Solar Terrestrial Activity Report

Activity chart

Last major update issued on February 26, 2023 at 08:10 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 to unsettled on February 25. Solar wind speed at SOHO ranged between 348 and 449 km/sec. The high latitude magnetometer at Andenes recorded quiet to minor storm levels.

Solar flux density measured at 18h UT on 2.8 GHz was 152.4 - increasing 15.4 over the previous solar rotation (The measurement at 20h UT was flare enhanced and discarded). (Centered 1 year average SF at 1 AU - 183 days ago: 134.66). The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 9.6). Three hour interval K indices: 11222333 (planetary), ******** (Boulder), 10222453 (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 14 active regions using 2K resolution (SN: 330) and in 10 active regions using 1K resolution (SN: 201) SDO/HMI images.

Region 13229 [N26W48] decayed slowly but still managed to produce a major flare. C1 flare: C1.2 @ 13:21 UT
Region 13230 [S22W20] decayed slowly and quietly.
Region 13234 [N24E04] developed another magnetic delta in the central parts of the region. A major flare is possible.
Region 13235 [N19W15] still has a small magnetic delta. A minor M class flare is possible.
Region 13236 [S26W05] has a magnetic delta structure in a central northern penumbra. M class flares are possible. C1 flares: C1.1 @ 11:17, C1.4 @ 12:29, C1.3 @ 13:35, C1.5 @ 13:41 UT
Region 13237 [S12E11] decayed slowly and quietly.

Spotted regions not observed (or interpreted differently) by SWPC:
S8295 [S23W52] reemerged with a few spots.
S8307 [N13W08] decayed slowly and quietly.
S8308 [S17E16] was quiet and stable.
New region S8309 [N13E24] emerged with tiny spots.
New region S8310 [S20E38] was observed with tiny spots in an old plage area.
New region S8311 [S17E49] was observed with tiny spots in an old plage area.
New region S8312 [S38W23] emerged with a tiny spot at a high latitude.
New region S8313 [N18E35] emerged with a tiny spot.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C3.2 00:46   13234 GOES16  
C2.1 03:09   13234 GOES16  
C8.1 04:22   13229 GOES16 weak type II radio sweep
C2.5 07:15   13229 GOES16  
C2.1 11:48   13236 GOES16  
C2.2 15:09   13236 GOES16  
M1.0 15:40   13236 GOES16  
M6.3/3N 19:30 N26W43 13229 GOES16 very long duration flare. Wide full halo CME
moderate fast type II radio sweep
proton event (current peak 10 MeV: 58 pfu @ 04:40 UT on Feb.26)

Coronal mass ejections (CMEs)

February 23: No obviously Earth directed CMEs were observed.
February 24: A fast asymmetric full halo CME was observed after the M3 flare in AR 13229. The CME could reach Earth sometime between late on February 26 and noon on February 27.
February 25: A fast asymmetric full halo CME was observed after the M6 flare in AR 13229. The CME could reach Earth sometime between noon and midnight on February 27.

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 be Earth facing on 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 active geomagnetic conditions are likely on February 26. The February 24 CME could reach Earth between late on February 26 and noon on February 27 and cause unsettled to major storm conditions. The February 25 CME could reach Earth between noon and midnight on February 27 and cause unsettled to severe storm conditions. On February 27-28 effects from CH1132 could contribute further to the disturbed geomagnetic field.

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
13229 2023.02.16
2023.02.16
12 16 10 N25W46 0150 ESO ESO beta-gamma

area: 0110

location: N26W48

S8286 2023.02.17       S10W50            
13230 2023.02.17
2023.02.18
11 17 7 S22W22 0120 CSO HAX location: S22W20
13233 2023.02.18
2023.02.20
      N14W70           location: N18W58
S8295 2023.02.19   7 3 S23W52 0015   CRO    
S8298 2023.02.20       N14W20            
13234 2023.02.20
2023.02.20
25 64 40 N25E05 0580 EKC FKC beta-gamma-delta

area: 0870

location: N24E04

S8301 2023.02.21       S12W02            
13235 2023.02.22
2023.02.23
6 14 9 N19W20 0040 DAO DRI beta-delta

location: N19W15

area: 0060

SWPC copied spot count, area, classification from the previous day with no changes for any region except AR 13237

S8303 2023.02.22       S25W37          
13236 2023.02.23
2023.02.23
14 52 28 S28W09 0080 DAI DAC beta-delta

location: S26W05

area: 0270

 

13237 2023.02.23
2023.02.24
1 2 1 S12E09 0010 AXX HRX area: 0015

location: S12E11

S8306 2023.02.23       N12E22            
S8307 2023.02.24   2 1 N13W08 0005   AXX  
S8308 2023.02.24   4   S17E16 0005   BXO  
S8309 2023.02.25   3 1 N13E24 0007   BXO    
S8310 2023.02.25   4 1 S20E38 0010   BXO    
S8311 2023.02.25   3   S17E49 0003   AXX    
S8312 2023.02.25   1   S38W23 0002   AXX    
S8313 2023.02.25   1   N18E35 0001   AXX    
Total spot count: 69 190 101  
Sunspot number: 129 330 201  (total spot count + 10 * number of spotted regions)
Weighted SN: 99 224 135  (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): 142 182 161  

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
2023.02 168.1 (1)   112.4 (2A) / 125.9 (2B) / 147.7 (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.