Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 2, 2015 at 05:50 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 December 3, 2014)]

[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 December 27, 2014]
[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]

Recent activity

The geomagnetic field was quiet to unsettled on January 1. Solar wind speed at SOHO ranged between 397 and 564 km/s.

Solar flux at 20h UTC on 2.8 GHz was 136.6 (decreasing 0.2 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 152.7. The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.3). Three hour interval K indices: 21211123 (planetary), 22112221 (Boulder).

The background x-ray flux is at the class B4 level.

At the time of counting spots (see image time), spots were observed in 10 active regions using 2K resolution (SN: 199) and 9 active regions using 1K resolution (SN: 140) SDO images on the visible solar disk.

Region 12246 [N18W67] was quiet and stable.
Region 12248 [S20W40] decayed slowly and quietly.
Region 12251 [S14W08] decayed slowly and quietly.
Region 12252 [S20E13] was quiet and stable.
Region 12253 [S07E37] developed further and has two magnetic deltas within the large leading penumbra. An M class flare is possible.
Region 12254 [S22W06] did not change significantly and was quiet.
New region 12255 [S13E78] rotated into view.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4114 [N13E16] was quiet and stable.
S4120 [S09W32] developed slowly and quietly.
New region S4123 [S16E28] emerged with penumbra spots.

C2+ flares (GOES):

Magnitude Peak time (UTC) Location AR Comment
C2.1 05:07 S07E50 12253  
C2.1 07:30 S06E49 12253  

Coronal mass ejections (CMEs)

December 30 - January 1: 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 trans equatorial coronal hole (CH648) will be in an Earth facing position on January 2. A corotating interaction region could be associated with the large southern hemisphere coronal hole. In that case the CIR will be in an Earth facing position on January 1-2.

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.

Forecast

The geomagnetic field is expected to be mostly quiet on January 2-3. Quiet to unsettled with a chance of active intervals is possible on January 4-6 due to 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
12246 2014.12.21 1 1 1 N19W69 0050 HSX HSX area: 0100

location: N18W67

12247 2014.12.23       S19W60        

real location: S25W59

12248 2014.12.23 1 1 1 S19W42 0050 HAX HSX

location: S20W40

area: 0100

S4103 2014.12.24       N05W46           plage
S4105 2014.12.25       S10W33           plage
12251 2014.12.26 6 13 7 S13W09 0140 DAO DAO

area: 0250

12252 2014.12.27 2 6 2 S20E11 0090 HAX CAO area: 0140

location: S20E13

S4112 2014.12.27       N03W20           plage
12253 2014.12.29
2014.12.30
16 57 28 S07E35 0460 EKC EKC beta-gamma-delta

area: 0880

S4114 2014.12.29   3   N13E16 0007   AXX  
S4115 2014.12.29       N07W26         plage
S4117 2014.12.29       S09W29           plage
S4118 2014.12.30       S15E08           plage
12254 2014.12.31 4 8 6 S22W05 0020 CRO CRO  
S4120 2014.12.31   5 2 S09W32 0018   CRO  
S4121 2014.12.31       N08W39         plage
12255 2015.01.01 1 1 1 S14E76 0060 HSX HSX   area: 0130
S4123 2015.01.01   4 2 S16E28 0010   BXO  

 

Total spot count: 31 99 50  
Sunspot number: 101 199 140  (total spot count + 10 * number of spotted regions)
Weighted SN: 69 140 91  (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): 61 70 77 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) 10.8
2015.01 136.6 (1)   3.3 (2A) / 101 (2B) / 87.9 (2C) (66.5 projected, -1.2) (6.3)

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.