Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 31, 2015 at 04:50 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 (August 18, 2015)  

Recent activity

The geomagnetic field was very quiet on August 30. Solar wind speed at SOHO ranged between 362 and 441 km/s.

Solar flux at 20h UTC on 2.8 GHz was 91.6 (decreasing 14.0 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 115.1. The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.5). Three hour interval K indices: 11110111 (planetary), 21212212 (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 8 active regions using 2K resolution (SN: 116) and 6 active regions using 1K resolution (SN: 78) SDO images on the visible solar disk.

Region 12405 [S22E11] was quiet and stable.
Region 12406 [N03E23] developed slowly and quietly.
New region 12407 [N16W48] emerged early in the day with several spots.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4703 [N22W18] was quiet and stable.
S4719 [S11W63] decayed slowly and quietly.
New region S4725 [S18E48] was observed with a penumbra spot.
New region S4726 [N10E13] emerged with a penumbra spot.
New region S4727 [N47W29] emerged at a high latitude with a tiny penumbra spot.

C2+ flares:

Magnitude Peak time (UTC) Location AR Recorded by Comment
C2.6 02:12   12403 SDO/EVE  
M1.4 (LDE) 03:30   12403 GOES15  

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

Coronal mass ejections (CMEs)

August 28-30: 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 (CH686) rotated across the central meridian on August 29-30.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle latitudes is poor to fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet on August 31 - September 1. A disturbance associated with CH686 could cause quiet to active conditions on September 2-3.

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
12403 2015.08.17
2015.08.18
2     S15W89 0080 DAO    

rotated out of view

S4703 2015.08.22   4 1 N22W18 0010   AXX  
12405 2015.08.26
2015.08.27
3 6 3 S20E09 0010 BXO BXO

location: S22E11

S4714 2015.08.27       S03W21            
S4715 2015.08.27       N11W10          
12406 2015.08.28
2015.08.29
2 7 5 N03E23 0010 AXX CRO  
S4719 2015.08.28   4 1 S11W63 0010   BXO  
S4720 2015.08.28       S18E12          
S4721 2015.08.28       S17W06          
S4723 2015.08.29       N03W40          
12407 2015.08.30 3 12 7 N15W48 0030 CRO DRI    
S4725 2015.08.30   1 1 S18E48 0003   AXX    
S4726 2015.08.30   1   N10E13 0003   AXX    
S4727 2015.08.30   1   N47W29 0001   AXX    
Total spot count: 10 36 18  
Sunspot number: 50 116 78  (total spot count + 10 * number of spotted regions)
Weighted SN: 18 42 24  (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): 55 64 66 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) 8.83
2015.08 (105.8)   59.8 (2A) / 61.8 (2B) / 75.0 (2C) (69.0 projected, -1.2) (14.2)

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.