Solar Terrestrial Activity Report

Activity chart

Last major update issued on October 29, 2015 at 05:50 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 (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 very quiet on October 28. Solar wind speed at SOHO ranged between 275 and 355 km/s. A proton flux enhancement was observed beginning at ACE at 02:30 UT on October 29. The source of this enhancement is uncertain.

Solar flux at 20h UTC on 2.8 GHz was 112.2 (decreasing 7.5 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 104.3. The Potsdam WDC planetary A index was 1 (STAR Ap - based on the mean of three hour interval ap indices: 1.0). Three hour interval K indices: 01000000 (planetary), 01000211 (Boulder).

The background x-ray flux is at the class B6 level.

At the time of counting spots (see image time), spots were observed in 9 active regions using 2K resolution (SN: 159) and 7 active regions using 1K resolution (SN: 98) SDO images on the visible solar disk.

Region 12436 [N08W78] decayed slowly and was mostly quiet.
Region 12437 [S19W62] developed slowly and produced a few low level C flares.
Region 12439 [N15W01] decayed slowly and quietly.
Region 12440 [N18W29] decayed slowly and quietly.
Region 12441 [N13E34] developed slowly and was quiet.
New region 12442 [N14E09] emerged on October 27 and was numbered the next day by SWPC.

Spotted regions not numbered (or interpreted differently) by SWPC:
New region S4854 [N07E80] rotated into view with large spots. M flares are possible.
New region S4856 [S05E76] rotated into view.
New region S4857 [N10E03] emerged with a tiny spot.

C2+ flares:

Magnitude Peak time (UTC) Location AR Recorded by Comment
           

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

Coronal mass ejections (CMEs)

October 26-28: 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 (CH697) will likely rotate into an Earth facing position on October 31-November 1.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle latitudes is good. If proton levels increase further propagation along poleward paths will suffer. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet on October 29-31.

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
12436 2015.10.16
2015.10.17
2 10 4 N08W74 0100 CAO EAO area: 0170

location: N08W78

12437 2015.10.18 7 11 3 S18W62 0020 CRO DRI area: 0040
12439 2015.10.22   3 1 N16W04 0006   AXX location: N15W01
S4843 2015.10.23       N19W27            
S4846 2015.10.25       S19W11            
12440 2015.10.25
2015.10.26
4 6 3 N19W31 0030 DSO DRO location: N18W29
S4849 2015.10.26       N13W20          
S4850 2015.10.26       S02W13          
12441 2015.10.27 2 17 7 N14E33 0020 DRO DRI area: 0080
12442 2015.10.27
2015.10.28
6 15 7 N16E09 0020 CAO DRI area: 0050

location: N14E09

S4853 2015.10.27       S18W16          
S4854 2015.10.28   5 3 N07E80 0450   CKO    
S4856 2015.10.28   1   S05E76 0002   AXX    
S4857 2015.10.28   1   N10E03 0001   AXX    
Total spot count: 21 69 28  
Sunspot number: 71 159 98  (total spot count + 10 * number of spotted regions)
Weighted SN: 42 96 55  (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): 78 87 83 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 (102.6)   51.1 (2A) / 56.6 (2B) / 70.6 (2C) (66.7 projected, -0.9) (14.7)

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.