Solar Terrestrial Activity Report

Activity chart

Last major update issued on May 2, 2022 at 08:10 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 to unsettled on May 1, weakly under the influence of a high speed stream from CH1076. The high latitude magnetometer at Andenes recorded quiet to minor storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 109 - decreasing 19.0 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 94.77). The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 7.5). Three hour interval K indices: 33211112 (planetary), 23322222 (Boulder), 45222332 (Andenes).

The background x-ray flux is at the class B6 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 9 active regions using 2K resolution (SN: 149) and in 7 active regions using 1K resolution (SN: 99) SDO/HMI images.

Region 12997 [N11W47] was quiet and stable.
Region 12998 [S20W27] 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 [S17E06] reemerged with tiny spots.
Region 13001 [S32E11] was quiet and stable.

Spotted regions not observed (or interpreted differently) by SWPC:
S7518 [S11W08] was quiet and stable.
S7521 [S28W42] reemerged with tiny spots.
S7529
[S16E28] was quiet and stable.
S7534 [N17E01] was quiet and stable.
New region S7535 [N22E17] emerged with a tiny spot.

AR 12994 produced a few flares from well behind the northwest limb. C1 flares: C1.8 @ 08:16, C1.1 @ 15:10, C1.7 @ 18:32 UT

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.2 00:25 behind NW limb 12994 GOES16  
C3.1 11:28 behind SE limb   GOES16 LDE
C2.6 13:26   12996 GOES16  
C2.5 22:18 behind NW limb 12994 GOES16  

Coronal mass ejections (CMEs)

April 30 - May 1: No obviously Earth directed CMEs were observed in available LASCO imagery.
April 29: A fast CME was observed off the northwest limb after the M1.2 flare in AR 12996 at 07:30 UT. Faint and slower components of the CME was observed around most of the visible disk and there is a chance of a weak impact on May 2.

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.

Forecast

Quiet to unsettled conditions are likely on May 2 due to lingering effects from CH1076 with a chance of unsettled to minor storm conditions should the April 29 CME reach Earth. Quiet to unsettled is likely on May 3-4.

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
12995 2022.04.18
2022.04.19
1     N15W93 0090 HSX    

rotated out of view

12996 2022.04.19
2022.04.20
      N25W81           location: N25W72
S7510 2022.04.21       N24W52            
12997 2022.04.22
2022.04.23
  7 3 N13W46 0015   BXO  
12998 2022.04.23
2022.04.23
  25 11   0170   CSO

location: S20W27

12999 2022.04.25 3     S20W27 0080 HAX       SWPC renumber of AR 12998
S7518 2022.04.25   5 2 S11W08 0010   BXO  
13000 2022.04.25
2022.04.26
  4 3 S17E04 0014   AXX   location: S17E06
13001 2022.04.25
2022.04.26
2 6 5 S32E09 0110 HAX CSO location: S32E11
S7521 2022.04.25   3   S28W42 0003   AXX    
13002 2022.04.26
2022.04.28
      N13W15            
S7525 2022.04.26       N31E14          
S7526 2022.04.26       S17W05          
S7527 2022.04.26       N25W18            
S7529 2022.04.27   3 3 S16E28 0007   AXX  
S7530 2022.04.27       S13W40            
13003 2022.04.28
2022.04.29
      S23E22        

location: S23E26

S7533 2022.04.28       S35W48            
S7534 2022.04.30   5 2 N17E01 0010   AXX  
S7535 2022.05.01   1   N22E17 0001   AXX    
Total spot count: 6 59 29  
Sunspot number: 36 149 99  (total spot count + 10 * number of spotted regions)
Weighted SN: 21 69 39  (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): 40 82 79  

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
2022.05 109 (1)   1.2 (2A) / 36 (2B) / 89.0 (2C) (82.3 projected, +6.4) (7.5)
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.