Solar Terrestrial Activity Report

Activity chart

Last major update issued on April 5, 2022 at 07:55 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 4 under the influence of a high speed stream from CH1071. The high latitude magnetometer at Andenes recorded quiet to minor storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 128 - increasing 12.7 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 90.86). The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.1). Three hour interval K indices: 44222221 (planetary), 34332221 (Boulder), 54433251 (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 8 active regions using 2K resolution (SN: 170) and in 6 active regions using 1K resolution (SN: 108) SDO/HMI images.

Region 12978 [S16W27] was mostly quiet and stable.
Region 12981 [S24W22] decayed slowly and quietly.
Region 12982 [S22E13] was quiet and stable.
Region 12983 [N24E15] decayed slowly and quietly.
Region 12985 [S19E57] was quiet and stable.

Spotted regions not observed (or interpreted differently) by SWPC:
S7471 [N14W40] was quiet and stable.
New region S7479 [N14E04] emerged with a tiny spot.
New region S7480 [S31E81] rotated into view with a small spot.

AR 12984 behind the northwest limb was the source of a C1.5 flare at 03:29 UT.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.1 04:30   12976 GOES16  
C2.9 05:50   12976 GOES16  
C3.1 07:40   12976 GOES16  
C2.0 09:37   12976 GOES16  
C2.5 10:17   12984 GOES16  
C2.5 10:49   12979 GOES16  
C2.7 21:13   12982 GOES16 LDE, CME

Coronal mass ejections (CMEs)

April 2: A wide halo 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.
April 3: A large filament in the southwest quadrant erupted from 14:35 UT and may be associated with a faint halo CME that was observed in LASCO imagery starting just before 17h UT.
April 4: 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]

No obvious coronal holes are currently in or near Earth facing positions.

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 unsettled conditions are likely on April 5, however, should the April 2 CME arrive, we could see unsettled to minor storm conditions. On April 6-7 there is a chance of CME effects related to the April 3 CME and unsettled to minor storm conditions.

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
12976 2022.03.22
2022.03.24
1     N14W91 0280 HHX     rotated out of view
12978 2022.03.27
2022.03.27
12 43 26 S18W24 0370 EHI EHI

location: S16W27

12981 2022.03.27
2022.03.31
8 27 13 S26W21 0110 CRO DRI location: S24W22

area: 0070

S7461 2022.03.28       N20W53            
S7462 2022.03.28       S14W49          
S7463 2022.03.28       S42W42            
S7464 2022.03.28       S28W45            
12982 2022.03.29
2022.04.01
2 9 3 S20E10 0040 BXO BXO location: S22E13

area: 0020

S7469 2022.03.30       S18W08            
12983 2022.03.30
2022.04.02
1 2 2 N24E15 0030 HRX HAX  
S7471 2022.03.30   3   N14W40 0003   BXO  
S7472 2022.03.31       N14E06            
S7473 2022.03.31       S26W35            
12985 2022.04.02
2022.04.03
2 4 3 S20E55 0030 HAX CAO area: 0060

location: S19E57

S7477 2022.04.02       N23W37            
S7478 2022.04.03       S10W36          
S7479 2022.04.04   1   N14E04 0002   AXX    
S7480 2022.04.04   1 1 S31E81 0005   AXX    
Total spot count: 26 90 48  
Sunspot number: 86 170 108  (total spot count + 10 * number of spotted regions)
Weighted SN: 57 113 71  (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): 95 94 86  

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 40.0 (+4.7) 6.33
2021.10 88.9 88.3 38.1 (44.9 projected, +4.9) 7.38
2021.11 86.2 84.4 35.0 (50.5 projected, +5.6) 9.83
2021.12 103.0 99.8 67.6 (56.4 projected, +5.9) 6.40
2022.01 103.8 100.5 54.0 (60.0 projected, +3.6) 8.92
2022.02 109.1 106.5 59.7 (64.8 projected, +4.8) 10.46
2022.03 117.0 115.8 78.3 (70.2 projected, +5.4) 10.1
2022.04 139.5 (1)   14.7 (2A) / 110.5 (2B) / 95.2 (2C) (75.4 projected, +5.2) (13.0)
2022.05       (81.8 projected, +6.4)  
2022.06       (87.7 projected, +5.9)  
2022.07       (94.9 projected, +7.2)  
2022.08       (101.6 projected, +6.7)  
2022.09       (106.6 projected, +5.0)  

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.