Solar Terrestrial Activity Report

Activity chart

Last major update issued on May 21, 2022 at 10:20 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 to unsettled on May 20 under the influence of a high speed stream associated with CH1079. The high latitude magnetometer at Andenes recorded quiet to major storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 165.5 - increasing 5.6 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 98.21). The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.4). Three hour interval K indices: 23222323 (planetary), 12232423 (Boulder), 43233536 (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 11 active regions using 2K resolution (SN: 305) and in 8 active regions using 1K resolution (SN: 183) SDO/HMI images.

Region 13010 [S16W31] decayed in the leading and trailing spot section. New flux emerged in the central spot section where some development was observed.
Region 13011 [N19W29] developed slowly as new flux emerged.
Region 13014 [N22W08] is a large and complex spot group with multiple magnetic deltas within the huge penumbral area. An X class flare is possible. C1 flares: C1.9 @ 09:30 UT
Region 13015 [N14W12] decayed slowly and quietly.
Region 13016 [S19E19] decayed slowly and quietly.
Region 13017 [N14E15] has many small spots spread over a large area. The region became better defined than it has been over the last days and was merged with AR S7577, however, there is still significant polarity intermixing.
Region 13018 [S10E13] decayed slowly and quietly.
Region 13019 [N12E59] gained some area and has only small spots.

Spotted regions not observed (or interpreted differently) by SWPC:
New region S7580 [S12E59] was observed with tiny spots in an old plage area. C1 flares: C1.8 @ 09:25 UT
New region S7581 [S21E83] rotated into view with a single, mature spot.
New region S7582 [S30W11] emerged with a tiny spot.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C3.9 00:12 N22E03 13014 GOES16  
M3.0/1B 07:45 N20E03 13014 GOES16  
C2.4 11:57 N19W20 13011 GOES16  
C2.7 12:17 N20E03 13014 GOES16  
C2.8 12:29     GOES16  
C2.1 12:57 S12W25 13010 GOES16  
C3.6 17:24 N23W02 13014 GOES16  
C2.5 18:53 N18E13 13017 GOES16  
C8.4/1N 22:12 N13E60 13019 GOES16  
C5.2 23:37 N20W29 13011 GOES16  

Coronal mass ejections (CMEs)

May 18-20: 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 trans equatorial coronal hole (CH1079) was Earth facing on May 15-18.

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 unsettled conditions are likely on May 21 due to effects from CH1079 becoming quiet on May 22-23.

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
13007 2022.05.07
2022.05.08
1     S22W89        

rotated out of view

13008 2022.05.10
2022.05.11
      N16W89            
13013 2022.05.11
2022.05.14
      S27W53         location: S26W49
13010 2022.05.11
2022.05.12
9 36 17 S14W31 0050 CRO DRI

location: S16W31

13011 2022.05.12
2022.05.13
  13 6 N16W34 0040   CRI

location: N19W29

13015 2022.05.13
2022.05.15
2 14 6 N14W13 0020 CSO CRO area: 0040
13014 2022.05.13
2022.05.15
12 59 33 N24W09 1190 DKC EKC beta-gamma-delta

location: N22W08

13016 2022.05.15
2022.05.16
5 12 7 S19E21 0070 DAO DAO location: S19E19
S7573 2022.05.15       N05W41           likely SC24 group
13017 2022.05.15
2022.05.16
6 39 21 N14E14 0030 CRO CRI

area: 0080

black area in image masks spots in AR S7577

13018 2022.05.16
2022.05.17
  2   S11E12 0002   BXO  
S7576 2022.05.16       N31W53            
S7577 2022.05.18       N16E08         merged with AR 13017 on 2022.05.20
13019 2022.05.18
2022.05.19
4 16 12 N11E55 0020 CRO BXO area: 0060

location: N13E59

S7579 2022.05.19       N21E35          
S7580 2022.05.20   2   S12E59 0002   BXO    
S7581 2022.05.20   1 1 S21E83 0060   HSX    
S7582 2022.05.20   1   S30W11 0002   AXX    
Total spot count: 39 195 103  
Sunspot number: 109 305 183  (total spot count + 10 * number of spotted regions)
Weighted SN: 73 230 138  (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): 120 168 146  

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
2022.05 137.1 (1)   62.7 (2A) / 97.3 (2B) / 111.0 (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.