Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 13, 2014 at 03:10 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 August 13, 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 12. Solar wind speed at SOHO ranged between 384 and 506 km/s, likely under the influence of a high speed stream from CH631 late in the day.

Solar flux at 20h UTC on 2.8 GHz was 104 (increasing 11.9 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 131.4. The Potsdam WDC planetary A index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 9.1). Three hour interval K indices: 32111233 (planetary), 22112433 (Boulder).

The background x-ray flux is at the class B3 level.

At the time of counting spots (see image time), spots were observed in 7 active regions using 2K resolution (SN: 149) and 6 active regions using 1K resolution (SN: 97) SDO images on the visible solar disk.

Region 12135 [N15W22] decayed further losing all trailing umbrae.
Region 12137 [S18W48] decayed slowly and quietly.
Region 12138 [N13W82] decayed slowly and quietly.
Region 12139 [N14E57] developed gaining many small spots.
New region 12140 [N13W52] emerged on August 8 and was numbered by SWPC 4 days later.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3728 [S16E08] developed slowly and quietly.
New region S3729 [N02W28] emerged with a penumbra spot.

C2+ Flares (GOES):

Magnitude Peak time (UTC) Location AR
       

Coronal mass ejections (CMEs)

August 10-12: 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 trans equatorial coronal hole (CH631) was in an Earth facing position on August 9-10.

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 to unsettled on August 13 and quiet on August 14-15.

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
12133 2014.08.01
2014.08.02
      N18W80           plage
12134 2014.08.01
2014.08.02
      N08W65         plage
S3703 2014.08.04       N12W43           plage
12137 2014.08.05
2014.08.09
5 7 4 S18W51 0010 DRO CRO location: S18W48

area: 0020

12135 2014.08.06 6 11 5 N12W19 0170 EAO CSO

area: 0210

S3712 2014.08.06       S06W36           plage
S3714 2014.08.07       S19W23           plage
S3715 2014.08.07       S19W53           plage
S3718 2014.08.08       S26W36           plage
S3719 2014.08.08       N06W45           plage
12140 2014.08.08
2014.08.12
4 10 4 N13W53 0010 BXO CRO area: 0040
12139 2014.08.10
2014.08.11
13 46 21 N14E55 0120 DSO ESI  
S3723 2014.08.10       S23W16         plage
12138 2014.08.11 2 1 1 N13W84 0030 CSO HRX area: 0010
S3727 2014.08.11       N06E06         plage
S3728 2014.08.11   3 2 S16E08 0008   BXO  
S3729 2014.08.12   1   N02W28 0002   AXX    
Total spot count: 30 79 37  
Sunspot number: 80 149 97  (total spot count + 10 * number of spotted regions)
Weighted SN: 48 98 56  (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): 48 52 53 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
2014.08 131.7 (1)   45.6 (2A) / 117.8 (2B) / 64.5 (2C) (66.5 projected, -3.4) (6.9)

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.