Solar Terrestrial Activity Report

Activity chart

Last major update issued on May 7, 2014 at 04:30 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 very quiet on May 6. Solar wind speed at SOHO ranged between 344 and 416 km/s.

Solar flux at 20h UTC on 2.8 GHz was 138.9 (increasing 8.0 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 150.1. The Potsdam WDC planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 2.5). Three hour interval K indices: 01110010 (planetary), 12121311 (Boulder).

The background x-ray flux is at the class B8 level.

At the time of counting spots (see image time), spots were observed in 15 active regions in 2K resolution (SN: 238) and 14 active regions in 1K resolution (SN: 189) SDO images on the visible solar disk.

Region 12047 [S17W83] decayed slowly and quietly.
Region 12049 [S09W50] decayed slowly and quietly.
Region 12050 [N12W45] decayed slowly and quietly.
Region 12052 [S11W05] decayed slowly and quietly.
Region 12053 [N10E13] decayed losing spots and penumbral area.
Region 12054 [S12E39] gained trailing penumbra spots.
Region 12055 [N12E57] was mostly quiet but has the potential to produce a major flare.
New region 12056 [N05E72] rotated partly into view on May 5 and was numbered the next day by SWPC. The large trailing penumbra could have a magnetic delta structure. An M class flare is possible.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3393 [S17W40] emerged with penumbra spots.
S3394 [S14E35] was quiet and stable.
New region S3396 [N15E79] rotated into view.
New region S3397 [S15E77] rotated into view with a single spot.
New region S3398 [S24E18] emerged with a penumbra spot.
New region S3399 [S02W32] emerged with a penumbra spot.
New region S3400 [S24W20] emerged with a penumbra spot.

C2+ Flares (SDO/EVE):

Magnitude Time (UTC) Location AR
C6.7 04:32 S12W90 12051
M1.9 09:01 S12W90 12051
C5.0 17:34 S10W90 12051
C8.9 22:09 S13W90 12051
C5.8 22:54 N03E90 12056

Coronal mass ejections (CMEs)

May 4-6: 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) could rotate into 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.

Forecast

The geomagnetic field is expected to be quiet on May 7-9 with a chance of unsettled intervals on May 7-8 should a stream from CH615 arrive.

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
12047 2014.04.26 2 3 2 S17W82 0150 CAO CAO

area: 0090

12049 2014.04.26
2014.04.27
9 9 6 S07W48 0180 CAO CSO

area: 0250

location: S09W50

12050 2014.04.27 1 1 1 N12W47 0010 HRX HRX location: N12W45
12051 2014.05.01 10     S09W92 0170 DAC     rotated out of view
12052 2014.05.01
2014.05.02
5 8 5 S12W06 0030 CRO CRO location: S11W05
S3379 2014.05.01       S06E05           plage
S3380 2014.05.02       N10E08           plage
S3381 2014.05.02       S18W50           plage
S3382 2014.05.02       S14W22           plage
12053 2014.05.03 8 20 9 N10E12 0060 DAO DRI

 

12054 2014.05.03
2014.05.04
1 4 4 S12E37 0030 HAX CAO location: S12E39
S3385 2014.05.03       N10E32           plage
S3386 2014.05.03       S18E12         plage
12055 2014.05.04
2014.05.05
7 22 10 N10E53 0230 DSO DKO area: 0650

location: N12E56

S3389 2014.05.04       S32E12           plage
S3390 2014.05.04       N12W44           plage
12056 2014.05.05
2014.05.06
4 11 5 N05E70 0270 DKO EKC beta-delta?

location: N05E72

area: 0520

S3393 2014.05.05   1 1 S17W40 0006   AXX  
S3394 2014.05.05   4 2 S14E35 0009   BXO  
S3395 2014.05.05       S12E29         plage
S3396 2014.05.06   1 1 N15E79 0170   HSX    
S3397 2014.05.06   1 1 S15E77 0005   AXX    
S3398 2014.05.06   1 1 S24E18 0003   AXX    
S3399 2014.05.06   1 1 S02W32 0003   AXX    
S3400 2014.05.06   1   S24W20 0003   AXX    
Total spot count: 47 88 49  
Sunspot number: 137 238 189  (total spot count + 10 * number of spotted regions)
Weighted SN: 93 137 98  (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 83 104 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
2014.05 133.9 (1)   23.1 (2A) / 119.5 (2B) / 95.1 (2C) (74.4 projected, -2.6) (5.8)

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.