Solar Terrestrial Activity Report

Activity chart

Last major update issued on February 5, 2014 at 06:00 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 quiet on February 4. Solar wind speed at SOHO ranged between 319 and 353 km/s.

Solar flux at 20h UTC on 2.8 GHz was 188.1 (decreasing 6.5 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 148.6. 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: 22111111 (planetary), 11112322 (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 14 active regions in 2K resolution (SN: 376) and 13 active regions in 1K resolution (SN: 268) SDO images on the visible solar disk.

Region 11967 [S12W22] lost penumbral area. Several magnetic delta structures are still present and an X class flare is possible. C5+ flares: M3.8/1B at 01:23 (wrongly attributed to AR 11968 by SWPC), long duration M1.2 event peaking near 03:00 (not detected by SWPC), major M5.2/1B at 04:00, C7.4 at 09:25, M1.4 at 09:49, C5.9 at 12:20, C7.7 at 13:53, C6.4 at 14:36, long duration M1.5/1N event peaking at 16:02, C5.4 at 19:41, C5.5 at 21:35 UTC.
Region 11968 [N10W19] gained many spots and is developing in the central section. While there are no magnetic delta structures currently, the region could produce minor M class flares. C5+ flare: C6.5 at 22:03 UTC
Region 11969 [S10W74] was quiet and stable.
Region 11970 [S17E27] decayed slowly and quietly.
New region 11971 [S12E55] emerged on February 3 and was numbered by SWPC the next day.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3073 [N18W24] lost the trailing spots and gained a leading polarity spot.
S3079 [S09W09] decayed slowly and quietly.
S3084 [S10E13] was quiet and stable.
S3085 [S13E03] was quiet.
S3090 [N12E30] gained penumbra spots.
New region S3091 [N04W23] emerged with a few spots.
New region S3092 [S07E57] emerged with penumbra spots.
New region S3093 [N07E79] rotated into view.
New region S3094 [S11E88] rotated partly into view.

Coronal mass ejections (CMEs)

February 2-4: 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 poor to fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet to unsettled on February 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
11967 2014.01.26
2014.01.27
73 99 54 S12W24 1580 FKC FKC beta-gamma-delta

area: 2160

location: S12W22

 

11968 2014.01.27 49 77 55 N09W22 0330 EKC EAC beta-gamma

area: 0820

location: N10W19

11969 2014.01.28
2014.02.01
4 4 2 S11W73 0030 DRO DRO  
S3073 2014.01.28   1 1 N18W24 0004   AXX  
S3075 2014.01.29       S12E04           plage
S3077 2014.01.30       N13W45           plage
S3078 2014.01.30       S23W48           plage
S3079 2014.01.31   9 4 S09W09 0025   BXO  
11970 2014.02.01
2014.02.02
4 11 5 S18E26 0020 CRO CRO

 

S3082 2014.02.01       N07E36           plage
S3084 2014.02.02   1   S10E13 0002   AXX  
S3085 2014.02.02   6 2 S13E63 0025   BXO  
S3086 2014.02.02       N09W11           plage
S3087 2014.02.02       S28W18           plage
S3088 2014.02.03       S12W01         plage
11971 2014.02.03
2014.02.04
3 12 7 S11E59 0010 BXO DRI area: 0045
S3090 2014.02.03   3 2 N12E30 0010   AXX  
S3091 2014.02.04   7 2 N04W23 0025   DRO    
S3092 2014.02.04   3 2 S07E57 0011   BXO    
S3093 2014.02.04   2 1 N07E79 0030   HRX    
S3094 2014.02.04   1 1 S11E88 0030   HRX    
Total spot count: 133 236 138  
Sunspot number: 183 376 268  (total spot count + 10 * number of spotted regions)
Weighted SN: 159 269 171  (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): 110 132 147 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
2014.02 185.7 (1)   23.6 (2A) / 165.3 (2B) / 102.4 (2C) (65.9 projected, -1.0) (4.2)

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.