Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 8, 2023 at 07:55 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 (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 (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 active on July 7, likely under the influence of effects from CH1158. Solar wind speed at SOHO ranged between 452 and 548 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 161.4 - increasing 0.2 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 146.64. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 17 (STAR Ap - based on the mean of three hour interval ap indices: 17.0). Three hour interval K indices: 32343243 (planetary), 32444333 (Boulder), 53244555 (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: 310) and in 12 active regions using 1K resolution (SN: 192) SDO/HMI images.

Region 13355 [S17W67] decayed slowly and quietly.
Region 13358 [S12W21] decayed slowly and quietly.
Region 13359 [S21W24] decayed slowly and was mostly quiet. C1 flares: C1.7 @ 05:57 UT
Region 13360 [N22W19] was mostly quiet and stable. C1 flares: C1.8 @ 16:35 UT
Region 13361 [N23E02] became more complicated again as a magnetic delta formed in the eastern part of intermediate penumbra. C and M flares are likely. C1 flares: C1.8 @ 23:46 UT
Region 13362 [S09E35] was quiet and stable.
Region 13363 [S21E59] was mostly quiet and stable. M flares are possible.
Region 13364 [N23E45] displayed signs of decay and was quiet.
New region 13365 [S37W19] emerged on July 5 and was numbered by SWPC 2 days later.
New region 13366 [S10W10] was first observed with spots on June 30. New flux emerged on July 7 and the region developed quickly.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S8725 [S19W03] decayed slowly and quietly.
S8739 [N07E07] reemerged with tiny spots.
New region S8742 [N09E30] emerged within CH1159 causing the coronal hole to shrink considerably. Only tiny spots are visible.
New region S8743 [N24E18] was observed with tiny spots in an old plage area.
New region S8744 [S05W17] emerged with a tiny spot.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
M4.0/2B 06:29 S22W15 13359 GOES16  
C4.2 07:32   13359 GOES16  
C2.0 13:07   13361 GOES16  
C2.3 13:58   13361 GOES16 incorrectly attributed to AR 13363 by SWPC
C2.6 17:32   13366 GOES16  
C2.7 18:19   13361 GOES16  
C2.3 22:09   13361 GOES16  

Coronal mass ejections (CMEs)

July 5-7: 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 northern hemisphere coronal hole (CH1158) was Earth facing on July 4-5. A recurrent trans equatorial coronal hole (CH1159) will likely rotate across the central meridian on July 9-11.

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

Quiet to active geomagnetic conditions are likely on July 8 due to effects from the July 4 CME and a high speed stream associated with CH1158. Quiet to unsettled is likely on July 9-11. Quiet to active is likely on July 12-13 due to effects from CH1159.

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
13355 2023.06.26
2023.06.27
  1 1 S15W70 0004   AXX

location: S17W67

13356 2023.06.29
2023.06.30
      S07W65           location: S08W53
13357 2023.06.30
2023.07.01
      S07W48         location: S07W45
13358 2023.06.30
2023.07.01
7 22 9 S13W23 0010 BXO BXI

location: S12W21

area: 0040

13359 2023.06.30
2023.07.01
11 20 9 S22W27 0210 DAO DAO

beta-gamma

location: S21W24

area: 0150

13366 2023.06.30
2023.07.07
10 33 12 S11W09 0020 DRI DAI area: 0190

location: S10W10

13360 2023.06.30
2023.07.01
4 7 4 N23W21 0020 CRO CRO

location: N22W19

area: 0030

S8721 2023.06.30       N17W40            
S8724 2023.07.02       N09W27            
S8725 2023.07.02   5   S19W03 0007   AXX  
S8726 2023.07.02       S37W27            
13361 2023.07.02
2023.07.04
17 42 24 N24E02 0240 EAC EAC

beta-gamma-delta

location: N23E02

area: 0380

S8730 2023.07.03       N18W11            
13362 2023.07.04
2023.07.05
1 2 1 S09E33 0050 HSX CSO location: S09E35

area: 0120

S8733 2023.07.04       N31E04            
13363 2023.07.05
2023.07.06
2 7 4 S21E56 0320 HKX CKO location: S21E59

area: 0890

S8735 2023.07.05       N18W48            
13364 2023.07.05
2023.07.06
3 8 4 N23E45 0020 CRO CRO  
13365 2023.07.05
2023.07.07
2 2 2 S36W21 0020 BXO CRO area: 0040

location: S37W19

S8739 2023.07.06   5 1 N07E07 0015   AXX    
S8741 2023.07.06       N46E25          
S8742 2023.07.07   2 1 N09E30 0004   BXO    
S8743 2023.07.07   3   N24E18 0004   AXX    
S8744 2023.07.07   1   S05W17 0003   AXX    
Total spot count: 57 160 72  
Sunspot number: 147 310 192  (total spot count + 10 * number of spotted regions)
Weighted SN: 91 199 111  (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): 162 171 154  

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  164.2 (1)   29.0 (2A) / 128.6 (2B) / 169.4 (2C) (135.4 projected, -0.5) (5.3)
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.