Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 6, 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 August 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 August 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update August 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 to unsettled on August 5. Solar wind speed at SOHO ranged between 399 and 460 km/s under the influence of a high speed stream from CH629.

Solar flux at 20h UTC on 2.8 GHz was 139 (decreasing 59.4 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 134.5. The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.3). Three hour interval K indices: 22213232 (planetary), 33323332 (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 10 active regions using 2K resolution (SN: 231) and 6 active regions using 1K resolution (SN: 135) SDO images on the visible solar disk.

Region 12127 [S07W46] was quiet and stable.
Region 12128 [S20W46] reemerged with a few spots.
Region 12130 [S07W26] decayed slowly and quietly.
Region 12131 [S18W33] decayed slowly and quietly.
Region 12132 [S19W07 developed a magnetic delta structure in the central spot section. A minor M class flare is possible.
Region 12133 [N18E23] decayed slowly and quietly.
Region 12134 [N10E31] developed a weak magnetic delta structure centrally and could produce C flares.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3696 [S04W14] decayed slowly and quietly.
S3703 [N12E48] decayed slowly and quietly.
New region S3707 [S21E48] emerged with penumbra spots.

C2+ Flares (GOES):

Magnitude Peak time (UTC) Location AR
C2.2 14:18 S19W01 12132
C2.5 20:27   12132

Coronal mass ejections (CMEs)

August 3-5: 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 southern hemisphere coronal hole (CH630) could rotate into an Earth facing position on August 5-6.

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 fair.

Forecast

The geomagnetic field is expected to be quiet on August 6-8.

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
12124 2014.07.25
2014.07.26
      S21W75           plage
12125 2014.07.25
2014.07.26
      S14W67           plage
12127 2014.07.27 8 17 9 S08W47 0030 DRI DRI

area: 0060

12128 2014.07.27   3 1 S21W47 0020   CRO   location: S20W46
12130 2014.07.28
2014.07.29
16 32 16 S07W23 0060 FSO CRI images/AR_12130_20140805_2345.png beta-gamma
12131 2014.07.28
2014.07.29
  5   S19W37 0010   BXO location: S18W33
S3686 2014.07.29       N15W51           plage
12132 2014.07.30
2014.07.31
19 36 25 S21W07 0190 EAI EAC beta-gamma-delta

area: 0400

location: S19W07

S3690 2014.07.30       N22W10           plage
S3693 2014.07.31       S16E05            
12133 2014.08.01
2014.08.02
  2   N18E18 0003   AXX  
S3696 2014.08.01   6 4 S04W14 0015   AXX  
12134 2014.08.01
2014.08.02
10 27 20 N09E29 0160 DSO DAI beta-gamma-delta

location: N10E31

S3700 2014.08.01       S07W25           plage
S3702 2014.08.03       N07W09         plage
S3703 2014.08.04   1   N12E48 0002   AXX  
S3704 2014.08.04       N05E02         plage
S3705 2014.08.04       S20W33         plage
S3706 2014.08.04       N20W40         plage
S3707 2014.08.05   2   S21E48 0004   AXX    
Total spot count: 53 131 75  
Sunspot number: 93 231 135  (total spot count + 10 * number of spotted regions)
Weighted SN: 71 150 94  (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): 56 81 74 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
2013.04 124.8 125.9 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 77.3 (+1.3) 5.44
2014.02 170.3
(cycle peak)
166.3 102.3 (cycle peak) (78.1 projected, +0.8) 10.70
2014.03 149.9 148.5 91.9 (79.0 projected, +0.9) 4.88
2014.04 143.9 144.8 84.7 (78.1 projected, -0.9) 7.88
2014.05 129.7 132.9 75.2 (75.6 projected, -2.5) 5.75
2014.06 122.0 125.8 71.0 (72.9 projected, -2.7) 6.72
2014.07 137.4 141.8 72.5 (69.9 projected, -3.0) 4.5
2014.08 150.8 (1)   22.5 (2A) / 139.8 (2B) / 74.9 (2C) (66.5 projected, -3.4) (7.9)

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.