Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 7, 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 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 August 6. Solar wind speed at SOHO ranged between 363 and 450 km/s.

Solar flux at 20h UTC on 2.8 GHz was 137 (decreasing 40.4 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 134.4. The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 5.3). Three hour interval K indices: 22211111 (planetary), 23423211 (Boulder).

The background x-ray flux is at the class B5 level.

At the time of counting spots (see image time), spots were observed in 14 active regions using 2K resolution (SN: 291) and 11 active regions using 1K resolution (SN: 176) SDO images on the visible solar disk.

Region 12127 [S08W58] decayed slowly and quietly.
Region 12128 [S20W60] developed slowly and was quiet.
Region 12130 [S07W38] decayed slowly and quietly.
Region 12132 [S19W18] lost the magnetic delta structure and was mostly quiet.
Region 12134 [N10E18] was quiet and stable.
New region 12135 [N11E64] emerged quickly with a few spots.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3696 [S04W27] was quiet and stable.
S3702 [N07W18] reemerged with penumbra spots.
S3707 [S21E35] developed slowly and quietly.
New region S3709 [S15E02] emerged with a penumbra spot.
New region S3710 [S20W27] emerged with a penumbra spot.
New region S3711 [S12W69] emerged with penumbra spots.
New region S3712 [S06E42] emerged with a penumbra spot.
New region S3713 [N18W09] emerged with penumbra spots.

C2+ Flares (GOES):

Magnitude Peak time (UTC) Location AR
       

Coronal mass ejections (CMEs)

August 4-6: 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 fair.

Forecast

The geomagnetic field is expected to be quiet on August 7-9. There is a chance of weak effects from CH630 on August 8-9.

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
12125 2014.07.25
2014.07.26
      S14W81           plage
12127 2014.07.27 6 6 2 S08W62 0060 DAO BXO

area: 0020

12128 2014.07.27 1 8 4 S20W61 0010 CAO CAO  
12130 2014.07.28
2014.07.29
9 28 5 S07W41 0030 HRX CRO images/AR_12130_20140806_2345.png images/AR_12130_20140805_2345.png  
12131 2014.07.28
2014.07.29
      S19W51         plage
12132 2014.07.30
2014.07.31
30 45 24 S20W21 0210 EAC EAC beta-gamma

area: 0400

location: S19W18

S3690 2014.07.30       N22W23           plage
S3693 2014.07.31       S16W08            
12133 2014.08.01
2014.08.02
      N18E04         plage
S3696 2014.08.01   5 2 S04W27 0010   AXX  
12134 2014.08.01
2014.08.02
9 34 19 N09E15 0140 DAI DAI beta-gamma

location: N10E18

S3700 2014.08.01       S07W38           plage
S3702 2014.08.03   3   N07W18 0006   BXO    
S3703 2014.08.04       N12E35         plage
S3704 2014.08.04       N05W11           plage
S3705 2014.08.04       S20W46           plage
S3706 2014.08.04       N20W53           plage
S3707 2014.08.05   4 2 S21E35 0010   CRO  
12135 2014.08.06 4 11 5 N11E64 0030 CRO DAO   area: 0170
S3709 2014.08.06   1 1 S15E02 0004   AXX    
S3710 2014.08.06   1   S20W27 0001   AXX    
S3711 2014.08.06   2 1 S12W69 0008   BXO    
S3712 2014.08.06   1 1 S06E42 0003   AXX    
S3713 2014.08.06   2   N18W09 0003   AXX    
Total spot count: 59 151 66  
Sunspot number: 119 291 176  (total spot count + 10 * number of spotted regions)
Weighted SN: 85 177 92  (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): 71 102 97 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
2014.08 148.5 (1)   26.4 (2A) / 136.3 (2B) / 72.8 (2C) (66.5 projected, -3.4) (7.5)

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.