Solar Terrestrial Activity Report

Activity chart

Last major update issued on May 22, 2022 at 08:00 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 21 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 166.7 - increasing 8.2 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 98.47). The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 9.8). Three hour interval K indices: 33212321 (planetary), 23324311 (Boulder), 56225522 (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 14 active regions using 2K resolution (SN: 353) and in 11 active regions using 1K resolution (SN: 218) SDO/HMI images.

Region 13010 [S16W44] decayed slowly producing a couple of C flares. C1 flares: C1.9 @ 19:06 UT
Region 13011 [N19W44] decayed slowly and quietly.
Region 13014 [N22W21] was mostly quiet despite being a large and complex spot group with multiple magnetic deltas. An X class flare is possible. C1 flares: C1.5 @ 04:35 UT
Region 13015 [N15W28] decayed slowly and quietly.
Region 13016 [S18E05] decayed slowly and quietly.
Region 13017 [N14W00] gained spots and area and could produce an M flare.
Region 13018 [S11W03] was quiet and stable.
Region 13019 [N12E47] developed slowly in the trailing spots section and was quiet.

Spotted regions not observed (or interpreted differently) by SWPC:
S7579 [N16E15] reemerged with tiny spots.
S7580
[S13E46] was quiet and stable.
S7581 [S21E70] was quiet and stable.
New region S7583 [N17W42] emerged with several spots just south of AR 13011.
New region S7584 [N13E82] rotated into view with small spots.
New region S7585 [N13E61] emerged with a tiny spot.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C3.5 00:13 N20W27 13011 GOES16  
C2.3 06:43   13014 GOES16  
C2.3 09:27   13014 GOES16  
C3.4 12:02   13014 GOES16  
C3.4 13:37 S16W39 13010 GOES16 simultaneous flare in AR 13014
C2.7 14:35 N16W27 13015 GOES16  
C2.5 15:39 N21W20 13010 GOES16 incorrectly attributed to AR 13014 by SWPC

Coronal mass ejections (CMEs)

May 19-21: 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. A southern hemisphere coronal hole (CH1080) will likely 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. Propagation on long distance northeast-southwest paths is poor to fair.

Forecast

Quiet to active conditions are likely on May 22 due to effects from CH1079 becoming quiet on May 23-24.

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
13013 2022.05.11
2022.05.14
      S27W67           location: S26W62
13010 2022.05.11
2022.05.12
9 28 11 S14W44 0020 CRO CRI

location: S16W44

area: 0040

13011 2022.05.12
2022.05.13
3 9 4 N15W47 0040   CRO

location: N19W44

13015 2022.05.13
2022.05.15
1 8 1 N14W25 0010 HSX HRX area: 0015
13014 2022.05.13
2022.05.15
14 58 32 N22W24 0940 EKC EKC beta-gamma-delta

location: N22W21

13016 2022.05.15
2022.05.16
2 20 10 S18E05 0040 CAO DAO  
S7573 2022.05.15       N05W54           likely SC24 group
13017 2022.05.15
2022.05.16
7 49 33 N14W00 0030 CRO ERI

area: 0140

black area in image masks spots in AR S7577

13018 2022.05.16
2022.05.17
  1   S11W02 0003   AXX  
13019 2022.05.18
2022.05.19
4 25 10 N11E41 0030 CRO CRI area: 0070

location: N12E47

S7579 2022.05.19   4 1 N16E15 0010   AXX    
S7580 2022.05.20   1   S13E45 0003   AXX  
S7581 2022.05.20   1 1 S21E70 0060   HSX  
S7582 2022.05.20       S30W24          
S7583 2022.05.21   6 4 N17W42 0020   CRO    
S7584 2022.05.21   2 1 N13E82 0020   CRO    
S7585 2022.05.21   1   N13E61 0001   AXX    
Total spot count: 40 213 108  
Sunspot number: 110 353 218  (total spot count + 10 * number of spotted regions)
Weighted SN: 74 254 149  (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): 121 194 174  

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
2022.05 138.5 (1)   66.3 (2A) / 97.9 (2B) / 112.9 (2C) (82.3 projected, +6.4) (6.5)
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.