Solar Terrestrial Activity Report

Activity chart

Last major update issued on April 2, 2022 at 09:15 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 (March 1, 2022)
Solar cycle Solar cycles 23-25 (March 1, 2022) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (March 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 (March 1, 2022) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (March 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 active on April 1. The high latitude magnetometer at Andenes recorded quiet to minor storm levels. A solar wind shock was observed at 00:19 UT on April 2 at DSCOVR, the arrival of the March 30 CME.

Solar flux density measured at 20h UT on 2.8 GHz was 147 - increasing 26.9 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 90.33). The Potsdam WDC planetary A index was 15 (STAR Ap - based on the mean of three hour interval ap indices: 14.9). Three hour interval K indices: 33344222 (planetary), 23344312 (Boulder), 13243455 (Andenes).

The background x-ray flux is 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: 278) and in 10 active regions using 1K resolution (SN: 176) SDO/HMI images.

Region 12975 [N13W63] lost its magnetic delta and was much less active than during the previous days. M class flares are possible. C1 flares: C1.6 @ 22:16 UT.
Region 12976 [N14W49] decayed in the trailing spot section and was mostly quiet. An M class flare is possible.
Region 12978 [S17E13] developed as new flux emerged in the intermediate spot section. Flare activity increased. C1 flares: C1.9 @ 08:35, C1.8 @ 16:16, C1.6 @ 20:00 UT
Region 12979 [S17W38]reemerged with tiny spots.
Region 12981 [S25E20] produced numerous C flares and may be capable of producing an M class event. C1 flares: C1.9 @ 12:54, C1.9 @ 16:44, C1.9 @ 20:08 UT
New region 12982 [S19E48] rotated into view on March 29 and was numbered by SWPC 3 days later as the region decayed slowly.

Spotted regions not observed (or interpreted differently) by SWPC:
S7462 [S17W11] reemerged with several tiny spots.
S7466 [N20W79] reemerged with a tiny spot.
S7469 [S18E31] was quiet and stable.
S7470 [N23E54] was quiet and stable.
S7471 [N14W01] decayed slowly and quietly.
New region S7474 [N12W55] emerged between ARs 12976 and 12975 with a few spots.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C5.7 02:34   12981 GOES16  
C3.0 03:04   12981 GOES16  
C2.2 04:02   12981 GOES16  
C2.5 05:17   12981 GOES16  
C4.3 06:22   12978 GOES16  
C3.8 06:47   12978 GOES16  
C4.4 07:22   12981 GOES16  
C2.5 11:38   12975 GOES16  
C2.1 12:29   12978 GOES16  
C2.3 13:32   12978 GOES16  
C2.8 13:42   12978 GOES16  
C2.2 14:29   12978 GOES16  
C2.2 18:45   12975 GOES16  
C4.9 22:44   12981 GOES16  

Coronal mass ejections (CMEs)

March 31 + April 1: 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) 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
      S19W69          

location: S20W64

12975 2022.03.22
2022.03.23
24 28 13 N13W66 0300 EKC EAC

beta-gamma

location: N13W63

 

12976 2022.03.22
2022.03.24
6 20 8 N16W45 0410 EKO EKO

beta-gamma

location: N14W49

area: 0500

12979 2022.03.25
2022.03.28
  3 1 S22W48 0005   BXO   location: S17W38
12977 2022.03.26
2022.03.27
      N18W78           location: N21W77
12978 2022.03.27
2022.03.27
9 36 21 S18E14 0410 EKI FHI

location: S17E13

area: 0690

12980 2022.03.27
2022.03.28
      N04W82          

location: N08W79

S7457 2022.03.27       N25W23            
12981 2022.03.27
2022.03.31
19 51 25 S26E18 0080 DRI DRI beta-gamma

area: 0130

location: S25E20

S7459 2022.03.27       N40W31            
S7461 2022.03.28       N20W14            
S7462 2022.03.28   8   S14W11 0010   BXO    
S7463 2022.03.28       S42W03            
S7464 2022.03.28       S28W06            
S7466 2022.03.29   1   N20W79 0001   AXX    
S7467 2022.03.29       S19W26          
12982 2022.03.29
2022.04.01
1 5 2 S19E47 0020 HRX CRO  
S7469 2022.03.30   2 2 S18E31 0006   BXO  
S7470 2022.03.30   2 1 N23E54 0050   HSX  
S7471 2022.03.30   6 1 N14W01 0007   BXO  
S7472 2022.03.31       N14E45          
S7473 2022.03.31       S26E04          
S7474 2022.04.01   6 2 N12W55 0040   CRO    
Total spot count: 59 158 76  
Sunspot number: 109 278 176  (total spot count + 10 * number of spotted regions)
Weighted SN: 95 197 115  (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): 120 153 141  

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   78.3 (67.9 projected, +5.5) 10.1
2022.04 147 (1)   3.6 (2A) / 109 (2B) / 95.3 (2C) (73.0 projected, +5.1) (14.9)
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)  
2022.09          

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.