Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 7, 2023 at 09:15 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 (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 unsettled on July 6. Solar wind speed at SOHO ranged between 391 and 551 km/sec. The high latitude magnetometer at Andenes recorded quiet to minor storm levels. Solar wind speed increased slightly after 21h UT and the geomagnetic field became more disturbed. This may have been the arrival of the high speed stream associated with CH1158.

Solar flux density measured at 20h UT on 2.8 GHz was 157.6 - decreasing 6.7 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 146.53. In comparison SC24 peaked on June 28, 2014 at 145.50). The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.1). Three hour interval K indices: 22233223 (planetary), 21244413 (Boulder), 43233435 (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 13 active regions using 2K resolution (SN: 269) and in 12 active regions using 1K resolution (SN: 185) SDO/HMI images.

Region 13355 [S15W55] decayed slowly and quietly.
Region 13357 [S07W32] decayed slowly and quietly.
Region 13358 [S13W07] decayed early in the day, then new flux emerged in the trailing polarity section. C1 flares: C1.5 @ 14:08 UT
Region 13359 [S21W11] displayed few changes and remains capable of M class flaring.
Region 13360 [N22W07] decayed slowly and was mostly quiet.
Region 13361 [N23E15] became less complex with no polarity intermixing observed late in the day.
Region 13362 [S09E49] was quiet and stable.
New region 13363 [S21E71] rotated into view on July 5 with a huge spot. While the region currently isn't magnetically complex, there is a chance of major flaring.
New region 13364 [N24E59] rotated into view on July 5 and was numbered the next day by SWPC.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S8717 [S10E02] decayed slowly and quietly.
S8725 [S20E08] decayed slowly and quietly.
S8738 [S37W07] developed slowly and quietly.
New region S8741 [N46E38] emerged with a tiny spot at a high latitude.

AR 13354 produced flares from behind the northwest limb. C1 flares: C1.9 @ 02:45 UT

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.3 03:25 N23E30 13361 GOES16  
C2.3 04:31   13359 GOES16  
C8.9/1N 04:45 N23E06 13360 GOES16  
C4.6 06:01   13359 GOES16  
C3.5 08:26 behind northwest limb 13354 GOES16  
C2.8 09:52 behind northwest limb 13354 GOES16  
C3.3 10:16   13359 GOES16 incorrectly attributed to AR 13361 by SWPC
M1.0 10:49 behind northwest limb 13354 GOES16  
C2.6 12:11 S21W04 13359 GOES16  
C2.8 12:43   13361 GOES16  
C2.5 13:13 behind northwest limb 13354 GOES16  
C2.7 23:50   13359 GOES16  

Coronal mass ejections (CMEs)

July 5-6: No obviously Earth directed CMEs were observed.
July 4: A filament eruption in the southeast quadrant was observed beginning near 02:30 UT and was associated with a partial halo CME. This CME could reach Earth on July 7.

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.

Forecast

Quiet to active geomagnetic conditions are likely on July 7-8 due to the July 4 CME and a high speed stream associated with CH1158. Quiet to unsettled is likely on July 9-10.

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
4 7 3 S15W59 0010 BXO CRO

location: S15W55

13356 2023.06.29
2023.06.30
      S07W50           location: S08W40
S8711 2023.06.29       N14W42            
13357 2023.06.30
2023.07.01
1 4 3 S07W35 0010 AXX AXX location: S07W32
13358 2023.06.30
2023.07.01
11 24 12 S11W15 0010 BXO DRI

location: S13W07

area: 0060

13359 2023.06.30
2023.07.01
10 26 11 S21W15 0240 DAO DAO

beta-gamma

location: S21W11

area: 0180

S8717 2023.06.30   6 2 S10E02 0015   BXO  
S8718 2023.06.30       N14W43            
13360 2023.06.30
2023.07.01
7 10 4 N22W06 0030 CRO CAO

location: N22W07

area: 0050

S8721 2023.06.30       N17W27            
S8724 2023.07.02       N09W14            
S8725 2023.07.02   6 2 S20E08 0010   AXX  
S8726 2023.07.02       S37W14            
13361 2023.07.02
2023.07.04
17 35 19 N22E17 0230 DAI EAI

location: N23E15

area: 0300

S8730 2023.07.03       N18W11            
13362 2023.07.04
2023.07.05
1 2 2 S10E47 0040 HSX HSX location: S09E49

area: 0120

S8733 2023.07.04       N31E17          
13363 2023.07.05
2023.07.06
1 4 2 S21E68 0390 HHX HKX location: S21E71

area: 0890

S8735 2023.07.05       N18W35          
13364 2023.07.05
2023.07.06
7 8 3 N24E59 0020 CRO CRO  
S8737 2023.07.05       N16W52          
S8738 2023.07.05   6 2 S37W07 0015   BXO  
S8741 2023.07.06   1   N46E38 0001   AXX    
Total spot count: 59 139 65  
Sunspot number: 149 269 185  (total spot count + 10 * number of spotted regions)
Weighted SN: 90 178 104  (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): 164 135 148  

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  164.7 (1)   23.6 (2A) / 122.2 (2B) / 170.9 (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.