Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 1, 2023 at 07:15 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 (July 1, 2023) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (July 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 (July 1, 2023) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (July 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 30. Solar wind speed at SOHO ranged between 414 and 599 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 158.6 - decreasing 6.3 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 145.51. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 7 (STAR Ap - based on the mean of three hour interval ap indices: 7.0). Three hour interval K indices: 31223200 (planetary), 32333211 (Boulder), 54233211 (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: 261) and in 12 active regions using 1K resolution (SN: 190) SDO/HMI images.

Region 13341 [S16W73] decayed slowly and quietly.
Region 13348 [S34W38] quiet and stable.
Region 13354 [N15W28] decayed losing area and spots. In the northern part of the leading spot section a fairly strong magnetic delta formed. An X class event is possible. C1 flare: C1.6 @ 01:25, C1.5 @ 04:05, C1.6 @ 04:22, C1.3 @ 05:29, C1.8 @ 06:16, C1.8 @ 09:09, C1.9 @ 11:21, C1.6 @ 12:38, C1.9 @ 13:08, C1.7 @ 16:57, C1.9 @ 17:47, C1.7 @ 19:15, C1.7 @ 19:47 UT
Region 13355 [S16E22] decayed slowly and quietly.
New region 13356 [S07E38] emerged on June 29 and was numbered the next day by SWPC.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S8709 [N15W76] developed slowly and was mostly quiet. C1 flares: C1.6 @ 00:18 UT
New region S8714 [S06E47] emerged with several tiny spots.
New region S8715 [S12E73] rotated into view with several spots. C1 flares: C1.5 @ 01:50, C1.3 @ 06:36, C1.7 @ 14:10, C1.9 @ 18:24 UT
New region S8716 [S21E70] emerged with tiny spots.
New region S8717 [S10E83] rotated into view with a tiny spot.
New region S8718 [N14E35] emerged with tiny spots.
New region S8719 [N23E73] rotated into view with a small spot.
New region S8720 [N15E05] was observed with tiny spots in an old plage area.
New region S8721 [N17E51] emerged with a tiny spot.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C3.1 07:31 southeast limb S8717 GOES16 incorrectly attributed to AR 13354 by SWPC
C2.8 08:07   S8715 GOES16  
C2.2 08:19   13354 GOES16  
C5.7/1F 10:10   13354 GOES16  
C2.9 12:47   13340 GOES16  
C4.2 13:54 N17W30 13354 GOES16  
C2.1 15:41   S8715 GOES16 simultaneous flare in AR 13354
C3.7 18:57   13354 GOES16  
C2.8 19:07   13340 GOES16  

Coronal mass ejections (CMEs)

June 28-30: 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 small southern hemisphere coronal hole (CH1156) rotated across the central meridian on June 26-27. Another small southern hemisphere coronal hole (CH1157) was Earth facing on June 30.

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.

Forecast

Quiet geomagnetic conditions are likely on July 1-2. Quiet to unsettled is possible on July 3-4 due to weak effects from CH1157.

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
13341 2023.06.18
2023.06.19
1 2 1 S15W75 0010 AXX AXX

location: S16W73

area: 0006

13345 2023.06.19
2023.06.20
1     N06W78 0010 HRX    

spotless

location: N08W75

13350 2023.06.20
2023.06.23
      S11W59           location: S09W53
S8689 2023.06.21       N15W53            
13348 2023.06.21
2023.06.23
  2   S33W47 0003   AXX location: S34W38
13349 2023.06.22
2023.06.23
      N08W59           location: N09W54
13351 2023.06.22
2023.06.23
      N21W36         location: N22W34
13354 2023.06.22
2023.06.26
30 62 43 N13W30 0880 FKC FKC beta-gamma-delta

location: N15W28

S8704 2023.06.24       N08W46            
13355 2023.06.26
2023.06.27
3 11 3 S16E14 0030 HSX HAX area: 0050

location: S16E22

S8707 2023.06.27       N20W08            
S8709 2023.06.29   5 2 N15W76 0015   CRO  
13356 2023.06.29
2023.06.30
2 9 4 S08E38 0010 BXO BXO  
S8711 2023.06.29       N14E36          
S8712 2023.06.29       S12E09          
S8713 2023.06.29       S12W02          
S8714 2023.06.30   7 6 S06E47 0020   CRI    
S8715 2023.06.30   8 4 S12E73 0090   CAO    
S8716 2023.06.30   3 2 S21E70 0015   CRO    
S8717 2023.06.30   1 1 S10E83 0003   AXX    
S8718 2023.06.30   2 1 N14E35 0005   AXX    
S8719 2023.06.30   1 1 N23E73 0006   HRX    
S8720 2023.06.30   7 2 N15E05 0010   BXO    
S8721 2023.06.30   1   N17E51 0001   AXX    
Total spot count: 37 121 70  
Sunspot number: 87 261 190  (total spot count + 10 * number of spotted regions)
Weighted SN: 55 153 102  (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): 96 144 152  

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
2022.12 147.9 143.4 112.8 106.6 (+5.6) 10.99
2023.01 182.4 176.6 143.6 (113.7 projected, +6.1) 8.73
2023.02 167.2 163.2 110.9 (118.5 projected, +4.8) 14.48
(current
SC25 peak)
2023.03 157.2 155.6 122.6 (121.6 projected, +3.1) 14.42
2023.04 145.4 146.4 96.4 (127.0 projected, +5.4) 13.40
2023.05 155.6 159.2 137.9 (132.7 projected, +5.7) 10.67
2023.06 161.7 166.8 163.4 (135.9 projected, +3.2) 8.9
2023.07  (1)   (2A/2B) / 174.9 (2C) (135.4 projected, -0.5) ()
2023.08       (136.4 projected, +1.0)  
2023.09       (139.8 projected, +3.4)  
2023.10       (141.6 projected, +1.8)  
2023.11       (144.2 projected max SC25, +2.6)  
2023.12       (143.4 projected, -0.1)  
2024.01       (140.1 projected, -3.3)  

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.