Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 5, 2014 at 06:25 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, 2014)] [Cycle 24 progress (last update January 1, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update January 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update January 1, 2014)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update January 1, 2014)]

[POES auroral activity level since October 2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated December 16, 2013]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was quiet on January 4. Solar wind speed at SOHO ranged between 460 and 556 km/s under the weak influence of a high speed stream from CH598.

Solar flux measured at 18h UTC on 2.8 GHz was 213.3 (increasing 47.8 over the last solar rotation, the measurement at 20h was strongly influenced by a long duration M4 event). The 90 day 10.7 flux at 1 AU was 143.3. The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 5.1). Three hour interval K indices: 11122221 (planetary), 11122231 (Boulder).

The background x-ray flux is at the class C2 level.

At the time of counting spots (see image time) spots were observed in 13 active regions in 2K resolution (SN: 351) and 9 active regions in 1K resolution (SN: 200) SDO images on the visible solar disk.

Region 11937 [S13W56] developed further and could produce C and minor M class flares.
Region 11938 [S15W40] decayed slowly and quietly.
Region 11941 [S13W77] decayed slowly and quietly.
Region 11942 [N10E08] was quiet and stable.
Region 11943 [S12E19] was mostly unchanged.
C5+ flares: long duration M4.0 peaking at 19:46 UTC. This event occurred in the trailing polarity area and was probably triggered by interaction with AR 11944. A large and wide asymmetric full halo CME was observed in LASCO imagery.
Region 11944 [S09E37] is a large and complex region capable of producing major M and X class flares. A few small magnetic delta structures are observed, one is located in the northwestern part of the huge leading penumbra.
C5+ flares: C5.6 at 06:40, M1.3/2N at 10:16, C9.4 at 15:41 UTC.
Region 11945 [N10W10] decayed slowly and quietly.
New region 11946 [N09E37] emerged early in the day.

Spotted regions not numbered (or interpreted differently) by SWPC:
S2983 [N21E52] was quiet and stable.
S2986 [S26E06] was quiet and stable.
New region S2988 [N20E21] emerged with a penumbra spot.
New region S2989 [N00W15] emerged with penumbra spots.
New region S2990 [S09W18] emerged with penumbra spots.

AR 11936 produced an M1.9 flare at 22:52 UTC while at the southwest limb. This event may have been associated with a weak increase in proton flux levels.

Coronal mass ejections (CMEs)

January 2-3: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
January 4: A full halo CME was observed late in the day after the M4 event in AR 11943. This CME could reach Earth on January 7.

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

No obvious coronal holes are currently near Earth facing positions.

Coronal hole map

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 fair to good.

Forecast

The geomagnetic field is expected to be quiet on January 5-6. On January 7 the CME observed late on January 4 could reach Earth and cause unsettled to major storm conditions.

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: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% 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 STAR SDO SWPC STAR Current Previous
2K 1K
11936 2013.12.22
2013.12.23
2     S15W90 0060 HSX     rotated out of view

location: S17W95

11937 2013.12.25
2013.12.26
14 33 19 S12W58 0080 DAC DAC beta-gamma

area: 0180

location: S13W56

11938 2013.12.26
2013.12.27
3 10 3 S14W45 0010 HRX CRO area: 0025

location: S15W40

S2959 2013.12.27       N18W38         plage
11941 2013.12.28
2013.12.31
1 1 1 S13W78 0020 HRX HRX  
S2965 2013.12.29       S28W36           plage
S2966 2013.12.29       S14W19           plage
S2971 2013.12.30       S20W07         plage
11943 2013.12.30
2013.12.31
3 21 10 S11E17 0020 HRX DRO area: 0055

location: S12E19

11942 2013.12.30
2013.12.31
1 9 6 N10E08 0030 HSX CSO area: 0050
11944 2013.12.31
2014.01.01
60 122 59 S08E38 1470 FKC FKC beta-gamma-delta

area: 2500

S2977 2013.12.31       N14W29           plage
11945 2014.01.01
2014.01.02
2 3 3 N11W12 0010 AXX BXO location: N10W10
S2980 2014.01.01       S04W19           plage
S2983 2014.01.03   2   N21E52 0004   BXO  
S2984 2014.01.03       N38W18         plage
S2986 2014.01.03   2   S26E06 0006   BXO  
11946 2014.01.04 2 12 7 N12E41 0010 BXO DRI   location: N09E37

area: 0130

S2988 2014.01.04   1   N20E21 0002   AXX    
S2989 2014.01.04   2 2 N00W15 0012   BXO    
S2990 2014.01.04   3   S09W18 0009   BXO    
Total spot count: 88 221 110  
Sunspot number: 178 351 200  (total spot count + 10 * number of spotted regions)
Weighted SN: 122 253 142  (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): 107 123 110 k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for STAR SDO 2K, k = 0.55 for STAR SDO 1K

Monthly solar cycle data

Month Average measured solar flux International sunspot number (SIDC) Smoothed sunspot number Average ap
(3)
2011.11 153.5 (cycle peak) 96.7 (cycle peak) 61.1 (+1.2) 5.55
2012.02 106.5 32.9 66.9 (+1.4)
possible cycle 24 max
8.81
2012.10 123.3 53.3 58.6 (+0.5) 9.97
2012.11 121.3 61.8 59.7 (+1.1) 7.08
2012.12 108.6 40.8 59.6 (-0.1) 3.44
2013.01 127.1 62.9 58.7 (-0.9) 4.69
2013.02 104.3 38.0 58.4 (-0.3) 6.11
2013.03 111.3 57.9 57.5 (-0.9) 10.56
2013.04 124.8 72.4 57.9 (+0.4) 5.40
2013.05 131.4 78.7 59.9 (+2.0) 9.73
2013.06 110.1 52.5 62.6 (+2.7) 12.60
2013.07 115.5 57.0 (65.4 projected, +2.8) 9.47
2013.08 114.6 66.0 (67.8 projected, +2.4) 8.27
2013.09 102.6 36.9 (70.1 projected, +2.3) 5.23
2013.10  132.1 85.6 (70.0 projected, -0.1) 7.71
2013.11  148.3 77.6 (68.1 projected, -1.9) 5.68
2013.12 147.7 90.3 (67.4 projected, -0.7) 4.6
2014.01 178.9 (1) 18.7 (2A) / 144.8 (2B) / 96.5 (2C) (67.6 projected, +0.2) (10.6)

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 SIDC 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 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.