Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 4, 2014 at 06:30 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 3. Solar wind speed at SOHO ranged between 465 and 558 km/s under the weakening influence of a high speed stream from CH598.

Solar flux measured at 20h UTC on 2.8 GHz was 182.3 (increasing 25.4 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 142.2. The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.4). Three hour interval K indices: 21222221 (planetary), 22333322 (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 15 active regions in 2K resolution (SN: 347) and 13 active regions in 1K resolution (SN: 232) SDO images on the visible solar disk.

Region 11936 [S17W82] decayed slowly and quietly.
Region 11937 [S12W42] developed significantly as new flux emerged. The region has polarity intermixing and could produce C flares.
Region 11938 [S15W27] decayed slowly and quietly.
Region 11940 [S11W83] rotated partly out of view.
Region 11941 [S13W62] decayed slowly and quietly.
Region 11942 [N10E22] was quiet and stable.
Region 11943 [S12E31] was quiet and stable.
Region 11944 [S08E52] is a large and complex region capable of producing major M and X class flares. The region developed quickly in the eastern part with many new spots emerging and is currently the largest region observed during cycle 24. There is a weak magnetic delta structure in a small northern penumbra.
C5+ flares: C5.9 at 10:42, M1.0 at 12:50, long duration C6.9 event peaking at 15:35, M1.1 at 21:14 UTC.
Region 11945 [N10E04] ewas quiet and stable.

Spotted regions not numbered (or interpreted differently) by SWPC:
S2959 [N18W25] reemerged with penumbra spots.
S2971 [S20E06] was quiet and stable.
New region S2983 [N19E62] emerged with 2 spots.
New region S2984 [N38W05] emerged with a penumbra spot at a relatively high latitude.
New region S2985 [S05W54] emerged with a penumbra spot.
New region S2986 [S26E27] emerged with penumbra spots.

Coronal mass ejections (CMEs)

January 1-3: No obviously Earth directed CMEs were observed in LASCO and STEREO 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 recurrent trans equatorial coronal hole (CH598) was in an Earth facing position on December 29-31.

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 4-6.

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
5 6 4 S16W75 0110 DAI CAO

area: 0240

location: S17W82

11937 2013.12.25
2013.12.26
8 21 12 S12W47 0030 DAO DAI beta-gamma

area: 0120

location: S12W42

11938 2013.12.26
2013.12.27
3 14 5 S14W31 0010 BXO CRO area: 0040

location: S15W27

S2959 2013.12.27   4 1 N18W25 0010   BXO    
11941 2013.12.28
2013.12.31
3 4 3 S13W61 0020 CSO CRO  
S2965 2013.12.29       S28W23           plage
S2966 2013.12.29       S14W06         plage
S2967 2013.12.29       S35W49           plage
S2971 2013.12.30   2   S20E06 0003   AXX  
11943 2013.12.30
2013.12.31
3 8 2 S12E30 0010 CRO CRO area: 0035
11942 2013.12.30
2013.12.31
4 12 7 N10E23 0030 CAO CAO area: 0060
11940 2013.12.30
2013.12.31
4 5 3 S12W85 0070 DAO CAO area: 0100
S2975 2013.12.30       S24W50         plage
11944 2013.12.31
2014.01.01
37 105 56 S09E53 1280 FKC FKC beta-gamma-delta

area: 2500

S2977 2013.12.31       N14W16           plage
11945 2014.01.01
2014.01.02
5 10 6 N10E04 0010 DRO DRO area: 0040
S2980 2014.01.01       S04W06           plage
S2983 2014.01.03   2 1 N19E62 0007   AXX    
S2984 2014.01.03   1 1 N38W05 0004   AXX    
S2985 2014.01.03   1   S05W54 0003   AXX    
S2986 2014.01.03   2 1 S26E27 0010   AXX    
Total spot count: 72 197 102  
Sunspot number: 162 347 232  (total spot count + 10 * number of spotted regions)
Weighted SN: 113 239 144  (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): 97 121 128 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
2014.01 167.5 (1) 12.9 (2A) / 133.7 (2B) / 95.2 (2C) (67.6 projected, +0.2) (12.4)

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.