Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 15, 2023 at 10:20 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 (July 6, 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 (July 10, 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 July 14. Solar wind speed at SOHO ranged between 320 and 433 km/sec. The high latitude magnetometer at Andenes recorded unsettled to minor storm levels. A solar wind shock was observed at SOHO at 15:17 UT, the likely arrival of the July 11 CME.

Solar flux density measured at 20h UT on 2.8 GHz was 180.6 - increasing 16.5 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 147.32. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 20 (STAR Ap - based on the mean of three hour interval ap indices: 20.3). Three hour interval K indices: 34323454 (planetary), 34433333 (Boulder), 45434443 (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 10 active regions using 2K resolution (SN: 214) and in 8 active regions using 1K resolution (SN: 134) SDO/HMI images.

Region 13362 [S08W58] decayed slowly and quietly.
Region 13363 [S22W32] decayed slowly and produced several flares. The main penumbra still has two magnetic delta structures, one in the north and one in the southeast. A major flare is possible. C1 flares: C1.7 @ 21:38, C1.8 @ 17:24 UT
Region 13367 [N10W69] decayed slowly and was mostly quiet.
Region 13370 [S16E07] decayed slowly and was mostly quiet.
Region 13371 [S16E22] was quiet and stable.
Region 13372 [N22E40] has 3 small magnetic delta structures in the trailing penumbra and was somewhat unstable. C1 flares: C1.6 @ 23:15 UT
New region 13373 [N08E68] rotated into view on July 13 and was numbered by SWPC the next day. The region decayed slowly with the main penumbra splitting into smaller penumbrae. C1 flares: C1.5 @ 16:09, C1.9 @ 20:32 UT
New region 13374 [S08E68] rotated into view on July 13 with SWPC numbering the region the following day.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S8752 [N17W07] reemerged with a tiny spot.
New region S8766 [N27E22] emerged with a tiny spot.

CMEs were observed after the M1 flare in AR 13363 at 09:36 UT on July 14 and after the M2.9 flare in the same region at 07:40 on July 15. Initial analysis indicate that the CMEs are not Earth directed.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C3.0 00:09 behind southwest limb 13368? GOES16  
C5.8 00:31 N24E49 13372 GOES16 simultaneous flare in AR 13363
C2.4 01:50   13363 GOES16  
C2.2 04:24   13363 GOES16  
C2.1 06:13 behind southwest limb 13368? GOES16  
C2.3 06:29   13374 GOES16  
C2.6 09:20   13361 GOES16  
M1.0 09:36   13363 GOES16  
C2.1 10:57   13363 GOES16  
C7.2 11:51 N25E51 13372 GOES18  
C7.6 12:02   13372 GOES18  
C3.3 12:31   13363 GOES18  
C3.5 13:33 S24W24 13363 GOES18  
C4.9 14:05 behind northeast limb   GOES18  
C2.0 15:32   13363 GOES18  
C8.8 18:44   13370 GOES18  
C3.6 19:50   13370 GOES18  
C3.1 20:16   13363 GOES18  

Coronal mass ejections (CMEs)

July 12-14: 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]

No obvious coronal holes are currently in a potentially geoeffective position.

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 to fair.

Forecast

The geomagnetic field is expected to be quiet to active on July 15-16 due to CME and coronal hole effects. Mostly quiet conditions are likely on July 17.

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
13361 2023.07.02
2023.07.04
1     N24W89 0040 HSX     rotated out of view
13362 2023.07.04
2023.07.05
1 2 1 S08W59 0010 AXX AXX area: 0006
13363 2023.07.05
2023.07.06
16 36 17 S22W34 0780 DKO DKC beta-delta

location: S22W32

area: 0940

13364 2023.07.05
2023.07.06
      N25W52        

 

13367 2023.07.07
2023.07.08
9 15 8 N10W69 0170 DAO EAI  
S8746 2023.07.08       S29W55            
13370 2023.07.09
2023.07.10
4 9 4 S15E08 0010 BXO BXO

location: S16E07

S8748 2023.07.09       N31W46            
13371 2023.07.10
2023.07.11
2 9 4 S15E20 0030 HAX HAX area: 0070

location: S16E22

S8752 2023.07.10   1   N17W01 0003   AXX    
S8753 2023.07.10       S29E14            
13372 2023.07.11
2023.07.11
11 31 14 N24E39 0770 EKO FKC

beta-delta

location: N22E40

area: 1210

S8755 2023.07.11       N51W31            
S8756 2023.07.11       S15W02          
S8757 2023.07.11       N21W24            
S8758 2023.07.12       N26E03            
S8759 2023.07.12       S01W21            
S8761 2023.07.13       N22W13          
13373 2023.07.13
2023.07.14
6 9 5 N08E66 0120 DAO DAO  
13374 2023.07.13
2023.07.14
1 2 1 S09E69 0030 HSX HAX  
S8764 2023.07.13       N17E14          
S8765 2023.07.13       S00E36          
S8766 2023.07.14   1   N27E22 0003   AXX    
Total spot count: 51 115 54  
Sunspot number: 141 215 134  (total spot count + 10 * number of spotted regions)
Weighted SN: 96 165 94  (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): 155 118 107  

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
2021.12 103.0 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  176.5 (1)   69.2 (2A) / 153.4 (2B) / 171.5 (2C) (135.4 projected, -0.5) (7.2)
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.