Solar Terrestrial Activity Report

Activity chart

Last major update issued on October 30, 2015 at 04:30 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 quiet on October 29. Solar wind speed at SOHO ranged between 276 and 342 km/s. A minor proton event began shortly after 02:30 UT due to a significant flare behind the southwest limb.

Solar flux at 20h UTC on 2.8 GHz was 112.9 (increasing 5.5 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 104.4. The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.0). Three hour interval K indices: 00111012 (planetary), 00212322 (Boulder).

The background x-ray flux is at the class B8 level.

At the time of counting spots (see image time), spots were observed in 9 active regions using 2K resolution (SN: 166) and 8 active regions using 1K resolution (SN: 122) SDO images on the visible solar disk.

Region 12436 [N11W83] rotated partly out of view and was quiet.
Region 12437 [S18W76] decayed losing almost all the spots that had emerged over the last few days.
Region 12439 [N18W12] decayed slowly and quietly.
Region 12440 [N18W43] was quiet and stable.
Region 12441 [N13E21] decayed slowly and quietly.
Region 12442 [N14W05] matured and was quiet.
New region 12443 [N07E68] rotated into view on October 28 and was numbered the next day by SWPC. The region was the source of nearly all the low level C flares recorded during the day. M class flares are possible.
New region 12444 [S05E61] rotated into view on October 28 and developed slowly on October 29 when it was numbered by SWPC.

Spotted regions not numbered (or interpreted differently) by SWPC:
New region S4860 [N19E78] rotated into view.

C2+ flares:

Magnitude Peak time (UTC) Location AR Recorded by Comment
           

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

Coronal mass ejections (CMEs)

October 27-29: 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 rotate into an Earth facing position on October 30-November 1.

Propagation

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

Forecast

The geomagnetic field is expected to be quiet on October 30-31. Late on November 1 a corotating interaction region associated with CH697 could cause unsettled to major storm conditions. These conditions will likely continue on November 2-3 due to effects from CH697.

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
3 6 4 N09W89 0060 CAO DRO  
12437 2015.10.18 1 2   S17W76 0030 CSO AXX area: 0005
12439 2015.10.22   2 1 N16W17 0006   AXX location: N18W12
S4843 2015.10.23       N19W40            
S4846 2015.10.25       S19W24            
12440 2015.10.25
2015.10.26
3 7 2 N20W44 0030 DAO DRO location: N18W43
S4849 2015.10.26       N13W33            
S4850 2015.10.26       S02W26            
12441 2015.10.27 7 13 8 N13E21 0030 CAI CRI  
12442 2015.10.27
2015.10.28
5 12 8 N15W03 0030 DRO DRO

location: N14W05

S4853 2015.10.27       S18W29            
12443 2015.10.28
2015.10.29
9 27 15 N05E67 0330 EHC EKC area: 0680

location: N07E68

12444 2015.10.28
2015.10.29
3 6 3 S04E61 0010 CRO CRO  
S4857 2015.10.28       N10W10          
S4860 2015.10.29   1 1 N19E78 0004   AXX    
Total spot count: 31 76 42  
Sunspot number: 101 166 122  (total spot count + 10 * number of spotted regions)
Weighted SN: 67 101 67  (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): 111 91 104 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 (103.0)   54.4 (2A) / 58.1 (2B) / 71.4 (2C) (66.7 projected, -0.9) (14.3)

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.