Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 6, 2023 at 06:10 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 (June 1, 2023)
Solar cycle Solar cycles 23-25 (June 1, 2023) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (June 1, 2023) Noon SDO sunspot count 1K image / 4K (*)
  Solar cycles 1-24 (July 1, 2020) POES auroral activity level [October 2009 - December 2012]
  Comparison of cycles 21-25 (June 1, 2023) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (June 1, 2023) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (May 29, 2023) 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 June 5. Solar wind speed at SOHO ranged between 359 and 459 km/sec. The high latitude magnetometer at Andenes recorded quiet  levels.

Solar flux density measured at 20h UT on 2.8 GHz was 169.2 - decreasing 3.6 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 142.56. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.1). Three hour interval K indices: 11120022 (planetary), 11121322 (Boulder), 11120121 (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 18 active regions using 2K resolution (SN: 376) and in 13 active regions using 1K resolution (SN: 229) SDO/HMI images.

Region 13320 [N10W21] decayed slowly and quietly.
Region 13321 [S15W11] developed slightly and was quiet.
Region 13323 [S08E08] displayed signs of decay with penumbral fragmentation observed for some of the larger spots. The region produced a few C flares. C1 flares: C1.6 @ 23:33 and C1.7 @ 00:03 UT
Region 13324 [N13W49] decayed early in the day, then developed a few new spots.
Region 13325 [N09W46] decayed slowly and quietly.
Region 13326 [N25E38] was quiet and stable.
Region 13327 [S15E56] was mostly quiet and stable. The region has a small magnetic delta in a northern trailing penumbra and could produce M flares. C1 flares: C1.9 @ 22:57 UT
New region 13328 [N09W02] emerged on June 4 and decayed after it was numbered by SWPC the next day.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S8606 [N11W18] decayed slowly and was mostly quiet.
S8610 [N29W13] was quiet and stable.
S8613 [S10W26] was quiet and stable.
S8617 [N11E37] was quiet and stable.
S8623 [N15W01] was quiet and stable.
S8625 [S27E12] was quiet and stable.
S8626 [N16W45] decayed slowly and quietly.
S8629 [N10E71] was quiet and stable.
New region S8630 [N17E41] emerged with tiny spots to the south of AR 13326.
New region S8631 [N23E55] emerged with several spots to the east of AR 13326. C1 flares: C1.7 @ 15:02 UT

AR 13119 produced a C1.9 flare at 07:53 UT while at the southwest limb.
An unnumbered region at the northwest limb produced a C1.7 flare at 17:36 UT

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C3.3 01:54   13327 GOES16  
C3.3 02:26   13327 GOES16  
C4.0 02:54 S07E23 13323 GOES16  
C3.7 03:38   13327 GOES16  
C2.0 05:00   13327 GOES16  
C2.7 06:16   13323 GOES16  
C3.5 06:38 N10W02 S8606 GOES16  
C2.5 10:10   S8606 GOES16  
C2.1 10:58 behind southeast limb   GOES16  
C2.5 11:14 S08E19 13323 GOES16  
C2.0 12:34   13327 GOES16  
C2.1 12:51   S8631 GOES16  
C2.6 14:18 behind southwest limb 13319 GOES16  
C3.6 21:28 behind southwest limb 13319 GOES16  

Coronal mass ejections (CMEs)

June 3-5: No obviously Earth directed CMEs were observed.

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 northern hemisphere coronal hole (CH1152) will be Earth facing on June 6-8.

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 to unsettled conditions are likely on June 6-8.

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
13319 2023.05.27
2023.05.29
1     S22W91 0060 HSX EHO   rotated out of view
13320 2023.05.28
2023.05.29
3 3 2 N10W21 0040 CSO HAX area: 0050
13321 2023.05.29
2023.05.30
14 30 13 S15W11 0200 HSX DKO

area: 0310

S8606 2023.05.29   4 2 N11W18 0015   CRO  
S8609 2023.05.30       N18W36            
S8610 2023.05.30   2   N29W13 0003   AXX  
13324 2023.05.30
2023.06.02
  3 2 N11W52 0006   BXO location: N13W49
13323 2023.05.30
2023.05.31
35 69 40 S08W04 0330 EKI FAC

beta-gamma

area: 0580

location: S08E08

SWPC location is way off

S8613 2023.06.01       S08W22            
13325 2023.06.01
2023.06.02
2 3 1 N09W43 0040 HRX CRO location: N09W46

area: 0020

13326 2023.06.02
2023.06.02
3 5 2 N26E40 0190 HSX CSO location: N25E38

area: 0140

S8617 2023.06.02   3 1 N11E37 0010   CRO  
S8618 2023.06.03       N19W49          
13327 2023.06.03
2023.06.04
10 41 24 S15E56 0120 DAI DAC beta-delta

area: 0310

S8623 2023.06.03   3   N15W01 0006   AXX  
S8624 2023.06.03       S03W33            
S8625 2023.06.03   3   S27E12 0005   BXO  
S8626 2023.06.04   2   N16W45 0002   AXX  
13328 2023.06.04
2023.06.05
3 4 2 N11W03 0010 AXX BXO area: 0007

location: N09W02

S8629 2023.06.04   1 1 N10E71 0007   AXX  
S8630 2023.06.05   8 2 N17E41 0013   BXO    
S8631 2023.06.05   12 7 N23E55 0040   DRO    
Total spot count: 71 196 99  
Sunspot number: 151 376 229  (total spot count + 10 * number of spotted regions)
Weighted SN: 109 248 159  (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): 166 207 183  

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 (SC24 solar max) 7.88
2017.09 91.3 92.3 43.6 18.2 (-1.3) 18.22
(SC24 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
2021.10 88.9 88.3 37.4 45.2 (+5.0) 7.38
2021.11 86.2 84.4 34.8 50.8 (+5.6) 9.83
2021.12 103.0 99.8 67.5 55.9 (+5.1) 6.40
2022.01 103.8 100.5 55.3 60.1 (+4.2) 8.92
2022.02 109.1 106.5 60.9 64.7 (+4.6) 10.46
2022.03 117.0 115.8 78.6 68.7 (+4.0) 10.20
2022.04 130.8 131.7 84.0 73.0 (+4.3) 11.79
2022.05 133.8 136.8 96.5 77.4 (+4.4) 7.48
2022.06 116.1 119.8 70.3 81.1 (+3.7) 8.20
2022.07 125.4 129.5 91.4 86.7 (+5.6) 9.51
2022.08 114.2 117.1 74.6 92.5 (+5.8) 10.92
2022.09 135.1 136.5 96.0 96.4 (+3.9) 12.18
2022.10 133.5 132.7 95.5 98.7 (+2.3) 11.16
2022.11 123.4 120.7 80.5 101.0 (+2.3) 9.33
2022.12 147.9 143.4 112.8 (105.8 projected, +4.8) 10.99
2023.01 182.4 176.6 143.6 (112.2 projected, +6.4) 8.73
2023.02 167.2 163.2 110.9 (117.0 projected, +4.8) 14.48
(current
SC25 peak)
2023.03 157.2 155.6 122.6 (120.1 projected, +3.1) 14.42
2023.04 145.4 146.4 96.4 (125.5 projected, +5.4) 13.40
2023.05 155.6 159.2 137.9 (131.2 projected, +5.7) 10.9
2023.06 165.7 (1)   22.1 (2A) / 132.6 (2B) / 161.5 (2C) (134.3 projected, +3.1) (6.1)
2023.07       (133.8 projected, -0.5)  
2023.08       (134.8 projected, +1.0)  
2023.09       (138.2 projected, +3.4)  
2023.10       (140.1 projected, +1.9)  
2023.11       (142.7 projected max SC25)  
2023.12       (142.6 projected, 0.1)  

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: WDC-SILSO, Royal Observatory Of Belgium, Brussels

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.