Solar Terrestrial Activity Report

Activity chart

Last major update issued on May 26, 2022 at 08:20 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 25. The high latitude magnetometer at Andenes recorded quiet to unsettled levels.

Solar flux density measured at 20h UT on 2.8 GHz was 136.5 - increasing 4.3 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 99.30). The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 5.1). Three hour interval K indices: 22220111 (planetary), 22222322 (Boulder), 23211333 (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 12 active regions using 2K resolution (SN: 202) and in 11 active regions using 1K resolution (SN: 146) SDO/HMI images.

Region 13014 [N22W74] decayed slowly and was mostly quiet. Only a small magnetic delta remains as the region is about to rotate over the northwest limb. A major flare is still possible. C1 flares: C1.2 02:20, C1.2 @ 04:26, C1.5 @ 05:20, C1.3 @ 07:41 UT
Region 13016 [S18W42] produced an M1.3 flare which also coincided with a filament eruption between this region and AR 13018. The region was mostly unchanged and has only tiny spots.
Region 13017 [N12W59] was mostly quiet and stable, however, activity increased early on May 26 and the region produced a C7.2 flare at 04:49 UT. The region has a small magnetic delta.
Region 13018 [S08W54] reemerged with a tiny spot.
Region 13019 [N12W08] decayed slowly and was mostly quiet. C1 flares: C1.5 @ 05:02 UT
Region 13020 [S21E19] decayed slowly and quietly.
Region 13021 [N13E29] decayed slowly and quietly.
Region 13022 [S08E43] decayed slowly and quietly.
New region 13023 [S14E65] rotated into view on May 24 and was numbered by SWPC the next day.
New region 13024 [S33E68] rotated into view on May 24 and received its NOAA number the following day.

Spotted regions not observed (or interpreted differently) by SWPC:
S7587 [N32W10] reemerged with a tiny spot.
New region S7594 [S20E08] emerged before noon with tiny spots, then decayed slowly.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.0 11:19 N11W03 13019 GOES16  
C2.1 16:40   13019 GOES16  
C2.6 16:48   13014 GOES16  
M1.3/1N 18:24 S19W41 13016 GOES16 CME, weak type IV and strong type II radio sweeps
C2.4 23:21 behind NW limb   GOES16  

Coronal mass ejections (CMEs)

May 23-25: No obviously Earth directed CMEs were observed in available LASCO imagery. Several CMEs were observed on May 25, mostly from backsided sources, the most impressive had its origin a few days behind the southeast limb. The CME associated with the eruption in AR 13016 appears not to have any significant Earth bound components.

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) rotated across the central meridian on May 24-26.

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 geomagnetic conditions are likely on most of May 26. A high speed stream from CH1080 could cause quiet to active conditions from late on May 26 until May 29.

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
13015 2022.05.13
2022.05.15
      N10W82            
13014 2022.05.13
2022.05.15
10 13 7 N22W74 0550 DKC DKC beta-delta
13016 2022.05.15
2022.05.16
  8 2 S18W47 0010   BXO location: S18W42
13017 2022.05.15
2022.05.16
4 14 6 N12W57 0110 DSO DAC

beta-delta

area: 0160

location: N12W59

13018 2022.05.16
2022.05.17
  1   S11W58 0001   AXX   location: S08W54
13019 2022.05.18
2022.05.19
  14 6 N14W09 0025   BXO  
S7579 2022.05.19       N16W37            
S7580 2022.05.20       S14W05          
13020 2022.05.20
2022.05.22
1 5 2 S21E18 0030 HSX CAO  
13021 2022.05.21
2022.05.22
4 14 7 N13E28 0010 BXO BXO area: 0025
S7585 2022.05.21       N13E09            
S7587 2022.05.22   1 1 N32W10 0003   AXX    
S7589 2022.05.23       S14W43            
S7590 2022.05.23       S14W33            
13022 2022.05.23
2022.05.24
1 6 1 S08E43 0000 AXX BXO area: 0010
13023 2022.05.24
2022.05.25
2 4 2 S13E65 0120 HSX HAX area: 0260
13024 2022.05.24
2022.05.25
1 1 1 S33E68 0050 HSX HSX area: 0080
S7594 2022.05.25   1 1 S20E08 0003   AXX  
Total spot count: 23 82 36  
Sunspot number: 93 202 146  (total spot count + 10 * number of spotted regions)
Weighted SN: 53 112 66  (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): 102 111 117  

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
2022.05 140.6 (1)   82.4 (2A) / 102.2 (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.