Solar Terrestrial Activity Report

Activity chart

Last major update issued on February 22, 2014 at 05:05 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 to unsettled on February 21. Solar wind speed at SOHO ranged between 445 and 546 km/s.

Solar flux at 20h UTC on 2.8 GHz was 156.8 (increasing 23.6 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 149.9. The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.4). Three hour interval K indices: 32222212 (planetary), 22243212 (Boulder).

The background x-ray flux is at the class B8 level.

At the time of counting spots (see image time) spots were observed in 14 active regions in 2K resolution (SN: 320) and 13 active regions in 1K resolution (SN: 230) SDO images on the visible solar disk.

Region 11977 [S09W72] was quiet and stable.
Region 11981 [S07E06] matured and was quiet.
Region 11982 [S11E19] gained spots and penumbral area. Although there's only minor polarity intermixing, the region could produce a minor M class flare.
Region 11983 [S12E02] was quiet and stable.
Region 11984 [S16E06] was quiet and stable.
Region 11985 [N07W73] decayed early in the day, then developed slowly.
Region 11986 [N13E47] was quiet and stable.
New region 11987 [S02E78] rotated into view.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3135 [S31W23] reemerged with penumbra spots.
S3137 [S21W01] reemerged with trailing polarity penumbra spots.
S3141 [S07E18] developed with many news spots emerging.
New region S3146 [S11E50] emerged early in the day and developed slowly.
New region S3148 [S17W46] emerged early in the day and was decaying late in the day.
New region S3149 [S31W07] emerged with a penumbra spot.

Coronal mass ejections (CMEs)

February 19: A faint partial halo CME was observed after 16h and was likely associated with a filament eruption in the southern hemisphere. An extension of the CME could reach Earth on February 22.
February 20: A faint asymmetric full halo CME was observed after a C3 flare in AR 11982 early in the day. Weak effects from this CME could reach Earth on February 23.
February 21: No obvious 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 trans equatorial coronal hole (CH604) rotated into an Earth facing position on February 20-21.

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 poor to fair.

Forecast

The geomagnetic field is expected to be quiet to active on February 22-24 due to CME effects the first day and a high speed stream from CH604 on February 23-24.

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
11976 2014.02.07
2014.02.08
1     S13W94 0060 HAX    

rotated out of view

11980 2014.02.09
2014.02.14
      S13W88          

plage

11977 2014.02.10 5 5 2 S09W71 0020 CRO CRO  
S3126 2014.02.14       S25W53           plage
S3127 2014.02.15       S23W39           plage
S3128 2014.02.15       S16W10           plage
11983 2014.02.16
2014.02.18
  7 3 S14W00 0014   CRO  
11982 2014.02.16
2014.02.17
38 80 42 S10E19 0520 DKC DAC

area: 0940

11981 2014.02.16
2014.02.17
19 25 15 S07E06 0190 DAI EAI area: 0400
11984 2014.02.17
2014.02.18
2 5 3 S16E04 0010 BXO BXO area: 0020
S3135 2014.02.17   2   S31W23 0004   BXO    
S3136 2014.02.17       S23W23           plage
S3137 2014.02.17   3 2 S21W01 0010   AXX    
S3138 2014.02.18       S13W28           plage
11985 2014.02.18
2014.02.19
2 2 1 N08W71 0010 BXO BXO location: N07W73

area: 0025

11986 2014.02.19
2014.02.20
4 19 7 N14E48 0030 CAO ERO

area: 0050

S3141 2014.02.19   23 18 S07E18 0100   DRI  
S3144 2014.02.20       S16W11         plage
S3145 2014.02.20       S05W16         plage
11987 2014.02.21 1 4 3 S03E71 0030 HAX DAO   location: S02E78

area: 0280

S3146 2014.02.21   3 2 S11E50 0023   DRO    
S3148 2014.02.21   1 1 N17W46 0004   AXX    
S3149 2014.02.21   1 1 S31W07 0004   AXX    
Total spot count: 72 180 100  
Sunspot number: 152 320 230  (total spot count + 10 * number of spotted regions)
Weighted SN: 105 210 130  (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): 91 112 127 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 (69.0 projected, +3.5) 8.27
2013.09 102.6 103.7 36.9 (73.0 projected, +4.0) 5.23
2013.10  132.1 131.2 85.6 (74.0 projected, +1.0) 7.71
2013.11  148.3 145.1 77.6 (72.9 projected, -1.1) 5.68
2013.12 147.7 143.1 90.3 (71.8 projected, -1.1) 4.68
2014.01 157.4
(cycle peak)
152.4 82.0 (71.0 projected, -0.8) 5.44
2014.02 169.7 (1)   123.6 (2A) / 164.8 (2B) / 107.3 (2C) (71.2 projected, +0.2) (10.8)

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.