Solar Terrestrial Activity Report

Activity chart

Last major update issued on October 17, 2015 at 06:15 UT. Updates may be incomplete until October 26.

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 (October 13, 2015)  

Recent activity

The geomagnetic field was quiet to unsettled on October 16. Solar wind speed at SOHO ranged between 346 and 440 km/s.

Solar flux at 20h UTC on 2.8 GHz was 109.1 (increasing 3.4 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 102.2. The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.0). Three hour interval K indices: 33111001 (planetary), 33312311 (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 7 active regions using 2K resolution (SN: 127) and 6 active regions using 1K resolution (SN: 88) SDO images on the visible solar disk.

Region 12431 [S18W02] decayed slowly and quietly.
Region 12432 [S20W25] decayed slowly and quietly.
Region 12434 [S10E34] gained spots and lost the magnetic delta. Although flare activity decreased with the loss of the delta, further M class flaring is possible.
New region 12435 [S15E73] rotated into view early in the day.

Spotted regions not numbered (or interpreted differently) by SWPC:
New region S4823 [N09E82] rotated partly into view and may be capable of M class flaring.
New region S4824 [N03E09] emerged with a tiny spot.
New region S4825 [N03W32] emerged with a tiny spot.

An active region at or just behind the southeast limb has produced several C flares early on October 17.

C2+ flares:

Magnitude Peak time (UTC) Location AR Recorded by Comment
M1.1 06:16 S11E46 12434 GOES15  
C3.4 09:03 S12E45 12434 GOES15  
C3.1 10:20   12434 GOES15  
C3.8 13:07   S4823 GOES15 incorrectly attributed to AR 12434 by SWPC
C4.3 13:24   12435 GOES15  
C4.2 13:42   12434 GOES15  

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

Coronal mass ejections (CMEs)

October 14-16: 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]

An extensive recurrent trans equatorial coronal hole (CH695) was in a geoeffective position on October 8-14. A northern hemisphere coronal hole (CH696) will likely rotate into an Earth facing position on October 17-18.

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 to fair.

Forecast

The geomagnetic field is expected to be quiet to unsettled on October 17-19. Quiet to active is possible on October 20-21 due to effects from CH696.

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
12429 2015.10.05
2015.10.06
      S19W80            
12430 2015.10.07
2015.10.08
      S17W48          
12432 2015.10.09
2015.10.11
4 10 4 S21W23 0010 BXO CRO location : S20W25
S4808 2015.10.09       S10W31            
12431 2015.10.10 1 7 2 S18W07 0030 HSX CAO

location: S18W02

S4811 2015.10.10       N15W23            
S4812 2015.10.10       S08W58            
S4815 2015.10.11       S00W57            
12434 2015.10.13 22 34 18 S10E34 0150 DAI DAC beta-gamma

area: 0270

S4819 2015.10.15       S12E18          
S4820 2015.10.15       S10W09          
12435 2015.10.16 1 2 1 S17E74 0020 HAX HAX   location: S15E73
S4823 2015.10.16   2 2 N09E82 0160   HAX    
S4824 2015.10.16   1 1 N03E09 0003   AXX    
S4825 2015.10.16   1   N03W32 0003   AXX    
Total spot count: 28 57 28  
Sunspot number: 68 127 88  (total spot count + 10 * number of spotted regions)
Weighted SN: 43 80 51  (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): 75 70 75 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) 15.78
2015.10 (92.8)   20.5 (2A) / 39.6 (2B) / 76.8 (2C) (66.7 projected, -0.9) (19.4)

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.