Solar Terrestrial Activity Report

Activity chart

Last major update issued on February 23, 2023 at 04:40 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 (February 4, 2023)
Solar cycle Solar cycles 23-25 (February 1, 2023) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (February 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 (February 1, 2023) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (February 1, 2023) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (January 21, 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 on February 22. Solar wind speed at SOHO ranged between 372 and 507 km/sec. The high latitude magnetometer at Andenes recorded quiet to minor storm levels. What appears to be a solar wind transient was observed arriving at DSCOVR near 23:25 UT and is causing active to minor storm conditions early on February 23.

Solar flux density measured at 20h UT on 2.8 GHz was 151.9 - increasing 1.3 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 134.18). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.1). Three hour interval K indices: 20122222 (planetary), ******** (Boulder), 40112254 (Andenes).

The background x-ray flux was at the class C1 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 9 active regions using 2K resolution (SN: 216) and in 7 active regions using 1K resolution (SN: 145) SDO/HMI images.

Region 13229 [N25W05] decayed slowly and quietly. The region still has weak polarity intermixing.
Region 13230 [S22E20] gained spots while the main penumbra displayed signs of decay.
Region 13231 [N20W78] decayed slowly and was mostly quiet. C1 flares: C1.7 @ 20:05 UT
Region 13233 [N17W21] decayed slowly and quietly.
Region 13234 [N25E46] gained area and has a magnetic delta in the trailing spot section. M flares are possible. C1 flares: C1.5 @ 02:15, C1.8 @ 03:31, C1.9 @ 06:34, C1.5 @ 07:16, C1.8 @ 07:53, C1.8 @ 08:40, C1.7 @ 11:41, C1.6 @ 18:08 UT

Spotted regions not observed (or interpreted differently) by SWPC:
S8286 [S09W10] developed slowly and quietly.
S8295 [S23W11] decayed slowly and quietly.
New region S8302 [N19E23] emerged with several spots.
New region S8303 [S24E01] was observed with tiny spots in an old plage area.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C7.1 00:18   13234 GOES16  
C2.1 01:15   13231 GOES16 attributed to AR 13226 by SWPC
C7.1 02:48   13234 GOES16  
C2.9 04:16 N26E60 13234 GOES16  
M1.4 05:12   13234 GOES16 LDE
C5.7 05:52   13229 GOES16  
C2.6 08:02 N27E57 13234 GOES16  
C2.4 10:17   13230 GOES16  
C3.2 10:27   13234 GOES16 incorrectly attributed to AR 13230 by SWPC
C3.0 12:37   13234 GOES16  
C3.2 12:54   13234 GOES16  
C2.4 13:18   13230 GOES16  
M2.6 13:50 N27E57 13234 GOES16  
C3.2 15:02   13234 GOES16  
C2.2 16:24   13229 GOES16 simultaneous flare in AR 13234
C2.6 16:54   13234 GOES16  
C2.2 21:55   13230 GOES16  
C2.8 23:01   13234 GOES16  

Coronal mass ejections (CMEs)

February 20-22: 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 trans equatorial coronal hole (CH1132) will likely be Earth facing February 24-25.

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 minor storm conditions are likely on February 23 becoming quiet to unsettled on February 24-25.

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
13220 2023.02.09
2023.02.09
1     S13W96 0030 HSX     rotated out of view

location: S13W93

13226 2023.02.12
2023.02.13
1     N12W90 0080 HSX    

rotated out of view

13227 2023.02.12
2023.02.13
      S03W90           location: S04W80
13231 2023.02.13
2023.02.19
2 5 4 N20W78 0020 CRO CRO area: 0030
13229 2023.02.16
2023.02.16
17 37 21 N25W06 0200 ESI EAI beta-gamma
S8286 2023.02.17   6 3 S09W10 0015   BXO  
13230 2023.02.17
2023.02.18
7 19 14 S22E18 0120 DSO DAI area: 0260
S8288 2023.02.17       N20W47            
S8289 2023.02.18       S17W47            
13233 2023.02.18
2023.02.20
  5 1 N14W28 0010   BXO location: N17W21
S8291 2023.02.18       N28W57            
S8295 2023.02.19   1   S23W11 0002   AXX  
S8298 2023.02.20       N14E19          
13234 2023.02.20
2023.02.20
12 39 27 N25E47 0300 EKC EAC beta-delta

area: 0500

location: N25E46

S8301 2023.02.21       S12E37          
S8302 2023.02.22   11 5 N19E23 0030   CRI    
S8303 2023.02.22   3   S24E01 0006   BXO    
Total spot count: 40 126 75  
Sunspot number: 100 216 145  (total spot count + 10 * number of spotted regions)
Weighted SN: 71 147 96  (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): 110 119 116  

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 (solar max) 7.88
2017.09 91.3 92.3 43.6 18.2 (-1.3) 18.22
(cycle 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
2021.07 81.0 83.6 34.3 31.4 (+3.8) 5.51
2021.08 77.7 79.7 22.0 35.4 (+4.0) 6.19
2021.09 87.0 88.2 51.3 40.2 (+4.8) 6.33
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 77.2 (+4.2) 7.48
2022.06 116.1 119.8 70.3 80.9 (+3.7) 8.20
2022.07 125.4 129.5 91.4 86.5 (+5.6) 9.51
2022.08 114.2 117.1 74.6 (92.4 projected, +5.9) 10.92
2022.09 135.1 136.5 96.0 (97.4 projected, +5.0) 12.18
2022.10 133.5 132.7 95.4 (100.5 projected, +3.1) 11.16
2022.11 123.4 120.7 77.6 (103.4 projected, +2.9) 9.33
2022.12 147.9 143.4 113.1 (108.2 projected, +4.8) 10.99
2023.01 182.4 176.6 143.6 (114.2 projected, +6.0) 8.73
2023.02 169.9 (1)   99.3 (2A) / 126.4 (2B) / 146.9 (2C) (119.2 projected, +5.0) (10.7)
2023.03       (122.3 projected, +3.1)  
2023.04       (127.7 projected, +5.4)  
2023.05       (133.5 projected, +5.8)  
2023.06       (136.8 projected, +3.3)  
2023.07       (136.3 projected, -0.5)  
2023.11       (142.5 projected max SC25)  

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: SIDC-SILSO.

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.