Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 7, 2023 at 06:55 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 unsettled on June 6. Solar wind speed at SOHO ranged between 342 and 418 km/sec. The high latitude magnetometer at Andenes recorded quiet to minor storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 171.8 - increasing 1.7 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 142.77. 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: 32122111 (planetary), 33132321 (Boulder), 55123111 (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 16 active regions using 2K resolution (SN: 377) and in 13 active regions using 1K resolution (SN: 242) SDO/HMI images.

Region 13320 [N10W34] was quiet and stable.
Region 13321 [S15W23] was quiet and stable.
Region 13323 [S08W03] decayed significantly and was mostly quiet. C1 flares: C1.5 @ 00:24 UT
Region 13324 [N14W64] developed slowly and quietly.
Region 13325 [N09W59] decayed slowly and quietly.
Region 13326 [N25E25] was quiet and stable.
Region 13327 [S15E42] produced a number of C flares and has M class flare potential. The region has small magnetic deltas in northern trailing penumbrae. There are many spots, however, there's not much mature penumbra around any of them. C1 flares: C1.6 @ 02:05, C1.6 @ 12:06, C1.3 @ 15:06, C1.6 @ 17:02, C1.6 @ 17:43. C1.6 @ 20:02, C1.7 @ 20:25, C1.5 @ 20:54, C1.2 @ 22:56, C1.4 @ 23:38, C1.4 @ 23:44 UT
Region 13328 [N09W16] decayed slowly and quietly.
New region 13329 [N23E42] emerged on June 5 and was numbered by SWPC the following day as slow development continued. The region has C and maybe minor M class flare potential.
New region 13330 [N18E28] emerged on June 5 and developed slowly with SWPC numbering the region the next day.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S8610 [N29W23] was quiet and stable.
S8617 [N11E24] was quiet and stable.
S8625 [S28E01] was quiet and stable.
S8629 [N10E58] was quiet and stable.
New region S8632 [S22E76] rotated into view with a large, mature spot. C1 flares: C1.6 @ 20:48, C1.5 @ 21:02 UT
New region S8633 [S23W36] emerged before noon, then decayed slowly.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.1 01:03   13327 GOES16  
C2.8 03:19 behind southwest limb   GOES16 LDE
C4.5 04:33   13327 GOES16  
C4.1 05:22   13327 GOES16  
C4.2 05:30   13327 GOES16  
C5.6 08:41   13327 GOES16  
C6.3 09:14   13327 GOES16  
C4.0 09:44   13327 GOES16  
C4.6 09:49   13323 GOES16  
C2.4 17:21   13327 GOES16  
C2.1 18:32   13327 GOES16  
C7.5 19:00   13327 GOES16  
C2.2 19:30   13327 GOES16  

Coronal mass ejections (CMEs)

June 4-6: 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 7-9.

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
13320 2023.05.28
2023.05.29
2 7 2 N10W35 0020 HSX HAX area: 0040
13321 2023.05.29
2023.05.30
7 19 10 S14W25 0190 HSX CHO

area: 0320

S8606 2023.05.29       N11W31          
S8610 2023.05.30   1   N29W23 0002   AXX  
13324 2023.05.30
2023.06.02
  10 4 N11W66 0025   BXO location: N14W64
13323 2023.05.30
2023.05.31
20 61 31 S08W14 0300 EKI EAI

beta-gamma

location: S08W03

SWPC location is way off

S8613 2023.06.01       S08W35            
13325 2023.06.01
2023.06.02
1 2 2 N09W60 0010 HSX AXX location: N09W59
13326 2023.06.02
2023.06.02
1 8 1 N26E23 0070 HSX CSO location: N25E25

area: 0140

S8617 2023.06.02   3 3 N11E24 0012   BXO  
13327 2023.06.03
2023.06.04
16 61 33 S15E42 0300 DKI EAI beta-gamma-delta

area: 0310

S8623 2023.06.03       N15W14          
S8624 2023.06.03       S03W46            
S8625 2023.06.03   3 2 S28E01 0007   BXO  
S8626 2023.06.04       N16W58          
13328 2023.06.04
2023.06.05
  4   N11W17 0005   BXO

location: N09W16

S8629 2023.06.04   3 1 N10E58 0010   BXO  
13330 2023.06.05
2023.06.06
2 11 9 N18E27 0010 BXO DRO area: 0030

location: N18E28

13329 2023.06.05
2023.06.06
4 21 12 N25E42 0040 DAO DAI location: N23E42

area: 0130

S8632 2023.06.06   2 2 S22E76 0260   CHO    
S8633 2023.06.06   1   S23W36 0001   AXX    
Total spot count: 53 217 112  
Sunspot number: 133 377 242  (total spot count + 10 * number of spotted regions)
Weighted SN: 98 265 160  (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): 146 207 194  

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
2023.06 166.7 (1)   26.5 (2A) / 132.7 (2B) / 162.5 (2C) (134.3 projected, +3.1) (6.0)
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.