Solar Terrestrial Activity Report

Activity chart

Partial update issued on May 19, 2014 at 06:10 UTC. Updates May 18-23 will be irregular and possibly incomplete.

[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 18. Solar wind speed at SOHO ranged between 340 and 358 km/s.

Solar flux at 20h UTC on 2.8 GHz was 127.5 (decreasing 30.3 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 148.8. The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.9). Three hour interval K indices: 11001211 (planetary), 22102312 (Boulder).

The background x-ray flux is at the class B5 level.

At the time of counting spots (see image time), spots were observed in 18 active regions in 2K resolution (SN: 261) and 17 active regions in 1K resolution (SN: 215) SDO images on the visible solar disk.

Region 12057 [N17W80] decayed slowly and quietly.
Region 12060 [S12W61] decayed slowly and quietly.
Region 12061 [S23W22] was quiet and stable.
Region 12063 [N10W10] decayed slowly and quietly.
Region 12064 [N09W26] developed slowly and was quiet.
Region 12065 [S18E26] decayed slowly and quietly.
Region 12066 [S16W25] was mostly quiet but could produce C flares.
Region 12067 [S08W81] decayed slowly and quietly.
Region 12068 [S16E13] decayed slowly and quietly.
New region 12069 [S18E53] emerged on May 17 and was numbered the next day by SWPC.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3417 [S23W22] was quiet and stable.
S3444 [S23E58] was quiet and stable.
S3446 [N00E23] was quiet and stable.
S3448 [S25E07] was quiet and stable.
New region S3449 [N27E57] emerged with a few spots.
New region S3450 [S17W48] emerged with several spots in what used to be the trailing spot section of AR 12060.
New region S3451 [N08W38] emerged with a few spots.
New region S3452 [N17W09] emerged with a penumbra spot.

C2+ Flares (SDO/EVE):

Magnitude Time (UTC) Location AR
C3.5 07:01 N07W90 12056
C3.1 08:32 N06W90 12056

Coronal mass ejections (CMEs)

May 16-18: 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

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 May 19-21.

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
12056 2014.05.05
2014.05.06
6     N04W91 0100 ESI    

rotated out of view

12057 2014.05.06
2014.05.07
1 1 1 N16W81 0010 AXX AXX area: 0004
12058 2014.05.07
2014.05.08
      S11W67           plage
12060 2014.05.08
2014.05.11
2 4 3 S13W62 0140 HAX CAO images/AR_12060_20140516_2345.png

area: 0220

12061 2014.05.10
2014.05.11
1 5 3 S23W22 0080 HSX CSO area: 0150
S3417 2014.05.11   1   S23W32 0002   AXX  
S3418 2014.05.11       N22W17           plage
S3420 2014.05.12       S09W55           plage
S3422 2014.05.13       S23E10           plage
S3423 2014.05.13       S09W19           plage
12063 2014.05.13
2014.05.14
10 10 6 N11W10 0030 CRI CRO

 

12064 2014.05.13
2014.05.14
  5 2 N09W28 0016   CRO  
S3426 2014.05.13       N00W44         plage
S3427 2014.05.13       N18W57           plage
12066 2014.05.13
2014.05.16
7 12 7 S16W26 0070 DAO DAO area: 0130
12065 2014.05.14
2014.05.15
6 12 4 S18E24 0010 BXO BXO  
S3433 2014.05.15       N18W29           plage
S3436 2014.05.15       N08E09           plage
S3437 2014.05.15       N25E29           plage
12067 2014.05.16
2014.05.17
1 1 1 S09W83 0010 BXO AXX area: 0003
12068 2014.05.16
2014.05.17
3 4 2 S18E13 0010 BXO BXO  
S3440 2014.05.16       S12W13         plage
S3441 2014.05.16       N27W24           plage
S3442 2014.05.16       S05W36         plage
S3443 2014.05.16       N10W08         plage
S3444 2014.05.17   1 1 S23E58 0004   AXX  
12069 2014.05.17
2014.05.18
1 3 1 S18E52 0010 AXX CRO  
S3446 2014.05.17   2 1 N00E23 0008   BXO  
S3448 2014.05.17   4 1 S25E07 0010   AXX  
S3449 2014.05.18   3 2 N27E27 0010   CRO    
S3450 2014.05.18   8 6 S17W48 0050   DRI    
S3451 2014.05.18   4 3 N08W38 0020   DRO    
S3452 2014.05.18   1 1 N17W09 0004   AXX    
Total spot count: 38 81 45  
Sunspot number: 138 261 215  (total spot count + 10 * number of spotted regions)
Weighted SN: 61 114 78  (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): 83 91 118 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
2014.05 144.6 (1)   76.4 (2A) / 131.6 (2B) / 104.1 (2C) (74.4 projected, -2.6) (5.9)

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.