Solar Terrestrial Activity Report

Activity chart

Last major update issued on February 6, 2014 at 05:30 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update February 1, 2014)] [Cycle 24 progress (last update February 1, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update February 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update February 1, 2014)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update February 1, 2014)]

[POES auroral activity level since October 2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated February 1, 2014]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was very quiet on February 5. Solar wind speed at SOHO ranged between 316 and 400 km/s.

Solar flux at 20h UTC on 2.8 GHz was 193.5 (increasing 9.4 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 149.0. The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.0). Three hour interval K indices: 11101011 (planetary), 11103322 (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 14 active regions in 2K resolution (SN: 385) and 13 active regions in 1K resolution (SN: 263) SDO images on the visible solar disk.

Region 11967 [S12W34] decayed losing penumbral area and spots. The largest penumbral structure has a strong magnetic delta structure which has the potential to produce a major flare. C5+ flares: C5.2 at 12:50, M1.3 at 16:02, C8.6 at 18:44 UTC.
Region 11968 [N11W33] gained penumbral area. The region is slowly becoming more complex and has a small magnetic delta structure in the northern central section.  An M class flare is possible.
Region 11970 [S17E13] was quiet and stable.
Region 11971 [S12E40] developed with many new spots forming.
New region 11972 [S13W10] emerged on February 2 and was numbered by SWPC 3 days later. The region decayed during the latter half of the day.
New region 11973 [N07E66] rotated into view on February 4 and was numbered the next day by SWPC.
New region 11974 [S11E77] rotated fully into view.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3079 [S09W23] was quiet and stable.
S3084 [S17E05] lost the spot from the previous day and gained several penumbra spots.
S3088 [S12W16] reemerged with a few penumbra spots.
S3090 [N12E17] was quiet and stable.
S3091 [N04W37] decayed slowly and quietly.
S3092 [S08E42] was quiet and stable.
New region S3096 [N15E66] emerged with a penumbra spot.

Coronal mass ejections (CMEs)

February 3-5: 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 (CH602) will rotate into an Earth facing position on February 5-6.

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 fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet to unsettled on February 6-7. On February 8-9 quiet to active conditions are possible due to effects from CH602.

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
11967 2014.01.26
2014.01.27
82 68 38 S12W38 1500 FKC FKC beta-gamma-delta

area: 1410

location: S12W34

 

11968 2014.01.27 49 87 44 N09W36 0430 EKC EKC beta-gamma-delta

area: 0990

location: N11W33

11969 2014.01.28
2014.02.01
2     S10W87 0010 BXO     rotated out of view
S3073 2014.01.28       N18W37         plage
S3075 2014.01.29       S12W09           plage
S3077 2014.01.30       N13W58           plage
S3079 2014.01.31   14 6 S09W23 0035   BXO  
11970 2014.02.01
2014.02.02
6 8 6 S18E12 0020 CRO DRO

 

S3082 2014.02.01       N07E23           plage
S3084 2014.02.02   4 2 S17E05 0012   BXO  
11972 2014.02.02
2014.02.05
1 3 2 S13W10 0007 AXX BXO  
S3086 2014.02.02       N09W24           plage
S3087 2014.02.02       S28W31           plage
S3088 2014.02.03   5 2 S12W16 0015   BXO    
11971 2014.02.03
2014.02.04
11 28 13 S12E43 0050 CSO DAO area: 0110
S3090 2014.02.03   3 3 N12E17 0013   AXX  
S3091 2014.02.04   3 1 N04W37 0009   BXO  
S3092 2014.02.04   4 3 S08E42 0015   BXO  
11973 2014.02.04
2014.02.05
2 7 6 N06E63 0030 CRO CAO location: N07E66

area: 0050

11974 2014.02.04
2014.02.05
1 10 7 S11E76 0040 HSX DSO area: 0220
S3096 2014.02.05   1   N15E66 0001   AXX    
Total spot count: 154 245 133  
Sunspot number: 234 385 263  (total spot count + 10 * number of spotted regions)
Weighted SN: 190 283 171  (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): 140 135 145 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 solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number Average ap
(3)
Measured 1 AU
2011.11 153.5   96.7 (cycle peak) 61.1 (+1.2) 5.55
2012.02 106.5   32.9 66.9 (+1.4) 8.81
2012.11 121.3 118.3 61.8 59.7 (+1.1) 7.08
2012.12 108.6 105.0 40.8 59.6 (-0.1) 3.44
2013.01 127.1 123.1 62.9 58.7 (-0.9) 4.69
2013.02 104.3 101.8 38.0 58.4 (-0.3) 6.11
2013.03 111.3 110.2 57.9 57.5 (-0.9) 10.56
2013.04 124.8 125.9 72.4 57.9 (+0.4) 5.40
2013.05 131.4 134.3 78.7 59.9 (+2.0) 9.73
2013.06 110.1 113.7 52.5 62.6 (+2.7) 12.60
2013.07 115.5 119.3 57.0 65.5 (+2.9) 9.47
2013.08 114.6 118.3 66.0 (67.8 projected, +2.3) 8.27
2013.09 102.6 103.7 36.9 (69.6 projected, +1.8) 5.23
2013.10  132.1 131.2 85.6 (69.3 projected, -0.3) 7.71
2013.11  148.3 145.1 77.6 (67.5 projected, -1.8) 5.68
2013.12 147.7 143.1 90.3 (66.7 projected, -0.8) 4.68
2014.01 157.4
(cycle peak)
152.4 82.0 (66.9 projected, +0.2) 5.4
2014.02 187.3 (1)   32.0 (2A) / 179.0 (2B) / 103.6 (2C) (65.9 projected, -1.0) (4.0)

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 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.