Solar Terrestrial Activity Report

Activity chart

Last major update issued on May 15, 2014 at 05:10 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 14. Solar wind speed at SOHO ranged between 316 and 378 km/s.

Solar flux at 20h UTC on 2.8 GHz was 163.2 (decreasing 15.7 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: 3.6). Three hour interval K indices: 11002101 (planetary), 21012322 (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 16 active regions in 2K resolution (SN: 347) and 13 active regions in 1K resolution (SN: 237) SDO images on the visible solar disk.

Region 12055 [N11W51] decayed slowly and quietly.
Region 12056 [N05W37] developed slowly and has polarity intermixing. A minor M class flare is possible.
Region 12057 [N14W25] was quiet and stable.
Region 12058 [S11W12] was quiet and stable.
Region 12060 [S16W05] has polarity intermixing and minor M class flare potential.
Region 12061 [S24E29] was quiet and stable.
Region 12062 [S07W71] was quiet and stable.
New region 12063 [N09E43] emerged on May 13 and developed quickly on May 14 when it was numbered by SWPC. M class flaring is possible.
New region 12064 [N08E28] emerged on May 13 with slow development continuing on May 14.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3405 [N08W33] was quiet and stable.
S3411 [S13W38] was quiet and stable.
S3417 [S22E23] was quiet and stable.
S3426 [S01E09] emerged with penumbra spots.
S3427 [N18W04] was quiet and stable.
New region S3431 [S19E80] rotated into view.
New region S3432 [S12W29] emerged with a penumbra spot.

C2+ Flares (SDO/EVE):

Magnitude Time (UTC) Location AR
C2.3 00:53 N10E60 12063
C2.3 08:59 N09E54 12063
C3.2 13:20 N07W27 12056
C8.4 15:04 N07W34 12056
C4.6 15:48 N07W35 12056

Coronal mass ejections (CMEs)

May 12-15: 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 to unnsettled on May 15-16 due to effects from CH617 and quiet on May 17.

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
12054 2014.05.03
2014.05.04
      S09W73           plage
12055 2014.05.04
2014.05.05
9 20 10 N12W50 0250 EHO EHI area: 0390
12056 2014.05.05
2014.05.06
13 34 17 N05W37 0210 EAI ESC

beta-gamma

area: 0290

12057 2014.05.06
2014.05.07
4 12 6 N15W27 0090 CAO CAO area: 0130
S3397 2014.05.06       S15W27           plage
S3401 2014.05.07       N03W22           plage
12058 2014.05.07
2014.05.08
9 14 10 S11W12 0010 BXO BXO

area: 0050

S3405 2014.05.08   1   N08W33          
12059 2014.05.08
2014.05.10
      S01W36          

plage

12060 2014.05.08
2014.05.11
23 40 31 S16W05 0170 DAC DAC beta-gamma

area: 0340

S3410 2014.05.09       S17W50           plage
S3411 2014.05.10   3   S13W38 0005   AXX  
12061 2014.05.10
2014.05.11
1 5 3 S23E27 0090 HAX CAO area: 0160
12062 2014.05.10
2014.05.11
4 5 2 S06W72 0040 CAO CRO  
S3415 2014.05.10       N01W23           plage
S3417 2014.05.11   3   S22E23 0006   AXX  
S3418 2014.05.11       N22E35           plage
S3420 2014.05.12       S09W03           plage
S3422 2014.05.13       S22E45         plage
S3423 2014.05.13       S09E46         plage
12063 2014.05.13
2014.05.14
5 24 14 N09E43 0120 DAO DAC beta-gamma-delta

area: 0260

12064 2014.05.13
2014.05.14
4 14 6 N08E28 0010 BXO DRO area: 0040
S3426 2014.05.13   8 5 S01E09 0025   CRO  
S3427 2014.05.13   2 1 N18W04 0005   BXO  
S3428 2014.05.13       S18W51         plage
S3429 2014.05.13       S17E30          
S3431 2014.05.14   1 1 S19E80 0005   AXX    
S3432 2014.05.14   1 1 S12W29 0005   AXX    
Total spot count: 72 187 107  
Sunspot number: 162 347 237  (total spot count + 10 * number of spotted regions)
Weighted SN: 112 231 151  (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): 97 121 130 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
2014.05 146.5 (1)   58.7 (2A) / 129.9 (2B) / 107.2 (2C) (74.4 projected, -2.6) (6.5)

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.