Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 31, 2014 at 04:45 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update July 1, 2014)] [Cycle 24 progress (last update July 1, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update July 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update July 1, 2014)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update July 5, 2014)]

[POES auroral activity level October 2009 - December 2012]
[Solar polar fields vs solar cycles - updated July 18, 2014]
[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]

Recent activity

The geomagnetic field was quiet on July 30. Solar wind speed at SOHO ranged between 283 and 336 km/s.

Solar flux at 20h UTC on 2.8 GHz was 152 (decreasing 26.1 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 133.3. The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.3). Three hour interval K indices: 21110001 (planetary), 22012322 (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 13 active regions using 2K resolution (SN: 281) and 11 active regions using 1K resolution (SN: 182) SDO images on the visible solar disk.

Region 12121 [N07W38] was quiet and stable.
Region 12124 [S23E14] was quiet and stable.
Region 12125 [S13E17] developed slowly and gained spots.
Region 12126 [S10W42] was quiet and stable.
Region 12127 [S08E35] has a weak magnetic delta structure and could produce a minor M class flare.
Region 12128 [S21E35] was quiet and stable.
Region 12129 [S05W34] decayed slowly and quietly.
Region 12130 [S07E56] has a magnetic delta structure in the southernmost penumbra. An M class flare is possible.
Region 12131 [S19E47] developed slowly and quietly.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3680 [N13E01] reemerged with penumbra spots.
S3686 [N12E21] gained a few spots and was quiet.
New region S3689 [S19E74] emerged with penumbra spots.
New region S3690 [N22E58] emerged with a penumbra spot.

C2+ Flares (GOES):

Magnitude Peak time (UTC) Location AR
C3.7 02:46   12130
C9.0 16:17   12127
C3.6 18:48 S08E42 12127

Coronal mass ejections (CMEs)

July 28-29: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
July 30: A filament eruption in the northeast quadrant after 05h UTC was associated with a partial halo CME. This CME could reach Earth on August 2.

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 recurrent trans equatorial coronal hole (CH629) will likely rotate into an Earth facing position on July 31-August 1.

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 July 31 - August 1. A CME could cause unsettled and active intervals on August 2. Weak effects from CH629 could cause a few unsettled intervals on August 3-4.

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
12121 2014.07.21
2014.07.22
10 22 12 N08W39 0100 CAO CAO

location: N07W38

12122 2014.07.21
2014.07.22
      S13W61          

plage

location: S12W52

12123 2014.07.22
2014.07.23
2     S14W38 0010 AXX     spotless
12126 2014.07.24
2014.07.26
16 28 13 S09W41 0120 DAI DAI

area: 0180

12124 2014.07.25
2014.07.26
  2 2 S21E09 0006   BXO  
12125 2014.07.25
2014.07.26
1 14 5 S14E16 0020 HAX CAO area: 0040
S3672 2014.07.26       N20W55           plage
S3673 2014.07.26       S14E01           plage
12127 2014.07.27 12 27 11 S09E36 0300 DKC DKC

beta-gamma-delta

12128 2014.07.27 1 4 1 S20E33 0030 HAX CAO  
12129 2014.07.27
2014.07.28
2 2 1 S05W36 0010 AXX AXX  
S3677 2014.07.27       N02W57           plage
S3678 2014.07.27       S32W50           plage
S3680 2014.07.28   5 3 N13E01 0010   AXX    
12130 2014.07.28
2014.07.29
7 26 16 S08E56 0290 DKC DAC  
12131 2014.07.28
2014.07.29
4 11 5 S19E47 0020 DRO DRI area: 0060
S3683 2014.07.28       S16W14           plage
S3685 2014.07.29       S19W44         plage
S3686 2014.07.29   7 3 N12E21 0015   BXO  
S3687 2014.07.29       N16W35         plage
S3689 2014.07.30   2   S19E74 0003   BXO    
S3690 2014.07.30   1   N22E68 0004   AXX    
Total spot count: 55 151 72  
Sunspot number: 145 281 182  (total spot count + 10 * number of spotted regions)
Weighted SN: 98 189 110  (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): 87 98 100 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 75.4 (+0.4) 5.68
2013.12 147.7 143.1 90.3 76.0 (+0.6) 4.68
2014.01 157.4 152.4 81.8 (78.2 projected, +2.2) 5.44
2014.02 170.3
(cycle peak)
166.3 102.3 (cycle peak) (79.7 projected, +1.5) 10.70
2014.03 149.9 148.5 91.9 (80.5 projected, +0.8) 4.88
2014.04 143.9 144.8 84.7 (79.7 projected, -0.8) 7.88
2014.05 129.7 132.9 75.2 (77.1 projected, -2.6) 5.75
2014.06 122.0 125.8 71.0 (74.5 projected, -2.6) 6.72
2014.07 136.8 (1)   109.6 (2A) / 1123.3 (2B) / 84.7 (2C) (71.5 projected, -3.0) (4.5)

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.