Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 7, 2015 at 04:25 UT.

Charts (* = updated daily) Data and archive
  Solar wind (*) Solar and geomagnetic data - last month (*)
  Electron fluence (*) Archived daily reports and monthly data from 2003.01 (August 1, 2015)
Solar cycle Solar cycles 23-24 (August 1, 2015) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24 progress (August 1, 2015) Noon SDO sunspot count 1K Reference: 4K (large file) (*)
  Solar cycles 1-24 (July 17, 2015) POES auroral activity level October 2009 - December 2012
  Comparison of cycles 21, 22, 23 and 24 (August 1, 2015) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12, 13, 14, 16 and 24 (August 1, 2015) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs solar cycles (July 18, 2015)  

Recent activity

The geomagnetic field was quiet to unsettled on August 6, after 06h UT under the influence of effects from a high speed stream associated with CH680 (no co-rotating interaction region signature was observed). Solar wind speed at SOHO ranged between 349 and 602 km/s.

Solar flux at 17h UTC on 2.8 GHz was 116.9 (decreasing 12.1 over the last solar rotation, the measurement at 20h UT was enhanced by a C1.6 flare peaking at 19:58 UT with an origin in the northern part of AR 12396). The 90 day 10.7 flux at 1 AU was 118.4. The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.0). Three hour interval K indices: 21233223 (planetary), 31353223 (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 13 active regions using 2K resolution (SN: 228) and 9 active regions using 1K resolution (SN: 130) SDO images on the visible solar disk.

Region 12393 [N18W45] decayed slowly and quietly.
Region 12394 [N12W22] was quiet and stable.
Region 12395 [N12E27] decayed quietly.
Region 12396 [S18E16] developed gaining spots and penumbral area. There's weak polarity intermixing in the central section. An M class flare is possible.
Region 12397 [S12W55] decayed losing the trailing spots.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4648 [S23W35] was quiet and stable.
S4667 [S18E41] reemerged with penubra spots.
New region S4669 [N15E75] rotated into view.
New region S4670 [N22E34] emerged with a penumbra spot.
New region S4671 [N08W26] was split off from AR 12394.
New region S4672 [S15W31] emerged with penumbra spots.
New region S4673 [N05E03] emerged with a penumbra spot.
New region S4674 [N19W64] emerged with penumbra spots.

C2+ flares:

Magnitude Peak time (UTC) Location AR Recorded by Comment
C2.1 19:21 S17E34 12396 GOES15  

Flare activity (SDO/EVE/ESP XRS-B proxy)

Coronal mass ejections (CMEs)

August 4-6: No obviously Earth directed CMEs were observed.

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 recurrent trans equatorial coronal hole (CH680) was in an Earth facing position on August 3. A small coronal hole (CH681) near the equator was in an Earth facing location on August 6 and may be capable of causing a weak disturbance 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 poor to fair.

Forecast

The geomagnetic field is expected to be quiet to unsettled on August 7-8 due to a high speed stream associated with CH680 and quiet on August 9-10. Effects from a small coronal hole (CH681) could reach Earth on August 9 and cause a few unsettled intervals.

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 overlays
Comment
SWPC Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
12391 2015.07.26
2015.07.27
      N07W62          
12392 2015.07.27
2015.07.29
      S05W67           location: S05W54
12393 2015.07.27
2015.07.30
1 3 1 N18W46 0020 HAX CRO  
S4648 2015.07.28   2   S23W35 0003   AXX  
12394 2015.07.29
2015.07.30
6 19 7 N11W25 0100 CAO DAO

area: 0190

S4653 2015.07.30       S25W57            
S4655 2015.08.01       N33W21            
S4656 2015.08.01       S06W42            
12395 2015.08.02
2015.08.03
1 4 2 N12E25 0020 HAX CRO  
S4660 2015.08.02       N06W37            
12396 2015.08.03 20 52 22 S17E15 0550 EKC EKC area: 1020
S4663 2015.08.03       S10W03            
S4664 2015.08.03       S18W02            
12397 2015.08.03
2015.08.05
1 2 1 S12W54 0010 HAX HRX  
S4667 2015.08.04   2   S18E41 0003   AXX    
S4668 2015.08.05       S27W21          
S4669 2015.08.06   1 1 N15E75 0030   HRX    
S4670 2015.08.06   1 1 N22E34 0003   AXX    
S4671 2015.08.06   7 4 N08W26 0018   CRO    
S4672 2015.08.06   2   S15W31 0003   BXO    
S4673 2015.08.06   1 1 N05E03 0003   AXX    
S4674 2015.08.06   2   N19W64 0002   BXO    
Total spot count: 29 98 40  
Sunspot number: 79 228 130  (total spot count + 10 * number of spotted regions)
Weighted SN: 59 128 70  (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): 87 125 111 k * (sunspot number)
As of July 1, 2015: k = 1.1 for SWPC, k = 0.55 for MSN 2K, k = 0.85 for MSN 1K (MSN=Magnetic Sunspot Number)

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO) (4)
Smoothed sunspot number (4) Average ap
(3)
Measured 1 AU
2014.02 170.3
(cycle peak)
166.3 146.1 (cycle peak) 110.5 (+1.2) 10.70
2014.03 149.9 148.5 128.7 114.3 (+3.8) 4.88
2014.04 143.9 144.8 112.5 116.4 (+2.1) (solar max) 7.88
2014.05 129.7 132.9 112.5 115.0 (-1.4) 5.75
2014.06 122.0 125.8 102.9 114.1 (-0.9) 6.72
2014.07 137.4 141.8 100.2 112.6 (-1.5) 4.50
2014.08 124.7 127.9 106.9 108.3 (-4.3) 7.71
2014.09 146.6 148.1 130.0 101.9 (-6.4) 9.78
2014.10 153.4 152.9 90.0 97.4 (-4.5) 8.96
2014.11 154.8 151.4 103.6 95.0 (-2.4) 9.33
2014.12 158.7 153.8 112.9 92.6 (-2.4) 11.24
2015.01 141.9 137.3 93.0 89.8 (-2.8) 9.46
2015.02 129.1 126.0 66.7 (86.8 projected, -3.0) 9.92
2015.03 125.9 124.6 54.5 (83.1 projected, -3.7) 16.14
2015.04 128.8 129.7 78.0 (79.8 projected, -3.3) 10.73
2015.05 120.0 122.6 90.0 (77.4 projected, -2.4) 8.29
2015.06 122.3 126.1 68.3 (73.9 projected, -3.5) 13.15
2015.07 107.0 110.8 66.4 (70.2 projected, -3.7) 8.8
2015.08 (107.7)   13.5 (2A) / 69.5 (2B) / 77.3 (2C) (69.0 projected, -1.2) (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).
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.
4) Updated to new data set from WDC-SILSO on July 1, 2015

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 Universal Time. Comments and suggestions are always welcome.

SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.