Solar Terrestrial Activity Report

Activity chart

Last major update issued on May 28, 2022 at 07:25 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 minor storm on May 27. A high speed stream associated with CH1080 reached DSCOVR near 10h UT. The high latitude magnetometer at Andenes recorded quiet to major storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 113.6 - decreasing 6.1 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 99.48). The Potsdam WDC planetary A index was 16 (STAR Ap - based on the mean of three hour interval ap indices: 16.1). Three hour interval K indices: 01125434 (planetary), 11334533 (Boulder), 00126555 (Andenes).

The background x-ray flux is at the class B5 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 10 active regions using 2K resolution (SN: 146) and in 8 active regions using 1K resolution (SN: 96) SDO/HMI images.

Region 13017 [N13W79] rotated partly out of view and was mostly quiet. C1 flares: C1.6 @ 12:00 UT
Region 13019 [N16W33] decayed slowly and quietly.
Region 13020 [S21W06] was quiet and stable.
Region 13021 [N12E03] developed slowly and was mostly quiet.
Region 13022 [S08E16] was quiet and stable.
Region 13023 [S14E39] was mostly quiet and stable. C1 flares: C1.3 @ 15:43 UT
Region 13024 [S33E43] was mostly quiet and stable. C1 flares: C1.0 @ 00:39, C1.4 @ 19:33 UT

Spotted regions not observed (or interpreted differently) by SWPC:
New region S7595 [N28W21] emerged with tiny spots.
New region S7596 [N16E16] was observed with a tiny spot in an old plage area.
New region S7597 [S37W11] emerged with a tiny spot.

AR 13014 behind the northwest limb produced a C1.1 flare at 01:26 and a C1.9 flare at 02:30 UT.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.3 11:27   13021 GOES16  

Coronal mass ejections (CMEs)

May 25-27: 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 poor. Propagation on long distance northeast-southwest paths is poor to fair.

Forecast

Quiet to minor storm conditions are likely on May 28-29 due to a high speed stream associated with CH1080 becoming quiet to unsettled on May 30-31.

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
13016 2022.05.15
2022.05.16
      S19W75           location: S18W68
13017 2022.05.15
2022.05.16
1 1 1 N12W85 0010 AXX AXX

location: N13W79

area: 0003

13018 2022.05.16
2022.05.17
      S11W86           location: S08W80
13019 2022.05.18
2022.05.19
1 7   N14W36 0000 AXX BXO area: 0010
S7580 2022.05.20       S14W34          
13020 2022.05.20
2022.05.22
1 8 4 S21W09 0020 HRX CRO location: S21W06
13021 2022.05.21
2022.05.22
3 14 5 N13E02 0010 BXO CRO area: 0040
S7585 2022.05.21       N13W17            
S7587 2022.05.22       N32W36            
13022 2022.05.23
2022.05.24
  2   S08E15 0003   BXO  
13023 2022.05.24
2022.05.25
2 6 3 S14E38 0120 HAX HAX area: 0250
13024 2022.05.24
2022.05.25
1 3 1 S33E43 0060 HSX CSO area: 0080
S7594 2022.05.25       S20W18            
S7595 2022.05.27   3 2 N28W21 0010   AXX    
S7596 2022.05.27   1 1 N16E16 0003   AXX    
S7597 2022.05.27   1 1 S37W14 0003   AXX    
Total spot count: 9 46 18  
Sunspot number: 69 146 98  (total spot count + 10 * number of spotted regions)
Weighted SN: 22 62 34  (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): 76 81 78  

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
2022.05 138.9 (1)   87.5 (2A) / 100.4 (2B) / 111.6 (2C) (82.3 projected, +6.4) (6.6)
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.