Solar Terrestrial Activity Report

Activity chart

Last major update issued on May 25, 2022 at 08:50 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 very quiet on May 24. The high latitude magnetometer at Andenes recorded quiet to unsettled levels.

Solar flux density measured at 20h UT on 2.8 GHz was 146.9 - increasing 5.4 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 99.15). The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.0). Three hour interval K indices: 11011001 (planetary), 11112322 (Boulder), 22122103 (Andenes).

The background x-ray flux is at the class B9 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 11 active regions using 2K resolution (SN: 220) and in 10 active regions using 1K resolution (SN: 150) SDO/HMI images.

Region 13014 [N22W60] decayed slowly and was mostly quiet. The region still has multiple magnetic deltas. A major flare is still possible. C1 flares: C1.5 @ 02:01 UT
Region 13016 [S17W34] decayed slowly and quietly.
Region 13017 [N11W45] was mostly quiet and stable. The region has a small magnetic delta.
Region 13019 [N14E06] decayed further and was quiet.
Region 13020 [S21E32] was quiet and stable.
Region 13021 [N13E41] was quiet and stable.
New region 13022 [S08E58] rotated into view on May 23 and was numbered the next day by SWPC.

Spotted regions not observed (or interpreted differently) by SWPC:
S7580 [S14E08] reemerged with tiny spots.
S7588 [S18W64] was quiet and stable.
New region S7592 [S14E78] rotated into view before noon with two mature spots inside a large penumbra.
New region S7593 [S33E80] rotated into view with a mature spot.

AR 13011 produced a C1.7 flare at 02:54 and C1.4 flare at 13:32 UT while approaching the west limb.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C3.1 06:10   13010 GOES16 incorrectly attributed to AR 13014 by SWPC
C3.1 08:25   13014 GOES16  
C4.2/1F 09:05 N20W76 13011 GOES16  
C4.5 09:22 N13W34 13017 GOES16  
C3.6 12:05   13010 GOES16  
C5.1 22:17 S11E80 S7592 GOES16 CME, weak type II radio sweep

Coronal mass ejections (CMEs)

May 22-24: 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]

A southern hemisphere coronal hole (CH1080) will rotate across the central meridian on May 24-25.

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 to fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

Quiet geomagnetic conditions are likely on May 24-26. A high speed stream from CH1080 could cause unsettled and active conditions on May 27-28.

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
13010 2022.05.11
2022.05.12
3     S17W86 0000 BXO     spotless
13011 2022.05.12
2022.05.13
3     N18W88 0010 CRO    

location: N19W84

spotless

13015 2022.05.13
2022.05.15
      N14W67            
13014 2022.05.13
2022.05.15
16 30 15 N22W62 0720 DKC EKC beta-gamma-delta

location: N22W60

13016 2022.05.15
2022.05.16
1 5 2 S18W33 0010 AXX CRO  
13017 2022.05.15
2022.05.16
9 19 10 N13W42 0120 ESO DAI

beta-delta

area: 0160

location: N11W45

13018 2022.05.16
2022.05.17
      S11W44            
13019 2022.05.18
2022.05.19
4 18 5 N14E05 0010 BXO BXO area: 0025
S7579 2022.05.19       N16W24            
S7580 2022.05.20   4   S14E08     BXO    
13020 2022.05.20
2022.05.22
1 4 1 S21E31 0030 HSX CAO  
13021 2022.05.21
2022.05.22
5 16 7 N13E40 0010 BXO DRO area: 0030
S7585 2022.05.21       N13E22            
S7587 2022.05.22       N30W05            
S7588 2022.05.23   5 3 S18W64 0015   BXO  
S7589 2022.05.23       S14W30          
S7590 2022.05.23       S14W20          
13022 2022.05.23
2022.05.24
5 6 4 S08E57 0010 BXO CRO  
S7592 2022.05.24   2 2 S08E58 0250   HKX    
S7593 2022.05.24   1 1 S33E80 0080   HSX    
Total spot count: 47 110 50  
Sunspot number: 137 220 150  (total spot count + 10 * number of spotted regions)
Weighted SN: 70 154 94  (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): 151 121 120  

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) 11.79
2022.05 140.7 (1)   79.4 (2A) / 102.6 (2B) / 115.3 (2C) (82.3 projected, +6.4) (6.3)
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.