Solar Terrestrial Activity Report

Activity chart

Last major update issued on February 14, 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 13. Solar wind speed at SOHO ranged between 313 and 397 km/s.

Solar flux at 20h UTC on 2.8 GHz was 166.6 (increasing 37.8 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 149.7. The Potsdam WDC planetary A index was 1 (STAR Ap - based on the mean of three hour interval ap indices: 1.3). Three hour interval K indices: 10010000 (planetary), 00011211 (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 9 active regions in 2K resolution (SN: 289) and 9 active regions in 1K resolution (SN: 192) SDO images on the visible solar disk.

Region 11971 [S12W72] decayed slowly and quietly.
Region 11973 [N05W45] decayed quickly and was quiet.
Region 11974 [S12W32] was quiet and stable. SWPC is counting AR S3098 and this group as one.
Region 11976 [S15E10] was quiet and stable.
Region 11977 [S10E38] developed slowly and could produce C and minor M class flares.
Region 11978 [N05W67] decayed slowly and quietly.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3098 [S12W24] is a large and complex region with major flare potential. The region has become better organized over the last day with spots merging into larger penumbrae, considerable decay was observed in the southeastern section. There are several magnetic delta structures throughout the region with the most complex layout in the northern trailing and central sections. C5+ flares: M1.8 at 01:40, C5.4 at 02:18, C7.4 at 02:29, M1.0 at 02:51, M1.7 at 06:07, M1.0/1N at 08:12, C8.4 at 10:48, M1.4 at 15:57, C6.6 at 19:55 UTC.
S3105 [S14E21] was quiet and stable.
S3118 [N07W62] decayed slowly and quietly.

Coronal mass ejections (CMEs)

February 13: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
February 12: A slow symmetric full halo CME was observed after an M2 flare in AR S3098. The CME could reach Earth on February 15.
February 11
: A partial halo CME was observed after 11h UTC following a filament eruption near AR 11978 in the northwest quadrant. It is uncertain if the CME has any Earth directed components.

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

Forecast

The geomagnetic field is expected to be quiet on February 14. Quiet to active conditions with a chance of minor storm intervals is possible on February 15-16 due to CME effects.

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
S3082 2014.02.01       N08W56           plage
11971 2014.02.03
2014.02.04
3 2 2 S11W72 0040 CSO CRO

 

S3092 2014.02.04       S08W58           plage
11973 2014.02.04
2014.02.05
4 4 2 N16W43 0030 CSO CAO

SWPC location must be a typo

real location: N05W45

11974 2014.02.04
2014.02.05
47 4 3 S07W25 0780 FKC CAO location: S12W32

area: 0150

S3096 2014.02.05       N15W40           plage
S3098 2014.02.06   104 55 S12W24 1220   EKC gamma-delta

SWPC has this as part of AR 11974

11976 2014.02.07
2014.02.08
15 31 14 S15E13 0370 FKI DHO area: 0370

(SWPC area includes AR S3105)

location: S15E23

S3102 2014.02.08       S19W35         plage
S3105 2014.02.09   4 3 S14E21 0190   CSO SWPC has this as part of AR 11976
S3106 2014.02.09       N26W53           plage
11977 2014.02.10 16 41 18 S09E38 0460 EKC EKC area: 0580
11978 2014.02.10
2014.02.11
12 7 4 N07W66 0030 DAO BXO location: N05W67
S3110 2014.02.10       S37W46           plage
S3111 2014.02.11       N17W30           plage
S3112 2014.02.11       S32E22           plage
S3113 2014.02.11       N17W23           plage
S3114 2014.02.11       N30W36           plage
11979 2014.02.11
2014.02.12
      N13W54         plage
S3118 2014.02.12   2 1 N07W62 0010   CRO  
S3120 2014.02.12       S25W17         plage
S3121 2014.02.12       S21W55         plage
Total spot count: 97 199 102  
Sunspot number: 157 289 192  (total spot count + 10 * number of spotted regions)
Weighted SN: 142 250 153  (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): 94 101 106 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
2014.02 177.4 (1)   83.6 (2A) / 180.2 (2B) / 107.9 (2C) (71.2 projected, +0.2) (7.4)

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 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.