Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 31, 2014 at 04:55 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 30. Solar wind speed at SOHO ranged between 367 and 433 km/s under the influence of effects from CH632.

Solar flux at 20h UTC on 2.8 GHz was 123 (decreasing 29 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 132.3. The Potsdam WDC planetary A index was 12 (STAR Ap - based on the mean of three hour interval ap indices: 11.6). Three hour interval K indices: 33233222 (planetary), 34234322 (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 11 active regions using 2K resolution (SN: 188) and 10 active regions using 1K resolution (SN: 138) SDO images on the visible solar disk.

Region 12149 [N09W49] lost some spots and no longer has a magnetic delta structure. There is still polarity intermixing and a minor M class flare is possible.
Region 12150 [S13W32] was quiet and stable.
Region 12151 [S07W19] was quiet and stable.
Region 12152 [S15E28] developed significantly. The region has polarity intermixing and could produce an M class flare.
Region 12153 [S11E02] decayed slowly and quietly.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3773 [S26W43] decayed slowly and quietly.
S3774 [N06E14] was quiet and stable.
S3775 [N06W43] was quiet and stable.
New region S3778 [S13W03] was observed with penumbra spots.
New region S3779 [N10E37] emerged with a penumbra spot.
New region S3780 [N15E04] was observed with a penumbra spot.

C2+ Flares (GOES):

Magnitude Peak time (UTC) Location AR
C2.0 04:28 N08W38 12149
C3.3 04:56   12149
C2.0 10:19 N05W41 12149
C2.8 14:25 S14E35 12152

Coronal mass ejections (CMEs)

August 28-30: 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]

No obvious coronal holes are currently in or near Earth facing positions.

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 unsetted on August 31 under the influence of effects from CH632 and quiet on September 1-2.

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
12149 2014.08.21 11 22 8 N09W50 0280 DHC DKI

beta-gamma

area: 0380

12150 2014.08.22 1 3 2 S14W32 0090 HSX CAO area: 0120
12151 2014.08.22
2014.08.23
1 9 3 S07W21 0120 HSX CAO area: 0200
S3763 2014.08.25       N13W58           plage
S3764 2014.08.25       N03W26           plage
S3765 2014.08.26       N13E02           plage
12153 2014.08.26
2014.08.29
  1 1 S10E03 0005   AXX  
12152 2014.08.26
2014.08.28
11 34 19 S17E27 0070 DAI DAI location: S15E28

area: 0260

S3768 2014.08.26       N18W24           plage
S3769 2014.08.26       S14W51           plage
S3772 2014.08.29       S07E15         plage
S3773 2014.08.29   1   S26W43 0003   AXX  
S3774 2014.08.29   3 1 N06E14 0008   AXX  
S3775 2014.08.29   1 1 N06W43 0003   AXX  
S3778 2014.08.30   2 1 S13W03 0006   AXX    
S3779 2014.08.30   1 1 N10E37 0003   AXX    
S3780 2014.08.30   1 1 N06E14 0006   AXX    
Total spot count: 24 78 38  
Sunspot number: 64 188 138  (total spot count + 10 * number of spotted regions)
Weighted SN: 49 103 63  (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): 44 66 76 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) 4.50
2014.08 124.6 (1)   103.3 (2A) / 106.8 (2B) / 75.4 (2C) (66.5 projected, -3.4) (7.6)

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.