Solar Terrestrial Activity Report

Activity chart

Last major update issued on November 3, 2021 at 08:20 UT. Minor update added at 20:30 UT.

Charts (* = updated daily) Data and archive
  Solar wind (*) Solar and geomagnetic data - last month (*)
  Electron fluence (*) Archived daily reports and monthly data since 2003.01 (October 3, 2021)
Solar cycle Solar cycles 23-25 (October 1, 2021) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (October 1, 2021) Noon SDO sunspot count 1K image / 4K (*)
  Solar cycles 1-24 (June 1, 2020) POES auroral activity level October 2009 - December 2012]
  Comparison of cycles 21-25 (October 1, 2021) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (October 1, 2021) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (August 22, 2021) Cycle 25 spots (final update December 25, 2019)
  Solar cycles 24-25 transition using 365d smoothing Research: Solar Cycle 25 Started on November 17, 2019 with 365 Days Smoothing

Recent activity

The geomagnetic field was quiet to minor storm on November 2 under the influence of a high speed stream associated with CH1039. The high latitude magnetometer at Andenes recorded unsettled to major storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 97.0 - increasing 12.2 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 80.84). The Potsdam WDC planetary A index was 16 (STAR Ap - based on the mean of three hour interval ap indices: 16.1). Three hour interval K indices: 35343222 (planetary), 44343221 (Boulder), 65444355 (Andenes).

The background x-ray flux was at the class B1 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 6 active regions using 2K resolution (SN: 98) and in 4 active regions using 1K resolution (SN: 55) SDO/HMI images.

Region 12887 [S25W78] was quiet and stable.
Region 12891 [N16W10] still has a magnetic delta structure and could produce further M class flares.
Region 12893 [N15E46] was quiet and stable.

Spotted regions not observed (or interpreted differently) by SWPC:
New region S7168 [S10E13] emerged with tiny spots.
New region S7169 [S10W18] emerged with a tiny spot.
New region S7170 [N27W67] emerged with tiny spots.

Minor update posted at 20:30 UT: An impressive solar wind shock was arriving at DSCOVR at 19:25 UT, the arrival of the November 2 CME. The transit time was just over 40 hours. Solar wind speed is currently in excess of 700 km/sec. Expect minor to severe geomagnetic storming for the next 24-36 hours.

C2+ flares:

Magnitude Peak time (UT) Location AR Recorded by Comment
M1.7/1F 03:01 N14E01 12891 GOES16 full halo CME
C2.0 07:40 N19E01 12891 GOES16  

Coronal mass ejections (CMEs)

October 31: No obviously Earth directed CMEs were observed in available LASCO imagery.
November 1: Partial halo CMEs were observed after flares in AR S7142 peaking at 01:45 and 21:33 UT. The CMEs could reach Earth on November 4.
November 2: A fast full halo CME was observed after the M1.7 LDE in AR 12891 at 03:01 UT. The flare occurred while the region was crossing the central meridian and the CME is aimed almost directly at Earth. Active to severe storm conditions are possible on November 4-5.

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 extension (CH1039) of the northern pole coronal hole rotated across the central meridian on October 30-31.

Propagation

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

Forecast

The geomagnetic field is expected to be quiet to unsettled on November 3 and quiet to severe storm on November 4-5 due to CME effects.

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). 4K 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 officially numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC, all other regions are numbered sequentially as they emerge using the STAR spot number. 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. SWPC data considered to be not sufficiently precise (location, area, classification) are red colored.

Active region SWPC date numbered
STAR detected
Spot count Location at midnight Area Classification SDO / HMI 4K continuum
image with magnetic polarity overlays
Comment
SWPC/
USAF
Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
12887 2021.10.21
2021.10.22
1 1 1 S26W78 0120 HSX HSX

location: S25W78

area: 0100

S7142 2021.10.21       S30W70          
12888 2021.10.23
2021.10.24
      S12W57         location: S13W50
12889 2021.10.24
2021.10.25
      S24W49           location: S27W45
12891 2021.10.26
2021.10.26
10 28 11 N16W13 0120 DAI DAC beta-delta

area: 0180

S7159 2021.10.28       N24W16            
12892 2021.10.29
2021.10.30
      N26W57          
S7162 2021.10.29       S19W37            
12893 2021.10.30
2021.10.31
1 4 2 N16E44 0160 HSX CSO location: N15E46
S7165 2021.10.30       S22W26          
S7166 2021.10.31       N23W47            
S7167 2021.11.01       N28W22          
S7168 2021.11.02   2   S10E13 0002   BXO    
S7169 2021.11.02   1 1 S10W18 0003   AXX    
S7170 2021.11.02   2   N27W67 0003   AXX    
Total spot count: 12 38 15  
Sunspot number: 42 98 55  (total spot count + 10 * number of spotted regions)
Weighted SN: 27 53 30  (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): 46 54 44  

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number (4) Average ap
(3)
Measured 1 AU
2014.02 170.3
(cycle peak)
166.3 146.1 (cycle peak) 110.5 10.70
2014.04 143.9 144.8 112.5 116.4 (solar max) 7.88
2017.09 91.3 92.3 43.6 18.2 (-1.3) 18.22
(cycle peak)
2019.11 70.2 68.7 0.5 2.0 (-0.6)
(Solar minimum using 365d smoothing:
November 17, 2019)
4.19
2019.12 70.8 68.6 1.6 1.8 (-0.2)
(ISN 13 months smoothed
solar minimum)
3.22
2020.05 69.0 70.6 0.2 5.6 (+2.0) 3.80
2020.06 69.5 71.7 5.8 7.9 (+2.3) 3.75
2020.07 69.5 71.8 6.3 9.0 (+1.1) 4.28
2020.08 71.6 73.4 7.6 9.5 (+0.5) 5.68
2020.09 70.7 71.4 0.7 10.5 (+1.0) 8.59
2020.10 74.6 74.2 14.6 11.9 (+1.4) 6.13
2020.11 89.9 88.0 34.5 13.6 (+1.7) 4.77
2020.12 86.9 84.2 23.1 15.3 (+1.7) 4.72
2021.01 76.0 73.6 10.4 17.3 (+2.0) 4.39
2021.02 74.3 72.4 8.3 19.1 (+1.8) 9.50
2021.03 76.0 75.2 17.3 21.8 (+2.7) 10.17
2021.04 75.9 76.4 24.5 24.9 (+3.1) 8.40
2021.05 75.3 77.1 21.2 (26.6 projected, +1.7) 6.50
2021.06 79.4 81.8 25.3 (29.8 projected, +3.2) 5.52
2021.07 81.0 83.6 34.4 (34.4 projected, +4.6) 5.51
2021.08 77.7 79.7 22.4 (39.1 projected, +4.7) 6.19
2021.09 87.0 88.2 51.5 (44.8 projected, +5.7) 6.33
2021.10 88.9 88.3 38.1 (49.1 projected, +4.3) 7.3
2021.11 97.4 (1)   3.2 (2A) / 47.5 (2B) / 47.8 (2C) (53.7 projected, +4.6) (12.1)
2021.12       (59.6 projected, +5.9)  
2022.01       (63.2 projected, +3.6)  
2022.02       (67.9 projected, +4.7)  
2022.03       (73.4 projected, +5.5)  
2022.04       (78.5 projected, +5.1)  

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz and any corrections applied to that measurement.
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) Source: SIDC-SILSO.

Solar cycles 24-25

Smoothed SF and sunspot numbers

 

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.