Solar Terrestrial Activity Report

Activity chart

Last major update issued on December 3, 2021 at 07:40 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 (December 1, 2021)
Solar cycle Solar cycles 23-25 (December 1, 2021) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (December 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 (December 1, 2021) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (December 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 unsettled on December 2 under the influence of a high speed stream from CH1044. The high latitude magnetometer at Andenes recorded quiet to minor storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 86.6 - decreasing 6.2 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 80.35). The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.5). Three hour interval K indices: 22311322 (planetary), 11322322 (Boulder), 51322354 (Andenes).

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

At the time of counting spots (see image time), spots were observed in 9 active regions using 2K resolution (SN: 121) and in 7 active regions using 1K resolution (SN: 83) SDO/HMI images.

Region 12898 [S23W77] decayed slowly and quietly.
Region 12900 [S27W83] rotated partly out of view with only the decaying trailing spot section visible at the end of the day.
Region 12901 [N19E11] reemerged with tiny spots.
Region 12902 [N18W32] decayed slowly and quietly.
Region 12903 [S18E18] decayed slowly and quietly.

Spotted regions not observed (or interpreted differently) by SWPC:
New region S7216 [S17W69] emerged near noon with a tiny spot.
New region S7217 [S25W51] emerged with tiny spots.
New region S7218 [S29W65] emerged with tiny spots.
New region S7219 [S25E80] rotated into view with a small spot.

C2+ flares:

Magnitude Peak time (UT) Location AR Recorded by Comment
           

Coronal mass ejections (CMEs)

November 30 - December 2: 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 southern hemisphere coronal hole (CH1045) rotated across the central meridian on November 30-December 1. A trans equatorial coronal hole (CH1046) was Earth facing on December 1-2.

Propagation

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

Forecast

The geomagnetic field is expected to be quiet to minor storm on December 3-5 due to effects from CH1045 and CH1046.

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
12898 2021.11.22
2021.11.23
1 1 1 S25W78 0100 HSX HSX

location: S23W77

area: 0070

12900 2021.11.26
2021.11.26
1 1   S27W90 0000 AXX AXX location: S27W83

area: 0002

12901 2021.11.27
2021.11.28
  7 2 N16E10 0015   BXO   location: N19E11
S7209 2021.11.27       N19W50          
12902 2021.11.28
2021.11.30
13 12 6 N18W33 0100 DSI DRI area: 0050
S7211 2021.11.28       N22W55            
S7212 2021.11.29       S23W03            
12903 2021.11.29
2021.11.30
  2   S18E15 0002   AXX location: S18E18
S7215 2021.12.01       S25W17          
S7216 2021.12.02   1 1 S17W69 0003   AXX    
S7217 2021.12.02   2 1 S25W51 0004   BXO    
S7218 2021.12.02   4 1 S29W65 0007   BXO    
S7219 2021.12.02   1 1 S25E80 0030   HRX    
Total spot count: 15 31 13  
Sunspot number: 45 121 83  (total spot count + 10 * number of spotted regions)
Weighted SN: 25 42 24  (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): 50 67 66  

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 (SC24 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
2020.06 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 25.9 (+1.0) 6.50
2021.06 79.4 81.8 25.3 (26.9 projected, +1.0) 5.52
2021.07 81.0 83.6 34.4 (29.9 projected, +3.0) 5.51
2021.08 77.7 79.7 22.4 (34.6 projected, +4.7) 6.19
2021.09 87.0 88.2 51.5 (40.3 projected, +5.7) 6.33
2021.10 88.9 88.3 38.1 (44.7 projected, +4.4) 7.38
2021.11 86.2 84.4 35.1 (49.3 projected, +4.6) 9.9
2021.12 86.5 (1)   2.6 (2A) / 41.0 (2B) / 39.2 (2C) (55.1 projected, +5.8) (13.1)
2022.01       (58.7 projected, +3.6)  
2022.02       (63.5 projected, +4.8)  
2022.03       (68.9 projected, +5.4)  
2022.04       (74.0 projected, +5.1)  
2022.05       (80.4 projected, +6.4)  

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.