Solar Terrestrial Activity Report

Activity chart

Last major update issued on May 5, 2022 at 04:05 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 (May 1, 2022)
Solar cycle Solar cycles 23-25 (May 1, 2022) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (May 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 (May 1, 2022) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (May 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 on May 4. The high latitude magnetometer at Andenes recorded quiet to minor storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 130.1 - increasing 19.0 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 95.16). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 5.6). Three hour interval K indices: 12221012 (planetary), 22332212 (Boulder), 32223125 (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 9 active regions using 2K resolution (SN: 174) and in 8 active regions using 1K resolution (SN: 129) SDO/HMI images.

Region 12998 [S20W66] was quiet and stable. Note that SWPC 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 13001 [S31W27] was quiet and stable.
Region 13004 [S14W17] developed quickly and has a fairly strong magnetic delta within the leading penumbra. Major flares, including X class flares, are possible. C1 flares: C1.2 @ 03:19, C1.4 @ 03:47, C1.3 @ 04:32, C1.3 @ 06:47, C1.4 @ 22:09 UT
Region 13005 [N20W22] decayed slowly and quietly.
Region 13006 [S30E56] developed slowly and became less active. The main penumbra contains opposite polarity umbrae and this delta is likely the cause of most flares from this region. Another major flare is possible.

Spotted regions not observed (or interpreted differently) by SWPC:
S7542 [S15W18] was quiet and stable.
New region S7545 [S21W07] emerged with a tiny spot.
New region S7546 [S25E18]

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
M5.3 00:19 S30E80 13006 GOES16  
C2.4 02:32 S16E17 13004 GOES16  
C6.7 05:52 S30E78 13006 GOES16  
C3.5 08:25 S16W07 13004 GOES16  
M5.7/1B 08:59 S16W09 13004 GOES16 weak type IV radio sweep
C3.9 10:18 S15W09 13004 GOES16  
C2.7 12:04 S30E75 13006 GOES16 wrongly attributed to AR 13004 by SWPC
C2.4 12:55 S15W10 13004 GOES16  
C2.8 15:48 S16W13 13004 GOES16  
M1.1/1N 16:32 S16W11 13004 GOES16  
C6.5 17:05 S30E73 13006 GOES16  
C3.0 18:30 S16W13 13004 GOES16  
C8.6 19:05 S16W13 13004 GOES16  
M1.5 19:48 S28E74 13006 GOES16  
M1.6/1F 20:27 S16W13 13004 GOES16  
C3.0 22:59 S16W16 13004 GOES16  

Coronal mass ejections (CMEs)

May 2-4: 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 locations.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle and high latitudes is fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

Quiet conditions are likely on May 5-7.

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
12997 2022.04.22
2022.04.23
      N13W86          
12998 2022.04.23
2022.04.23
  1 1   0120   HSX

location: S20W66

12999 2022.04.25 1     S21W67 0090 HSX       SWPC renumber of AR 12998
S7518 2022.04.25       S08W52          
13000 2022.04.25
2022.04.26
      S17W38         location: S18W33
13001 2022.04.25
2022.04.26
1 4 3 S32W27 0090 HSX CSO location: S31W27

area: 0120

13002 2022.04.26
2022.04.28
      N13W58            
S7525 2022.04.26       N31W25            
S7526 2022.04.26       S17W44            
S7527 2022.04.26       N25W57            
13004 2022.04.27
2022.05.02
18 54 34 S16W17 0300 DKC DKC beta-gamma-delta

area: 0750

location: S14W17

13003 2022.04.28
2022.04.29
      S23W20          

location: S23W13

S7534 2022.04.30       N18W37          
13005 2022.05.01
2022.05.02
  5   N20W22 0007   AXX  
S7537 2022.05.02       S17E05            
S7538 2022.05.02       S19E15          
13006 2022.05.02
2022.05.04
4 7 4 S27E62 0050 CRO EAO  
S7540 2022.05.02       S13E56            
S7541 2022.05.04   7 4 S23W12 0015   BXO   wrongly numbered, this is AR 13003
S7542 2022.05.04   1 1 S17W03 0003   AXX    
S7543 2022.05.04   4 1 N32W09 0006   BXO    
S7544 2022.05.04   1 1 S30W39 0002   AXX    
Total spot count: 24 84 49  
Sunspot number: 64 174 129  (total spot count + 10 * number of spotted regions)
Weighted SN: 47 109 74  (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): 70 96 103  

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
 

2020.10

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 27.6 (+1.8) 5.52
2021.07 81.0 83.6 34.3 31.3 (+3.7) 5.51
2021.08 77.7 79.7 22.0 35.3 (+4.0) 6.19
2021.09 87.0 88.2 51.3 40.0 (+4.7) 6.33
2021.10 88.9 88.3 37.4 45.0 (+5.0) 7.38
2021.11 86.2 84.4 34.8 (50.0 projected, +5.0) 9.83
2021.12 103.0 99.8 67.5 (55.8 projected, +5.8) 6.40
2022.01 103.8 100.5 54.0 (60.3 projected, +4.5) 8.92
2022.02 109.1 106.5 59.7 (65.2 projected, +4.9) 10.46
2022.03 117.0 115.8 78.5 (70.7 projected, +5.5) 10.20
2022.04 130.8 131.7 84.1 (75.9 projected, +5.2) 12.0
2022.05 116.5 (1)   7.2 (2A) / 55.5 (2B) / 88.5 (2C) (82.3 projected, +6.4) (5.9)
2022.06       (88.2 projected, +5.9)  
2022.07       (95.4 projected, +7.2)  
2022.08       (102.1 projected, +6.7)  
2022.09       (107.1 projected, +5.0)  
2022.10       (110.3 projected, +3.2)  

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.