2015.01.22
23 40 22 S10W44 0480 FKC EAI  

area: 0300

location: S09W49

12270 2015.01.22
2015.01.23
      S18W57           plage
12271 2015.01.23
2015.01.25
6 6 5 N17W70 0220 EAO EAO

area: 0330

12278 2015.01.25
2015.01.29
1 19 5 S08W04 0010 AXX BXO area: 0030
12272 2015.01.25
2015.01.26
1 9 4 N12W09 0020 HAX CRO  
12273 2015.01.25
2015.01.26
2 3 1 S03W69 0020 HRX AXX  
12274 2015.01.25
2015.01.26
      S03W78           plage
12275 2015.01.26 5 4 2 S17W80 0080 DAO CAO area: 0040
S4180 2015.01.26       N23W58           plage
12276 2015.01.27
2015.01.28
3 3 1 S07W16 0010 BXO AXX  
S4182 2015.01.27       N17W58           plage
12277 2015.01.27
2015.01.28
32 87 46 N08E33 0480 FKC FKC beta-gamma-delta

area: 0620

location: N08E36

S4185 2015.01.28       S23W44           plage
S4186 2015.01.30   5 1 S10E21 0010   AXX  
S4187 2015.01.30       S37W31         plage
S4189 2015.01.31   4 3 S18W31 0011   BXO    
Total spot count: 73 180 90  
Sunspot number: 153 280 190  (total spot count + 10 * number of spotted regions)
Weighted SN: 111 208 118  (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): 92 98 105 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
2015.01 141.9 (1)   101.3 (2A/2B) / 77.3 (2C) (66.5 projected, -1.2) (8.9)

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.