Solar Terrestrial Activity Report

Activity chart

Last major update issued on April 1, 2022 at 07:20 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 (April 1, 2022)
Solar cycle Solar cycles 23-25 (April 1, 2022) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (April 1, 2022) 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 (April 1, 2022) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (April 1, 2022) 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 March 31. The high latitude magnetometer at Andenes recorded quiet to minor storm levels. A solar wind shock was observed at 01:41 UT at DSCOVR, the arrival of one or both CMEs observed on March 28.

Solar flux density measured at 20h UT on 2.8 GHz was 149 - increasing 35.9 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 90.12). The Potsdam WDC planetary A index was 25 (STAR Ap - based on the mean of three hour interval ap indices: 25.0). Three hour interval K indices: 55444422 (planetary), 45344522 (Boulder), 55434342 (Andenes).

The background x-ray flux was at the class C1 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 12 active regions using 2K resolution (SN: 289) and in 11 active regions using 1K resolution (SN: 197) SDO/HMI images.

Region 12975 [N13W50] produced another major flare and numerous C flares. Further major flares are possible. C1 flares: C1.9 @ 02:54, C1.8 @ 03:40, C1.3 @ 23:12 UT.
Region 12976 [N15W34] decayed slowly and was mostly quiet. An M class flare is possible.
Region 12978 [S17E25] was mostly quiet and stable and has M class flare potential.
New region 12981 [S26E33] was finally numbered by SWPC, 4 days after rotating into view. The region developed slowly on March 31. C1 flares: C1.4 @ 00:25 UT

Spotted regions not observed (or interpreted differently) by SWPC:
S7465 [S04W64] decayed slowly and quietly. This is an SC24 group.
S7467 [S19W13] was quiet and stable.
S7468 [S18E60] was quiet and stable.
S7469 [S17E45] was quiet and stable.
S7470 [N23E68] was quiet and stable.
S7471 [N16E13] developed slowly and quietly.
New region S7472 [N14E58] emerged with a tiny spot.

AR S7455 behind the southwest limb produced several flares. C1 flares: C1.5 @ 07:22, C1.6 @ 17:18 UT.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C3.2 05:42   12975 GOES16  
C3.9 08:00 S24W90 S7455 GOES16  
C2.0 09:17 S24W90 S7455 GOES16  
C2.4 10:20 S24W90 S7455 GOES16  
C2.8 11:32 S24W90 S7455 GOES16  
C5.4 12:11 S24W90 S7455 GOES16  
C2.4 13:16   12981 GOES16 wrongly attributed to AR 12975 by SWPC
C2.9 14:13   12981 GOES16  
C3.8 14:38   12981 GOES16  
C2.1 15:14 S24W90 S7455 GOES16  
C2.0 16:00   12981 GOES16  
C2.0 16:47   12975 GOES16 simultaneous flare in AR S7455 behind the SW limb
C2.1 17:34 S24W90 S7455 GOES16  
M9.6/1B 18:35 N13W47 12975 GOES16 moderate type II radio sweep
C5.4 19:33   12981 GOES16  
C2.6 20:57 S15E23 12978 GOES16 CME?
C4.4 23:52   12975 GOES16  

Coronal mass ejections (CMEs)

March 30: A full halo CME was observed after the X1 event in AR 12975. The CME could impact Earth on April 1 or early on April 2 and cause active to major storm conditions. Another and more impressive full halo CME was observed early in the day in LASCO imagery. The source of this event was likely backsided, about 6 days behind the northeast limb given the distribution of the ejecta.
March 29, 31
: 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 (CH1071) will rotated across the central meridian on March 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 poor. Propagation on long distance northeast-southwest paths is poor.

Forecast

Quiet to major storm conditions is likely on April 1-3 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 colored red.

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
12974 2022.03.21
2022.03.22
      S19W55          

location: S20W51

12975 2022.03.22
2022.03.23
20 47 23 N13W52 0330 DKC EKC

beta-gamma-delta

area: 0420

12976 2022.03.22
2022.03.24
6 24 15 N16W31 0410 EKO EKO

beta-gamma

location: N15W34

area: 0550

12979 2022.03.25
2022.03.28
      S22W34         location: S19W27
12977 2022.03.26
2022.03.27
      N18W64           location: N21W64
12978 2022.03.27
2022.03.27
7 34 16 S18E28 0400 EHO EHO

location: S17E25

area: 0650

12980 2022.03.27
2022.03.28
      N04W68        

location: N08W66

S7457 2022.03.27       N25W10            
12981 2022.03.27
2022.03.31
11 44 22 S26E31 0030 DRI DRI beta-gamma

area: 0140

location: S26E33

S7459 2022.03.27       N40W18            
S7461 2022.03.28       N20W01            
S7462 2022.03.28       S14W04          
S7463 2022.03.28       S42E10            
S7464 2022.03.28       S28E07            
S7465 2022.03.29   2 1 S04W64 0010   HRX SC24 group
S7466 2022.03.29       N21W56            
S7467 2022.03.29   3 2 S19W13 0007   BXO  
S7468 2022.03.29   2 1 S18E60 0050   HAX  
S7469 2022.03.30   2 1 S17E45 0005   AXX  
S7470 2022.03.30   1 1 N23E68 0050   HSX  
S7471 2022.03.30   6 4 N16E13 0015   BXO  
S7472 2022.03.31   1   N14E58 0002   AXX    
S7473 2022.03.31   3 1 S26E17 0006   BXO    
Total spot count: 44 169 87  
Sunspot number: 84 289 197  (total spot count + 10 * number of spotted regions)
Weighted SN: 77 215 133  (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): 92 159 158  

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
2020.08 71.6 73.4 7.5 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 8.2 19.0 (+1.7) 9.50
2021.03 76.0 75.2 17.2 21.7 (+2.7) 10.17
2021.04 75.9 76.4 24.5 24.8 (+3.1) 8.40
2021.05 75.3 77.1 21.2 25.8 (+1.0) 6.50
2021.06 79.4 81.8 25.0 27.7 (+1.9) 5.52
2021.07 81.0 83.6 34.3 31.4 (+3.7) 5.51
2021.08 77.7 79.7 22.0 35.3 (+3.9) 6.19
2021.09 87.0 88.2 51.3 (39.9 projected, +4.6) 6.33
2021.10 88.9 88.3 38.1 (43.6 projected, +3.7) 7.38
2021.11 86.2 84.4 35.0 (48.2 projected, +4.6) 9.83
2021.12 103.0 99.8 67.6 (54.0 projected, +5.8) 6.40
2022.01 103.8 100.5 54.0 (57.7 projected, +3.7) 8.92
2022.02 109.1 106.5 59.7 (62.4 projected, +4.7) 10.46
2022.03 117.0 (1)   69.1 (2A/2B) / 94.3 (2C) (67.9 projected, +5.5) (10.1)
2022.04       (73.0 projected, +5.1)  
2022.05       (79.4 projected, +6.4)  
2022.06       (85.3 projected, +5.9)  
2022.07       (92.6 projected, +7.3)  
2022.08       (99.2 projected, +6.6)  

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.