Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 13, 2023 at 10:30 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 12. Solar wind speed at SOHO ranged between 406 and 493 km/sec. The high latitude magnetometer at Andenes recorded quiet to unsettled levels.

Solar flux density measured at 20h UT on 2.8 GHz was 146.1 - increasing 11.8 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 143.65. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 5.5). Three hour interval K indices: 11112211 (planetary), 11123322 (Boulder), 21122223 (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: 257) and in 10 active regions using 1K resolution (SN: 153) SDO/HMI images.

Region 13326 [N25W54] was quiet and stable.
Region 13327 [S15W38] decayed losing spots and area. The region was mostly quiet. C1 flares: C1.5 @ 00:46, C1.9 @ 17:38 UT
Region 13329 [N23W38] was mostly quiet and stable. C1 flares: C1.6 @ 17:15 UT
Region 13330 [N17W58] decayed slowly and quietly.
Region 13331 [S22E01] was mostly quiet and stable. Polarity intermixing is observed in the central spot section and there is a slight chance of an M class flare. C1 flares: C1.3 @ 02:57, C1.4 @ 09:35 UT
Region 13332 [S08E05] decayed slowly and quietly.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S8629 [N14W22] was quiet and stable.
S8636 [N27W05] was quiet and stable.
S8639 [S12E36] decayed slowly and quietly.
S8644 [N30W52] reemerged with several spots.
S8645 [S24W23] was quiet and stable.
S8646 [S29E54] reemerged with tiny spots.
S8651 [S11E27] was quiet and stable.
New region S8653 [S12E66] emerged with tiny spots.

AR 13323 produced a few flares while transiting the southwest limb. C1 flares: C1.5 @ 00:38, C1.8 @ 03:15, C1.8 @ 14:33, C1.2 @ 18:27 UT
An active region behind the southeast limb produced a C1.8 flare at 01:42 UT

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C5.2/1N 06:58 N17W44 13330 GOES16 CME, moderate type II radio sweep
C2.6 08:55   13323 GOES16  
C3.6 10:04 behind northeast limb   GOES16  
C2.9 10:23   13323 GOES16  
C2.6 10:43 behind northeast limb   GOES16  
C2.7 13:19   13323 GOES16 incorrectly attributed to AR 13327 by SWPC
C2.2 15:08 behind northeast limb   GOES16  
C3.3 20:26 S24E04 13331 GOES16  
C2.2 21:44     GOES16  
C5.1 23:27     GOES16  

Coronal mass ejections (CMEs)

June 10-12: 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 recurrent trans equatorial coronal hole (CH1153) will rotate across the central meridian on June 12-13.

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 geomagnetic conditions are likely on June 13-14. Quiet to active conditions are expected for June 15-16 due to effects from CH1153.

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
13323 2023.05.30
2023.05.31
1     S07W90 0010 AXX    

spotless

rotated out of view

13326 2023.06.02
2023.06.02
1 2 1 N26W54 0060 HSX CSO location: N25W54

area: 0120

S8617 2023.06.02       N11W54          
13327 2023.06.03
2023.06.04
21 35 15 S15W40 0040 ESI ERI

location: S15W38

S8629 2023.06.04   13 4 N14W22 0020   BXO  
13330 2023.06.05
2023.06.06
2 2   N18W59 0000 AXX AXX

location: N17W58

area: 0003

13329 2023.06.05
2023.06.06
2 10 5 N23W39 0100 HSX CAO location: N23W38
13331 2023.06.06
2023.06.07
18 26 15 S23E03 0150 CSI EAI area: 0190
13332 2023.06.07
2023.06.07
1 1 1 S08E06 0000 AXX AXX location: S08E05

area: 0004

S8636 2023.06.07   3   N27W05 0003   BXO  
S8638 2023.06.09       N30W52            
S8639 2023.06.09   6 3 S12E36 0020   BXO  
S8640 2023.06.09       N12W02            
S8641 2023.06.09       S11W22            
S8642 2023.06.10       S16W03            
S8644 2023.06.10   5 3 N30W52 0020   CRO    
S8645 2023.06.10   2   S24W23 0005   BXO  
S8646 2023.06.10   2   S29E54 0002   AXX    
S8647 2023.06.10       S28W50            
S8648 2023.06.10       S42W38            
S8649 2023.06.10       S20E44            
S8651 2023.06.11   5 3 S11E27 0010   BXO  
S8652 2023.06.11       N18E54          
S8653 2023.06.12   5 3 S12E66 0010   BXO    
Total spot count: 46 117 53  
Sunspot number: 116 257 153  (total spot count + 10 * number of spotted regions)
Weighted SN: 66 138 74  (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): 128 141 122  

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
2023.06 163.4 (1)   54.1 (2A) / 135.2 (2B) / 160.7 (2C) (134.3 projected, +3.1) (5.3)
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.