Solar Terrestrial Activity Report

Activity chart

Last major update issued on October 8, 2015 at 04:05 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 (October 1, 2015)
Solar cycle Solar cycles 23-24 (October 1, 2015) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24 progress (October 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 (October 1, 2015) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12, 13, 14, 16 and 24 (October 1, 2015) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs solar cycles (September 16, 2015)  

Recent activity

The geomagnetic field was active to severe storm on October 7. Solar wind speed at SOHO ranged between 356 and 797 km/s. The corotating interaction region associated with CH694 that arrived late on October 6 was the main solar wind source until about 20h UT when the high speed stream from CH694 arrived at ACE.

Solar flux at 20h UTC on 2.8 GHz was 80.5 (decreasing 3.0 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 104.3. The Potsdam WDC planetary A index was 65 (STAR Ap - based on the mean of three hour interval ap indices: 65.3). Three hour interval K indices: 46655676 (planetary), 46655564 (Boulder).

The background x-ray flux is at the class B1 level.

At the time of counting spots (see image time), spots were observed in 5 active regions using 2K resolution (SN: 67) and 5 active regions using 1K resolution (SN: 60) SDO images on the visible solar disk.

Region 12427 [N17W86] was quiet and stable.
Region 12429 [S19E46] decayed slowly and quietly.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4795 [S11W04] was quiet and stable.
New region S4802 [S17E76] rotated into view.
New region S4803 [N03E38] emerged with small spots.

C2+ flares:

Magnitude Peak time (UTC) Location AR Recorded by Comment
           

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

Coronal mass ejections (CMEs)

October 5-7: 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 (CH694) was in an Earth facing position on October 4-6. A recurrent northern hemisphere coronal hole (CH695) will rotate into a potentially geoeffective position on October 8-12.

Propagation

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

Forecast

The geomagnetic field is expected to be unsettled to minor storm on October 8 and quiet to active on October 9 due to effects from CH694. Quiet to major storm conditions are possible on October 10-11 due to effects from CH695.

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
12427 2015.09.27 1 1 1 N16W86 0100 HSX HSX

area: 0180

S4791 2015.09.30       N09W50            
S4792 2015.09.30       N21W24            
S4795 2015.10.02   9 4 S11W04 0025   BXO  
S4796 2015.10.03       N03W49            
12429 2015.10.05
2015.10.06
3 4 3 S19E42 0010 BXO BXO location: S19E46

area: 0020

S4798 2015.10.05       N27W52            
S4799 2015.10.06       N35E37          
S4800 2015.10.06       N52E24          
S4801 2015.10.06       S16W16          
S4802 2015.10.07   1 1 S17E76 0040   HAX    
S4803 2015.10.07   2 1 N03E38 0008   BXO    
Total spot count: 4 17 10  
Sunspot number: 24 67 60  (total spot count + 10 * number of spotted regions)
Weighted SN: 9 27 20  (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): 26 37 51 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
2014.04 143.9 144.8 112.5 116.4 (+2.1) (solar max) 7.88
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 97.3 (-4.6) 8.96
2014.11 154.8 151.4 103.6 94.7 (-2.6) 9.33
2014.12 158.7 153.8 112.9 92.2 (-2.5) 11.24
2015.01 141.9 137.3 93.0 89.3 (-2.9) 9.46
2015.02 129.1 126.0 66.7 86.1 (-3.2) 9.92
2015.03 125.9 124.6 54.5 82.2 (-3.9) 16.14
2015.04 128.8 129.7 75.3 (78.7 projected, -3.5) 10.73
2015.05 120.0 122.6 88.8 (75.9 projected, -2.8) 8.29
2015.06 122.3 126.1 66.5 (72.2 projected, -3.7) 13.15
2015.07 107.0 110.8 66.4 (68.5 projected, -3.7) 8.83
2015.08 105.4 108.0 64.6 (67.3 projected, -1.2) 14.58
2015.09 101.7 102.7 78.1 (67.6 projected, +0.3) 15.7
2015.10 (93.8)   8.4 (2A) / 37.0 (2B) / 82.6 (2C) (66.7 projected, -0.9) (21.0)

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.