Solar Terrestrial Activity Report

Activity chart

Last major update issued on April 3, 2022 at 16:30 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 (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 minor storm on April 2 under the influence of CME effects (a solar wind shock was observed at 00:19 UT at DSCOVR, the arrival of the March 30 CME). The high latitude magnetometer at Andenes recorded quiet to major storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 143 - increasing 27.3 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 90.52). The Potsdam WDC planetary A index was 20 (STAR Ap - based on the mean of three hour interval ap indices: 20.0). Three hour interval K indices: 45422343 (planetary), 45523343 (Boulder), 66523465 (Andenes).

The background x-ray flux is at the class B8 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 11 active regions using 2K resolution (SN: 245) and in 9 active regions using 1K resolution (SN: 151) SDO/HMI images.

Region 12975 [N14W77] produced 2 M and several C flares as it rotated to the northwest limb.
Region 12976 [N14W63] was the source of a long duration M3.9 proton flare as the region decayed further.
Region 12978 [S17W01] was less active than on the previous and appears to be slowly decaying. C1 flares: C1.5 @ 22:52 UT
Region 12981 [S25E05] decayed slowly and produced a couple of C flares.
Region 12982 [S19E37] decayed slowly and quietly.
New region 12983 [N24E41] rotated into view on March 30 and was numbered by SWPC 3 days later.
New region 12984 [N12W68] emerged on April 1 with SWPC numbering the region the following day. Slow decay was observed after noon.

Spotted regions not observed (or interpreted differently) by SWPC:
S7469 [S17E10] decayed slowly and quietly.
S7471 [N12W16] decayed slowly and quietly.
New region S7475 [S20E81] rotated into view with a single mature spot.
New region S7477 [N23W11] was observed with tiny spots.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C3.2 01:06   12975 GOES16  
M2.9 02:56   12975 GOES16  
C2.0 04:24   12981 GOES16  
C3.9 05:05   12981 GOES16  
C2.1 06:29   12975 GOES16 attributed to AR 12984 by SWPC
C2.2 07:06   12975 GOES16  
C2.5 07:36   12984 GOES16  
C6.4 07:43 S26E17 12981 GOES16  
C6.5 08:25 N13W67 12975 GOES16 simultaneous flare in AR 12978
C3.4 08:39   12975 GOES16  
C2.6 10:46   12978 GOES16  
M3.9/1N 13:55 N15W61 12976 GOES16 LDE, partial halo CME, proton event, moderate type II radio sweep.
Flare covered a large area, including parts of AR 12984 and 12975.
M4.3/1N 17:44 N14W78 12975 GOES16  
C2.5 20:23   12975 GOES16  

Coronal mass ejections (CMEs)

April 1: No obviously Earth directed CMEs were observed in available LASCO imagery.
April 2: A wide CME was observed after the M3.9 proton long duration event in regions 12976/12975/12984 peaking at 13:55 UT. There is a chance that parts of this CME will reach Earth on April 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]

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 active conditions is likely on April 3 due to CME effects becoming quiet to unsettled on April 4. April 5 could see the arrival of the April 2 CME.

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
      S19W83          

location: S20W77

12975 2022.03.22
2022.03.23
9 11 4 N15W78 0260 EKC EAI

beta-gamma

location: N14W77

 

12976 2022.03.22
2022.03.24
4 7 5 N18W58 0420 EHO EKO

location: N14W63

12979 2022.03.25
2022.03.28
      S22W62         location: S17W51
12978 2022.03.27
2022.03.27
11 47 24 S18E03 0420 CHI EKI

location: S17W01

area: 0590

S7457 2022.03.27       N25W36            
12981 2022.03.27
2022.03.31
17 44 19 S25E06 0080 CRI DRI beta-gamma
S7459 2022.03.27       N40W44            
S7461 2022.03.28       N20W27            
S7462 2022.03.28       S14W24          
S7463 2022.03.28       S42W16            
S7464 2022.03.28       S28W19            
S7467 2022.03.29       S19W39            
12982 2022.03.29
2022.04.01
1 10 3 S19E34 0020 AXX CRO location: S19E37
S7469 2022.03.30   3   S18E18 0006   BXO  
12983 2022.03.30
2022.04.02
2 4 1 N20E42 0040 HSX CAO location: N24E41
S7471 2022.03.30   2 1 N12W16 0004   AXX  
S7472 2022.03.31       N14E32            
S7473 2022.03.31       S26W09            
12984 2022.04.01
2022.04.02
4 4 3 N12W69 0030 DRO DRO  
S7475 2022.04.02   1 1 S20E81 0070   HAX    
S7477 2022.04.02   2   N23W11 0004   BXO    
Total spot count: 48 135 61  
Sunspot number: 118 245 151  (total spot count + 10 * number of spotted regions)
Weighted SN: 89 179 105  (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): 130 135 121  

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
2022.03 117.0 115.8 78.3 (67.9 projected, +5.5) 10.1
2022.04 145 (1)   7.6 (2A) / 113.5 (2B) / 95.5 (2C) (73.0 projected, +5.1) (17.4)
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.