Solar Terrestrial Activity Report

Activity chart

Last major update issued on February 28, 2023 at 07:05 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 at minor to severe storm levels on February 27 due to CME effects. Solar wind speed at SOHO ranged between 568 and 941 km/sec. The high latitude magnetometer at Andenes recorded minor to major storm levels. The February 25 CME was observed reaching DSCOVR at 10:20 UT.

Solar flux density measured at 20h UT on 2.8 GHz was 161.2 - increasing 24.2 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 135.00). The Potsdam WDC planetary A index was 90 (STAR Ap - based on the mean of three hour interval ap indices: 89.5). Three hour interval K indices: 56776766 (planetary), ******** (Boulder), 66655666 (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 15 active regions using 2K resolution (SN: 288) and in 11 active regions using 1K resolution (SN: 188) SDO/HMI images.

Region 13229 [N26W76] decayed quickly and was mostly quiet. C1 flares: C1.6 @ 20:43 UT
Region 13230 [S22W45] decayed slowly and quietly.
Region 13234 [N23W24] developed slowly and has multiple magnetic delta structures. A major flare is possible. C1 flares: C1.3 @ 00:33, C1.3 @ 02:45, C1.3 @ 06:47, C1.4 @ 13:12 UT UT
Region 13235 [N19W43] decayed slowly and quietly.
Region 13236 [S27W31] decayed further and was quiet.
Region 13237 [S13W14] decayed slowly and quietly.
New region 13238 [N09E64] rotated into view on February 26 and was numbered by SWPC the next day.

Spotted regions not observed (or interpreted differently) by SWPC:
S8295 [S22W79] decayed slowly and quietly.
S8308 [S22W06] reemerged with tiny spots.
S8310 [S27E22] reemerged with tiny spots.
S8311 [S24E40] was quiet and stable.
S8315 [S08W12] developed slowly and quietly.
New region S8316 [N18E08] emerged as a bipolar group before noon, then decayed slowly.
New region S8317 [N33E85] rotated partly into view and could be capable of major flaring.
New region S8318 [S29E36] was observed with tiny spots in an old plage area.

AR S8319 behind the northeast limb produced a C1.6 flare at 22:01 UT.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C4.5 10:22   13234 GOES16  
C2.1 15:19   13234 GOES16  
C2.5 16:33   13234 GOES16  
C2.1 17:53   13234 GOES16  
C2.1 23:21   13230 GOES16  
C2.1 23:30   13229 GOES16  

Coronal mass ejections (CMEs)

February 25: A fast asymmetric full halo CME was observed after the M6 flare in AR 13229. The CME reached Earth near 11h UT on February 27
February 26-27: 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) was Earth facing on February 24-25. Due to the strong solar storms overtaking the associated high speed stream, it will not be possible to observe any disturbance during this solar rotation.
A recurrent northern hemisphere coronal hole (CH1133) will likely rotate across the central meridian on February 28 - March 2.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle and high latitudes is very poor. Propagation on long distance northeast-southwest paths is poor.

Forecast

Unsettled to major storm conditions are likely on February 28 due to CME effects. March 1-2 could see quiet to unsettled conditions. Effects from CH1133 could cause unsettled to minor storm conditions on March 3-4.

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
3* 4 3 N26W74 0040 CSO HRX

location: N26W76

*SWPC reported the spot count as 53 due to a typo

13230 2023.02.17
2023.02.18
3 9 2 S23W46 0030 CRO CRO location: S22W45
S8295 2023.02.19   2 1 S22W79 0006   AXX  
S8298 2023.02.20       N14W46            
13234 2023.02.20
2023.02.20
40 68 45 N25W22 0750 FKC FKC beta-gamma-delta

location: N23W24

S8301 2023.02.21       S12W28            
13235 2023.02.22
2023.02.23
2 4   N19W45 0010 BXO BXO

location: N19W43

area: 0006

13236 2023.02.23
2023.02.23
20 27 17 S27W32 0140 CSO DSI

 

13237 2023.02.23
2023.02.24
3 3 2 S08W12 0010 BXO BXO

real location: S13W17

SWPC observers were confused by the spots of AR S8315 and changed the location to that group

S8306 2023.02.23       N12W04            
S8307 2023.02.24       N13W34            
S8308 2023.02.24   6 1 S22W06 0010   BXO    
S8309 2023.02.25       N13W02            
S8310 2023.02.25   2 1 S27E22 0003   AXX    
S8311 2023.02.25   2   S24E40 0003   BXO  
S8312 2023.02.25       S38W49            
S8313 2023.02.25       N18E09            
13238 2023.02.26
2023.02.27
1 1 1 N08E62 0050 HSX HSX location: N09E64

area: 0120

S8315 2023.02.26   7 5 S08W12 0030   DRO  
S8316 2023.02.27   1   N18E08 0001   AXX    
S8317 2023.02.27   1 1 N33E85 0160   HSX    
S8318 2023.02.27   1   S29E36 0002   AXX    
Total spot count: 72 138 78  
Sunspot number: 142 288 188  (total spot count + 10 * number of spotted regions)
Weighted SN: 100 172 112  (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): 156 158 150  

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
2023.02 167.5 (1)   121.8 (2A) / 126.3 (2B) / 150.6 (2C) (119.2 projected, +5.0) (14.2)
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.