Solar Terrestrial Activity Report

Activity chart

Last major update issued on May 8, 2014 at 05:00 UTC.

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

[POES auroral activity level October 2009 - December 2012]
[Solar polar fields vs solar cycles - updated April 17, 2014]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was quiet on May 7. Solar wind speed at SOHO ranged between 324 and 390 km/s. A weak disturbance began late in the day.

Solar flux at 20h UTC on 2.8 GHz was 145.9 (increasing 9.2 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 149.7. The Potsdam WDC planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 2.3). Three hour interval K indices: 00001012 (planetary), 10012413 (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: 226) and 12 active regions in 1K resolution (SN: 157) SDO images on the visible solar disk.

Region 12049 [S09W63] decayed slowly and quietly.
Region 12050 [N12W58] was quiet and stable.
Region 12052 [S12W18] was quiet and stable.
Region 12053 [N09W01] decayed slowly and quietly.
Region 12054 [S12E26] decayed slowly and quietly.
Region 12055 [N11E44] was mostly unchanged and quiet. An M class flare is possible.
Region 12056 [N05E58] has a magnetic delta structure in the trailing penumbra. An M class flare is possible. The northernmost and southernmost spots are being considered for a split.
New region 12057 [N15E67] rotated into view on May 6 and was numbered by SWPC the next day.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3386 [S16W16] reemerged with a penumbra spot.
S3393 [S12W55] was quiet and stable.
S3394 [S15E17] was quiet and stable.
New region S3401 [N03E68] rotated into view with a penumbra spot.
New region S3402 [S12E80] rotated into view.
New region S3403 [N14E19] emerged with a penumbra spot.

C2+ Flares (SDO/EVE):

Magnitude Time (UTC) Location AR
C3.4 06:32 S12W90 12051
C2.7 12:41 N04E67 12056
M1.0 16:24 S13W90 12051
C3.3 19:23 S12W90 12051
C2.2 21:26 N04E62 12056

Coronal mass ejections (CMEs)

May 5-7: 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 small southern hemisphere coronal hole (CH615) was in an Earth facing position on May 4. A small southern hemisphere coronal hole (CH616) was in an Earth facing position on May 7.

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 unsettled on May 8-10.

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: 0-30% probability, Yellow: 30-70% probability, Red: 70-100% 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 Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
12049 2014.04.26
2014.04.27
1 5 2 S07W62 0170 HSX CAO

area: 0240

location: S09W63

12050 2014.04.27 1 1 1 N12W61 0010 HRX HRX location: N12W58
12052 2014.05.01
2014.05.02
2 8 4 S12W20 0010 HRX CRO location: S12W18
S3379 2014.05.01       S06W08           plage
S3380 2014.05.02       N10W05           plage
S3382 2014.05.02       S14W35           plage
12053 2014.05.03 5 12 6 N10W02 0030 CRO DRO

 

12054 2014.05.03
2014.05.04
1 12 3 S12E23 0020 HRX CRO location: S12E26
S3385 2014.05.03       N10E19           plage
S3386 2014.05.03   1   S16W16 0003   AXX    
12055 2014.05.04
2014.05.05
5 15 7 N11E39 0380 DKO EKO area: 0780

location: N11E44

S3389 2014.05.04       S32W01           plage
S3390 2014.05.04       N12W57           plage
12056 2014.05.05
2014.05.06
9 22 9 N04E56 0310 DKO EKC beta-delta

location: N05E58

area: 0580

S3393 2014.05.05   3 1 S12W55 0006   AXX  
S3394 2014.05.05   1   S15E17 0003   AXX  
S3395 2014.05.05       S12E16           plage
12057 2014.05.06
2014.05.07
1 3 1 N15E67 0080 HSX HSX  
S3397 2014.05.06       S15E77         plage
S3398 2014.05.06       S26E03         plage
S3399 2014.05.06       S02W45         plage
S3400 2014.05.06       S24W33         plage
S3401 2014.05.07   1 1 N03E56     AXX    
S3402 2014.05.07   1 1 S12E80 0100   HSX    
S3403 2014.05.07   1 1 N14E19     AXX    
Total spot count: 25 86 37  
Sunspot number: 105 226 157  (total spot count + 10 * number of spotted regions)
Weighted SN: 64 133 84  (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): 63 79 86 k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for MSN 2K, k = 0.55 for MSN 1K (MSN=Magnetic Sunspot Number)

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number Average ap
(3)
Measured 1 AU
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 (+3.5) 8.27
2013.09 102.6 103.7 36.9 73.1 (+4.1) 5.23
2013.10  132.1 131.2 85.6 75.0 (+1.9) 7.71
2013.11  148.3 145.1 77.6 (75.6 projected, +0.6) 5.68
2013.12 147.7 143.1 90.3 (76.6 projected, +1.0) 4.68
2014.01 157.4 152.4 82.0 (77.6 projected, +1.0) 5.44
2014.02 170.3
(cycle peak)
166.3 102.8 (cycle peak) (77.4 projected, -0.2) 10.70
2014.03 149.9 148.5 92.2 (77.9 projected, +0.5) 4.88
2014.04 143.9 144.8 84.7 (77.0 projected, -0.9) 7.88
2014.05 136.4 (1)   30.5 (2A) / 118.3 (2B) / 95.4 (2C) (74.4 projected, -2.6) (6.9)

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.