Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 4, 2015 at 06:15 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 on August 3, weakly under the decreasing influence of a high speed stream associated with CH679. Solar wind speed at SOHO ranged between 440 and 547 km/s.

Solar flux at 20h UTC on 2.8 GHz was 105.6 (decreasing 27.0 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 119.5. The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 4.9). Three hour interval K indices: 22211111 (planetary), 23322211 (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 14 active regions using 2K resolution (SN: 215) and 12 active regions using 1K resolution (SN: 161) SDO images on the visible solar disk.

Region 12391 [N08W15] decayed slowly and quietly.
Region 12392 [S05W14] reemerged with penumbra spots.
Region 12393 [N18W06] decayed slowly and quietly.
Region 12394 [N11E15] lost penumbral area in the largest spot, however, new flux emerged in the southern part and the region currently has polarity intermixing.
New region 12395 [N12E65] rotated into view on August 2 and was numbered by SWPC the next day.
New region 12396 [S18E57] emerged quickly with many spots. C flares are possible.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4647 [N17W24] decayed slowly and quietly losing most of the leading polarity spots.
S4648 [S22E04] reemerged with a penumbra spot.
S4656 [S06W03] reemerged with a penumbra spot.
S4659 [S12W50] decayed slowly and quietly.
New region S4663 [S10E36] was observed with a penumbra spot.
New region S4664 [S18E37] was observed with a penumbra spot.
New region S4665 [S13W08] emerged with a few spots.
New region S4666 [S06W22] emerged with a penumbra spot.

C2+ flares:

Magnitude Peak time (UTC) Location AR Recorded by Comment
           

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

Coronal mass ejections (CMEs)

August 1-3: 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.

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 on August 4-5. A high speed stream associated with CH680 could cause some unsettled and active intervals on August 6-7.

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
12389 2015.07.23
2015.07.24
      S12W77          
12391 2015.07.26
2015.07.27
1 12 6 N06W23 0001 AXX BXO location: N08W15

area: 0030

12392 2015.07.27
2015.07.29
  4 2 S05W22 0015   AXX   location: S05W14
12393 2015.07.27
2015.07.30
2 6 2 N18W06 0020 HAX CRO  
S4647 2015.07.27   10 7 N17W24 0030   BXO images/AR_S4647_20150803_2345.png images/AR_S4647_20150802_2345.png  
S4648 2015.07.28   1 1 S20E06 0003   AXX    
12394 2015.07.29
2015.07.30
4 18 9 N12E14 0120 CAO DAO beta-gamma

area: 0270

S4652 2015.07.29       S16W40            
S4653 2015.07.30       S25W18            
S4654 2015.07.30       S09W36            
S4655 2015.08.01       N33E18            
S4656 2015.08.01   1 1 S06W03 0004   AXX    
12395 2015.08.02
2015.08.03
1 2 2 N11E63 0030 HSX CAO area: 0050
S4659 2015.08.02   2   S12W50 0004   BXO  
S4660 2015.08.02       N06E02          
S4661 2015.08.02       N10W24          
12396 2015.08.03 4 13 7 S16E56 0010 HAX DAI   area: 0120

location: S18E57

S4663 2015.08.03   1 1 S10E36 0003   AXX    
S4664 2015.08.03   1   S18E37 0001   AXX    
S4665 2015.08.03   3 2 S13W08 0011   CRO    
S4666 2015.08.03   1 1 S06W22 0003   AXX    
Total spot count: 12 75 41  
Sunspot number: 62 215 161  (total spot count + 10 * number of spotted regions)
Weighted SN: 32 96 62  (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): 68 118 137 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 (103.3)   5.9 (2A) / 61.0 (2B) / 82.9 (2C) (69.0 projected, -1.2) (7.1)

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.