Solar Terrestrial Activity Report

Activity chart

Last major update issued on April 29, 2022 at 10:15 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 (April 10, 2022) 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 28 under the influence of relatively weak CME effects. The high latitude magnetometer at Andenes recorded quiet to major storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 132.2 - decreasing 14.4 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 94.39). The Potsdam WDC planetary A index was 14 (STAR Ap - based on the mean of three hour interval ap indices: 14.4). Three hour interval K indices: 43422233 (planetary), 34323433 (Boulder), 64323355 (Andenes).

The background x-ray flux is at the class B7 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 14 active regions using 2K resolution (SN: 231) and in 10 active regions using 1K resolution (SN: 130) SDO/HMI images.

Region 12993 [N20W83] was quiet and stable as it rotated partly out of view.
Region 12994 [N13W80] decayed slowly and was mostly quiet. C1 flares: C1.1 @ 01:37, C1.2 @ 12:10, C1.3 @ 19:46, C1.2 @ 23:52 UT
Region 12995 [N14W51] was mostly quiet and stable. C1 flares: C1.7 @ 05:06, C1.0 @ 07:55, C1.1 @ 19:11, C1.0 @ 20:32 UT
Region 12997 [N12W06] decayed slowly and was quiet.
Region 12998 [S19E11] was quiet and stable. Note that SWPC has assigned a new number (12999) to the region due to the faulty initial location of AR 12998. For data consistency the original number is used in this report.
Region 13000 [S17E45] was quiet and stable.
Region 13001 [S31E49] was quiet and stable.
New region 13002 [N14E26] emerged on April 26 and was numbered by SWPC 2 days later as the region was slowly decaying.

Spotted regions not observed (or interpreted differently) by SWPC:
S7510 [N24W13] was quiet and stable.
S7518 [S09E29] was quiet and stable.
S7525 [N31E51] decayed slowly and quietly.
S7529 [S15E67] was quiet and stable.
New region S7532 [S23E65] emerged with tiny spots.
New region S7533 [S35W09] emerged with tiny spots.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C6.7 03:06   12996 GOES16 LDE, simultaneous flare in AR 12998
C2.1 11:39   12994 GOES16  
C3.7 18:12   12994 GOES16  

Coronal mass ejections (CMEs)

April 26, 28: No obviously Earth directed CMEs were observed in available LASCO imagery.
April 27: A partial halo CME was observed after the C7.7 long duration event in AR 12996. The CME could reach Earth on April 30 and cause unsettled to minor storm conditions.

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 recurrent southern hemisphere coronal hole (CH1076) was Earth facing on April 26-27.

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 to fair.

Forecast

Quiet to minor storm conditions are likely on April 29 due to CME effects and effects from CH1076. Unsettled to minor storm conditions are possible on April 30 and May 1 due to the April 27 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
12993 2022.04.16
2022.04.16
3 2 1 N20W85 0080 HAX HAX

 

12994 2022.04.16
2022.04.16
10 7 5 N14W79 0300 EKO EKO

area: 0620

location: N13W80

12995 2022.04.18
2022.04.19
11 12 3 N14W52 0130 CSO CHO

area: 0280

12996 2022.04.19
2022.04.20
      N25W39         location: N25W33
S7510 2022.04.21   3   N24W13 0004   BXO  
12997 2022.04.22
2022.04.23
4 22 6 N12W04 0020 CRO ERO

location: N12W06

area: 0070

S7512 2022.04.22       N38W54            
S7514 2022.04.22       S15W56            
S7515 2022.04.22       S19W39            
12998 2022.04.23
2022.04.23
  17 6 S19W57 0180   CSO SWPC location way off

location: S19E11

12999 2022.04.25 6     S20E12 0110 HSX       SWPC renumber of AR 12998
S7517 2022.04.24       S18W50            
S7518 2022.04.25   4   S09E29 0005   BXO  
13000 2022.04.25
2022.04.26
2 8 4 S17E44 0020 HRX CRO location: S17E45
13001 2022.04.25
2022.04.26
1 4 1 S32E48 0130 HSX CSO location: S31E49

area: 0170

S7521 2022.04.25       S28W05          
S7523 2022.04.26       S05W57            
13002 2022.04.26
2022.04.28
1 3 1 N13E25 0010 AXX BXO area: 0006
S7525 2022.04.26   2 1 N31E51 0005   AXX  
S7526 2022.04.26       S15E32            
S7527 2022.04.26       N25E21            
S7529 2022.04.27   3 2 S15E67 0012   BXO  
S7530 2022.04.27       S13W01          
S7531 2022.04.28       S12W46          
S7532 2022.04.28   2   S23E65 0002   BXO    
S7533 2022.04.28   2   S35W09 0004   BXO    
Total spot count: 38 91 30  
Sunspot number: 118 231 130  (total spot count + 10 * number of spotted regions)
Weighted SN: 74 132 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): 130 127 104  

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) 10.20
2022.04 131.5 (1)   71.4 (2A) / 76.5 (2B) / 96.3 (2C) (75.4 projected, +5.2) (11.8)
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.