Solar Terrestrial Activity Report

Activity chart

Last major update issued on October 22, 2015 at 05:50 UT. Minor update added at 07:35 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 to active on October 21 under the influence of a high speed stream from CH696. Solar wind speed at SOHO ranged between 345 and 530 km/s.

Solar flux at 20h UTC on 2.8 GHz was 129.0 (increasing 23.2 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 103.7. The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 9.5). Three hour interval K indices: 22112232 (planetary), 22322222 (Boulder).

The background x-ray flux is at the class B5 level.

At the time of counting spots (see image time), spots were observed in 7 active regions using 2K resolution (SN: 180) and 6 active regions using 1K resolution (SN: 112) SDO images on the visible solar disk.

Region 12434 [S10W33] decayed slowly and was mostly quiet. The region was the source of a long duration C4.5 event peaking near 03:30 UT on October 22.
Region 12435 [S14E07] was quiet and stable.
Region 12436 [N08E18] decayed in the trailing spot section and ost the magnetic delta while the leader spots increased in penumbral area.
Region 12437 [S19E28] was quiet and stable.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4835 [N18E09] was quiet and stable.
S4837 [N05W31] was quiet and stable.
New region S4839 [S18W10] emerged with tiny spots.

Minor update added at 07:35 UT: The C4 LDE in AR 12434 today was associated with a partial halo CME. The CME could reach Earth on October 25 and cause unsettled to minor storm conditions.

C2+ flares:

Magnitude Peak time (UTC) Location AR Recorded by Comment
C6.3/1F 04:34   12436 GOES15  
C2.7 05:37 N06E24 12436 GOES15  
C2.6 12:00   12436 GOES15  
C2.1 14:01   12436 SDO/EVE C1.7 @ GOES15 @ 13:58
C7.7/1N 17:56 N08E24 12436 GOES15  
C2.2 18:54   12434 SDO/EVE  
C2.0 19:37   12436 SDO/EVE  

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

Coronal mass ejections (CMEs)

October 19-21: 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 northern hemisphere coronal hole (CH696) was in an Earth facing position on October 17-19.

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.

Forecast

The geomagnetic field is expected to be quiet on October 22-24.

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
12431 2015.10.10       S19W72          

 

12434 2015.10.13 6 19 9 S10W36 0180 CAO CAO beta-gamma

location: S10W33

 

S4819 2015.10.15       S12W47            
12435 2015.10.16 2 9 5 S15E03 0020 CRO CRO location: S14E07
12436 2015.10.16
2015.10.17
23 52 29 N08E16 0290 EKI EKC beta-gamma

area: 0480

location: N08E18

S4824 2015.10.16       N03W56            
S4826 2015.10.17       S12W09            
S4827 2015.10.17       N22W29            
S4828 2015.10.17       S18W41            
12437 2015.10.18 2 21 6 S20E32 0020 HSX CSO location: S19E28
S4831 2015.10.18       N09W32            
S4832 2015.10.18       N19W17         images/AR_S4832_20151020_2345.png  
S4833 2015.10.18       N18E11            
S4834 2015.10.18       N09W42            
S4835 2015.10.20   3   N18E24 0004   AXX  
S4836 2015.10.20       N27E22          
S4837 2015.10.20   2 1 N05W31 0002   AXX  
S4838 2015.10.20       S25W37          
S4839 2015.10.21   4 2 S18W10 0010   BXO    
Total spot count: 33 110 52  
Sunspot number: 73 180 112  (total spot count + 10 * number of spotted regions)
Weighted SN: 56 133 75  (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): 80 99 95 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 (99.8)   33.6 (2A) / 49.6 (2B) / 79.8 (2C) (66.7 projected, -0.9) (18.2)

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.