Solar Terrestrial Activity Report

Activity chart

Last major update issued on May 17, 2014 at 06:20 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 16. Solar wind speed at SOHO ranged between 336 and 429 km/s.

Solar flux at 20h UTC on 2.8 GHz was 138.7 (decreasing 30.6 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 149.3. The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 5.4). Three hour interval K indices: 22112221 (planetary), 12112311 (Boulder).

The background x-ray flux is at the class B6 level.

At the time of counting spots (see image time), spots were observed in 18 active regions in 2K resolution (SN: 324) and 15 active regions in 1K resolution (SN: 230) SDO images on the visible solar disk.

Region 12055 [N12W80] decayed slowly and quietly.
Region 12056 [N05W66] produced a few C flares and decayed slowly.
Region 12057 [N16W53] decayed slowly and quietly.
Region 12060 [S13W33] decayed slowly and quietly.
Region 12061 [S23E04] decayed slowly and quietly.
Region 12063 [N10E17] gained spots as the main penumbrae split into smaller penumbrae.
Region 12064 [N09E01] decayed slowly and quietly.
Region 12065 [S19E53] was quiet and stable.
New region 12066 [S15E02] emerged on May 13, was spotless the next day and reemerged on May 15. Further development occurred on May 16 when the region was numbered by SWPC.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3422 [S23E36] was quiet and stable.
S3426 [N00W10] was quiet and stable.
S3429 [S16E16] reemerged with a penumbra spot.
S3433 [N18W03] was quiet and stable.
New region S3438 [S07W55] emerged with a few spots.
New region S3439 [S17E40] emerged with several spots.
New region S3440 [S12W00] emerged with several penumbra spots to the northwest of AR 12066.
New region S3441 [N27E02] emerged with a penumbra spot.
New region S3442 [S08W16] emerged with a penumbra spot.
New region S3443 [N20E36] emerged with a penumbra spot.

C2+ Flares (SDO/EVE):

Magnitude Time (UTC) Location AR
C4.5 07:04 N05W56 12056
C2.8 07:14 N04W56 12056
C2.0 20:20 N09E20 12063

Coronal mass ejections (CMEs)

May 14-16: 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 17-19.

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
12055 2014.05.04
2014.05.05
3 3 1 N13W77 0150 CSO CHO area: 0310
12056 2014.05.05
2014.05.06
7 13 7 N06W63 0140 ESI ESO

beta-gamma

area: 0240

location: N05W66

12057 2014.05.06
2014.05.07
1 3 2 N16W54 0060 HAX HAX  
S3401 2014.05.07       N03W48           plage
12058 2014.05.07
2014.05.08
      S11W40         plage
12059 2014.05.08
2014.05.10
      S01W66          

plage

12060 2014.05.08
2014.05.11
11 24 13 S14W32 0150 CAO CKO images/AR_12060_20140516_2345.png images/AR_12060_20140515_2330.png beta-gamma

area: 0300

12061 2014.05.10
2014.05.11
2 11 6 S23E04 0110 HAX CSO area: 0170
S3415 2014.05.10       N01W49           plage
S3417 2014.05.11       S22W03           plage
S3418 2014.05.11       N22E09           plage
S3420 2014.05.12       S09W29           plage
S3422 2014.05.13   2   S21E39 0003   AXX      
S3422 2014.05.13   5 1 S23E36     AXX  
S3423 2014.05.13       S09E07           plage
12063 2014.05.13
2014.05.14
11 32 20 N10E17 0120 DAI DAI

 

12064 2014.05.13
2014.05.14
3 8 7 N09W00 0010 BXO BXO  
S3426 2014.05.13   2 1 N00W18 0008   BXO  
S3427 2014.05.13       N18W30           plage
12066 2014.05.13
2014.05.16
5 11 5 S16E01 0020 CAO DRI area: 0040
12065 2014.05.14
2014.05.15
3 9 1 S19E53 0010 CRO CRO  
S3432 2014.05.14       S12W55           plage
S3433 2014.05.15   1   N18W03 0001   AXX  
S3434 2014.05.15       N23W40         plage
S3435 2014.05.15       S23W53         plage
S3436 2014.05.15       N08E35         plage
S3437 2014.05.15       N25E55         plage
S3437 2014.05.15       N25E55         plage
S3438 2014.05.16   4 3 S07W55 0025   DRO    
S3439 2014.05.16   7 6 S17E40 0035   DRO    
S3440 2014.05.16   8 6 S12W00 0020   BXI    
S3441 2014.05.16   1 1 N27E02 0060   AXX    
S3442 2014.05.16   1 1 S08W16 0002   AXX    
S3443 2014.05.16   1 1 N10E17 0001   AXX    
Total spot count: 46 144 80  
Sunspot number: 136 324 230  (total spot count + 10 * number of spotted regions)
Weighted SN: 84 196 132  (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): 82 113 127 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
2014.05 146.4 (1)   67.3 (2A) / 130.3 (2B) / 105.7 (2C) (74.4 projected, -2.6) (6.3)

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.