Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 16, 2023 at 08:20 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 (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 to minor storm on June 15 due to effects related to CH1153. Solar wind speed at SOHO ranged between 344 and 677 km/sec. The high latitude magnetometer at Andenes recorded quiet to major storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 153.1 - decreasing 11.5 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 143.72. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 23 (STAR Ap - based on the mean of three hour interval ap indices: 22.6). Three hour interval K indices: 11124545 (planetary), 12214545 (Boulder), 22124546 (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 15 active regions using 2K resolution (SN: 274) and in 11 active regions using 1K resolution (SN: 177) SDO/HMI images.

Region 13327 [S18W72] decayed slowly and was mostly quiet.
Region 13329 [N23W79] decayed quickly and was mostly quiet. C1 flares: C1.5 @ 10:40 UT
Region 13331 [S23W39] decayed slowly and quietly.
Region 13332 [S12W35] reemerged with tiny spots.
Region 13333 [S11E22] was mostly quiet and stable. The region could produce a minor M class flare.
Region 13334 [N15E49] was quiet and stable.
Region 13335 [S15E51] developed further and has M class flare potential. C1 flares: C1.4 @ 10:10 UT
Region 13336 [S21E57] decayed slowly and was the source of the largest flare of the day. C1 flares: C1.4 @ 06:26 UT
New region 13337 [N17E70] rotated into view on June 14 and was numbered the next day by SWPC.
New region 13338 [N11E71] rotated into view on June 14 and developed further as it was numbered by SWPC the following day. C1 flares: C1.3 @ 05:10 UT

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S8639 [S12W00] was quiet and stable.
New region S8665 [S12E08] emerged before noon with a tiny spot.
New region S8666 [N26W32] emerged with several spots.
New region S8667 [N27E09] emerged with a tiny spot.
New region S8668 [N17W17] emerged with a tiny spot.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.4 01:31 S15E66 13335 GOES16  
C6.0 03:17   13336 GOES16  
C2.4 07:09   13327 GOES16  
C2.0 07:53   13335 GOES16  
C2.6 08:22   13329 GOES16  
C2.7 09:10   13329 GOES16  
C9.7 12:55 S22E61 13336 GOES16 LDE
C4.2 14:15   13335 GOES16  
C2.0 17:07   13338 GOES16  
C2.8 17:17 N13E77 13338 GOES16  
C2.0 18:27   13338 GOES16  
C2.0 18:45   13329 GOES16  
C2.2 22:02   13327 GOES16  

Coronal mass ejections (CMEs)

June 13-15: 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) rotated across the central meridian on June 12-15. A southern hemisphere coronal hole (CH1154) will become Earth facing on June 16-17.

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 fair.

Forecast

Quiet to minor storm conditions are expected for June 16-17 due to effects from CH1153, quiet to unsettled is likely on June 18.

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
13327 2023.06.03
2023.06.04
  1   S17W79 0001   AXX

location: S17W63

13329 2023.06.05
2023.06.06
1 3 1 N24W78 0040 HSX HRX location: N23W79

area: 0020

13331 2023.06.06
2023.06.07
2 5 2 S23W40 0050 HAX CAO

area: 0090

13332 2023.06.07
2023.06.07
  2   S08W34 0002   AXX  

location: S12W35

S8636 2023.06.07       N27W50          
S8639 2023.06.09   5   S12W00 0008   BXO  
S8640 2023.06.09       N12W41            
S8642 2023.06.10       S16W42            
S8646 2023.06.10       S29E15            
S8649 2023.06.10       S20E05            
S8651 2023.06.11       S12W12            
S8652 2023.06.11       N18E15            
13333 2023.06.12
2023.06.13
7 31 17 S11E22 0130 DAI EAI area: 0240
13334 2023.06.13
2023.06.13
1 8 4 N17E47 0010 AXX BXO

location: N15E49

13336 2023.06.13
2023.06.14
9 17 12 S21E54 0130 DAO CAO

location: S21E57

S8657 2023.06.13       N20W30            
13335 2023.06.13
2023.06.14
9 29 17 S15E51 0150 ESO ESI area: 0390
S8660 2023.06.14       S20W22          
S8661 2023.06.14       N22E55          
13337 2023.06.14
2023.06.15
1 4 2 N17E69 0010 AXX CRO  
13338 2023.06.14
2023.06.15
2 7 4 N11E73 0020 CAO DAO area: 0130

location: N11E71

S8664 2023.06.14       S10W25          
S8665 2023.06.15   1 1 S12E08 0003   AXX    
S8666 2023.06.15   9 6 N26W32 0040   DRI    
S8667 2023.06.15   1 1 N27E09 0003   AXX    
S8668 2023.06.15   1   N17W17 0002   AXX    
Total spot count: 32 124 67  
Sunspot number: 112 274 177  (total spot count + 10 * number of spotted regions)
Weighted SN: 62 158 101  (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): 123 151 142  

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) 10.67
2023.06 160.3 (1)   64.6 (2A) / 129.3 (2B) / 160.4 (2C) (134.3 projected, +3.1) (6.3)
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.