Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 9, 2014 at 05:30 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 August 9, 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 8. Solar wind speed at SOHO ranged between 347 and 389 km/s, possibly under the influence of a low speed stream from CH630.

Solar flux at 20h UTC on 2.8 GHz was 123 (decreasing 22.0 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 133.9. The Potsdam WDC planetary A index was 7 (STAR Ap - based on the mean of three hour interval ap indices: 7.4). Three hour interval K indices: 33222101 (planetary), 34322211 (Boulder).

The background x-ray flux is at the class B4 level.

At the time of counting spots (see image time), spots were observed in 9 active regions using 2K resolution (SN: 187) and 8 active regions using 1K resolution (SN: 131) SDO images on the visible solar disk.

Region 12130 [S08W68] decayed slowly and quietly.
Region 12132 [S19W47] decayed slowly and was mostly quiet.
Region 12134 [N09W10] decayed quickly losing all umbrae.
Region 12135 [N12E38] developed slowly and has minor polarity intermixing.
New region 12136 [N08W39] was first observed with spots on August 3. New flux emerged on August 7 witth SWPC numbering the region the next day.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3707 [S18E05] gained penumbra spots.
New region S3718 [S22E19] emerged with penumbra spots.
New region S3719 [N06E07] emerged with a penumbra spot.
New region S3720 [N14E09] emerged with a penumbra spot.

C2+ Flares (GOES):

Magnitude Peak time (UTC) Location AR
C4.5/1N 17:01 N13E44 12135

Coronal mass ejections (CMEs)

August 6-8: 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) was in 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 poor.

Forecast

The geomagnetic field is expected to be quiet on August 9-11.

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
12128 2014.07.27       S19W89         rotated out of view
12130 2014.07.28
2014.07.29
2 2 1 S08W68 0010 AXX AXX  
12131 2014.07.28
2014.07.29
      S19W79           plage
12132 2014.07.30
2014.07.31
18 23 14 S21W47 0230 EAC ESI

location: S19W47

area: 0140

S3690 2014.07.30       N22W49           plage
S3693 2014.07.31       S16W34            
12133 2014.08.01
2014.08.02
      N18W24           plage
S3696 2014.08.01       S04W54         plage
12134 2014.08.01
2014.08.02
17 33 16 N08W11 0070 CAI BXI  
12136 2014.08.03
2014.08.08
4 6 3 N08W43 0010 BXO DRO  
S3703 2014.08.04       N12E09           plage
S3704 2014.08.04       N05W37           plage
S3707 2014.08.05   9 4 S18E05 0015   AXX  
12135 2014.08.06 10 19 11 N11E36 0250 DHO DKO beta-gamma

area: 0550

S3709 2014.08.06       S15W33         plage
S3710 2014.08.06       S20W53           plage
S3712 2014.08.06       S06E16           plage
S3713 2014.08.06       N18W38         plage
S3714 2014.08.07       S19E29         plage
S3715 2014.08.07       S19W01         plage
S3716 2014.08.07       N21W59         plage
S3718 2014.08.08   3 1 S22E19 0008   BXO    
S3719 2014.08.08   1 1 N06E07 0003   AXX    
S3720 2014.08.08   1   N14E09 0001   AXX    
Total spot count: 51 97 51  
Sunspot number: 101 187 131  (total spot count + 10 * number of spotted regions)
Weighted SN: 71 115 69  (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): 61 65 72 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
2014.08 143.8 (1)   31.5 (2A) / 134.6 (2B) / 69.2 (2C) (66.5 projected, -3.4) (7.0)

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.