Solar Terrestrial Activity Report

Activity chart

Last major update issued on May 14, 2014 at 04:50 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 13. Solar wind speed at SOHO ranged between 333 and 447 km/s.

Solar flux at 20h UTC on 2.8 GHz was 159.4 (decreasing 13.7 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 149.4. The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.8). Three hour interval K indices: 11110002 (planetary), 11113312 (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: 380) and 17 active regions in 1K resolution (SN: 283) SDO images on the visible solar disk.

Region 12055 [N11W37] decayed slowly and quietly.
Region 12056 [N05W23] decayed slowly. A minor M class flare is still possible.
Region 12057 [N14W12] was quiet and stable.
Region 12058 [S12E02] gained penumbra spots and was quiet.
Region 12060 [S16E09] developed slowly and was mostly quiet. The region has M class flare potential.
Region 12061 [S24E43] was quiet and stable.
Region 12062 [S07W57] decayed slowly and quietly.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3405 [N08W18] was quiet and stable.
S3411 [S17W17] was quiet and stable.
S3417 [S26E28] reemerged with penumbra spots.
New region S3422 [S22E58] emerged with a penumbra spot.
New region S3423 [S09E59] emerged with a penumbra spot.
New region S3424 [N10E57] emerged rapidly with several spots and could produce C flares.
New region S3425 [N08E41] emerged with a few spots.
New region S3426 [S01E24] emerged with penumbra spots.
New region S3427 [N16E11] emerged with penumbra spots.
New region S3428 [S18W38] emerged with a penumbra spot.
New region S3429 [S17E43] emerged with narrowly spaced penumbra spots.

C2+ Flares (SDO/EVE):

Magnitude Time (UTC) Location AR
C6.3 22:30 N06W21 12056

Coronal mass ejections (CMEs)

May 11-13: 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 trans equatorial coronal hole (CH617) was in an Earth facing position on May 12-13.

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.

Forecast

The geomagnetic field is expected to be quiet on May 14 and quiet to active on May 15-16 due to effects from CH617.

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
12053 2014.05.03       N09W83        

plage

12054 2014.05.03
2014.05.04
      S09W59         plage
12055 2014.05.04
2014.05.05
16 32 13 N12W36 0280 EHO EHI area: 0400
12056 2014.05.05
2014.05.06
11 31 21 N05W23 0190 ESC EAI

area: 0280

12057 2014.05.06
2014.05.07
2 8 4 N14W12 0080 HAX CAO area: 0170
S3397 2014.05.06       S15W14           plage
S3401 2014.05.07       N03W09           plage
12058 2014.05.07
2014.05.08
9 23 13 S10W00 0010 AXX CRI

area: 0040

S3404 2014.05.08       N13W48           plage
S3405 2014.05.08   4 3 N08W18 0003   BXO  
12059 2014.05.08
2014.05.10
      S01W21        

 

12060 2014.05.08
2014.05.11
21 51 29 S15E08 0170 DAC DAC beta-gamma

area: 0420

S3410 2014.05.09       S17W37           plage
S3411 2014.05.10   3 2 S17W17 0008   AXX  
12061 2014.05.10
2014.05.11
1 8 4 S25E40 0090 HSX CAO area: 0160
12062 2014.05.10
2014.05.11
8 11 5 S05W57 0060 DAO DAO  
S3415 2014.05.10       N01W10          
S3417 2014.05.11   3 2 S26E28 0010   AXX    
S3418 2014.05.11       N22E48           plage
S3420 2014.05.12       S09E10         plage
S3422 2014.05.13   1 1 S22E58 0003   AXX    
S3423 2014.05.13   1 1 S09E59 0003   AXX    
S3424 2014.05.13   12 9 N10E57 0160   DAI   beta-gamma
S3425 2014.05.13   5 3 N08E41 0020   CRO    
S3426 2014.05.13   2 1 S01E24 0004   BXO    
S3427 2014.05.13   2 1 N16E11 0004   BXO    
S3428 2014.05.13   1   S18W38     AXX    
S3429 2014.05.13   2 1 S17E43     AXX    
Total spot count: 68 200 113  
Sunspot number: 138 380 283  (total spot count + 10 * number of spotted regions)
Weighted SN: 103 246 159  (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): 83 133 156 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
2014.05 145.2 (1)   53.5 (2A) / 127.5 (2B) / 106.5 (2C) (74.4 projected, -2.6) (6.8)

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.