Solar Terrestrial Activity Report

Activity chart

Last major update issued on October 15, 2015 at 03:05 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 active on October 14 under the influence of a high speed stream from CH695. Solar wind speed at SOHO ranged between 457 and 582 km/s.

Solar flux at 20h UTC on 2.8 GHz was 100.7 (decreasing 6.1 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 102.1. The Potsdam WDC planetary A index was 19 (STAR Ap - based on the mean of three hour interval ap indices: 19.3). Three hour interval K indices: 44443232 (planetary), 54443222 (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 6 active regions using 2K resolution (SN: 105) and 5 active regions using 1K resolution (SN: 69) SDO images on the visible solar disk.

Region 12430 [S17W16] decayed slowly and quietly.
Region 12431 [S18E23] gained a trailing polarity spot and was quiet.
Region 12432 [S22E05] was mostly quiet and stable.
Region 12433 [N19W81] decayed slowly and quietly.
Region 12434 [S09E61] produced a few low level C flares and has minor polarity intermixing. The region may be capable of producing an M class flare.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4809 [N07W78] was quiet and stable

C2+ flares:

Magnitude Peak time (UTC) Location AR Recorded by Comment
C2.3 13:39 S09E68 12434 SDO/EVE C1.8 @ GOES15 @ 13:38

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

Coronal mass ejections (CMEs)

October 12-14: 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.

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 to good.

Forecast

The geomagnetic field is expected to be quiet to active on October 15-17 due to effects from CH695, occasional minor storm intervals are possible.

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
      S19W52         location: S20W45
12430 2015.10.07
2015.10.08
  2   S17W20 0010   AXX location: S17W16
S4803 2015.10.07       N03W53            
12432 2015.10.09
2015.10.11
5 15 5 S21E03 0020 DRO DRO area: 0070
S4808 2015.10.09       S10W05            
S4809 2015.10.09   1 1 N07W78 0004   AXX  
12431 2015.10.10 1 6 3 S17E20 0030 HSX CSO

area: 0050

S4811 2015.10.10       N15E03            
S4812 2015.10.10       S08W32            
12433 2015.10.11
2015.10.12
2 3 2 N19W83 0010 AXX BXO  
S4815 2015.10.11       S00W31            
S4816 2015.10.12       S20W46            
12434 2015.10.13 8 18 8 S08E60 0050 CAI CAI location: S09E75

area: 0180

Total spot count: 16 45 19  
Sunspot number: 56 105 69  (total spot count + 10 * number of spotted regions)
Weighted SN: 29 58 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): 62 58 59 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 (90.6)   16.8 (2A) / 36.9 (2B) / 77.8 (2C) (66.7 projected, -0.9) (21.2)

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.