Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 8, 2016 at 04:55 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 6, 2016)
Solar cycle Solar cycles 23-24 (August 1, 2016) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24 progress (August 1, 2016) Noon SDO sunspot count 1K / 4K (*)
  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, 2016) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12, 13, 14, 16 and 24 (August 1, 2016) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (July 9, 2016)  

Recent activity

The geomagnetic field was quiet to active on August 7 under the influence of a high speed stream from CH754. Solar wind speed at SOHO ranged between 462 and 572 km/s.

Solar flux at 20h UTC on 2.8 GHz was 92.7 (decreasing 2.0 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 88.8. The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 9.8). Three hour interval K indices: 42113312 (planetary), 42122322 (Boulder).

The background x-ray flux is at the class B7 level.

At the time of counting spots (see image time), spots were observed in 6 active regions using 2K resolution (SN: 116) and 5 active regions using 1K resolution (SN: 81) SDO images on the visible solar disk.

Region 12571 [N13W18] developed further and gained a small magnetic delta in the leading spot section. Minor M class flaring is possible.
Region 12572 [N13W71] decayed slowly and was mostly quiet.
New region 12573 [N03E74] rotated partly into view on August 6 and was numbered by SWPC the next day. Due to limb proximity it is not yet clear if the trailing spot is a separate region or not.
New region 12574 [N07E79] rotated into view.

Spotted regions not numbered (or interpreted differently) by SWPC:
New region S5394 [N10E32] was observed with tiny spots.
New region S5395 [N15E79] rotated into view.

C2+ flares:

Magnitude Peak time (UT) Location AR Recorded by Comment
C2.4 13:38     GOES15  
M1.3 14:44 SW limb S5389 GOES15  
C8.5 15:09 N09E82 12574 GOES15  
C2.0 21:49     GOES15  
C5.6 22:32   12571 GOES15  

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

Coronal mass ejections (CMEs)

August 4-6: No obviously Earth directed CMEs were observed in available LASCO 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 recurrent trans equatorial coronal hole (CH754) was Earth facing on August 2-4. The easternmost extension of CH753 was in an Earth facing position on August 6-7.

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 unsettled on August 8-10 as the easternmost part of CH753 becomes geoeffective.

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). 4K 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
12570 2016.07.28       N10W71            
12572 2016.08.02
2016.08.05
7 12 6 N13W72 0110 DAO CAI  
12571 2016.08.04 12 33 20 N12W19 0150 DAI DAC beta-gamma-delta

area: 0220

S5386 2016.08.04       S09W27            
S5390 2016.08.05       N20E21            
12573 2016.08.06
2016.08.07
2 2 2 N04E71 0060 DSO DSO could be two separate regions

area: 0090

12574 2016.08.07 2 3 2 N08E72 0060 DSO CAO   area: 0170

location: N07E79

S5394 2016.08.07   4   N10E32 0007   AXX    
S5395 2016.08.07   2 1 N15E79 0020   CRO    
Total spot count: 23 56 31  
Sunspot number: 63 116 81  (total spot count + 10 * number of spotted regions)
Weighted SN: 43 79 32  (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): 69 64 65 k * (sunspot number)
As of May 7, 2016: k = 1.1 for SWPC, k = 0.55 for MSN 2K, k = 0.80 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
2014.04 143.9 144.8 112.5 116.4 (+2.1) (solar max) 7.88
2015.05 120.0 122.6 88.8 76.1 (-2.8) 8.29
2015.06 122.3 126.1 66.5 72.1 (-4.0) 13.15
2015.07 107.0 110.8 65.8 68.3 (-3.8) 8.83
2015.08 105.4 108.0 64.4 66.4 (-1.9) 14.58
2015.09 101.7 102.7 78.6 65.9 (-0.5) 15.78
2015.10 104.1 103.3 63.6 64.3 (-1.6) 14.02
2015.11 109.3 106.9 62.2 61.3 (-3.0) 12.09
2015.12 113.1 109.5 58.0 57.8 (-3.5) 14.29
2016.01 103.4 100.1 57.0 54.5 (-3.3) 9.4
2016.02 103.6 101.0 56.4 (51.8 projected, -2.7) 9.9
2016.03 91.5 90.6 54.1 (48.2 projected, -3.6) 10.58
2016.04 93.3 94.0 38.0 (44.8 projected, -3.4) 9.03
2016.05 93.0 95.3 52.1 (42.1 projected, -2.7) 11.65
2016.06 81.9 84.5 20.9 (39.5 projected, -2.6) 8.44
2016.07 86.0 88.9 32.5 (36.8 projected, -2.7) 8.9
2016.08 (79.1)   5.9 (2A) / 26.1 (2B) / 40.2 (2C) (34.0 projected, -2.8) (13.6)

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).
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.