Solar Terrestrial Activity Report

Activity chart

Last major update issued on February 27, 2023 at 04:55 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 (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 major storm on February 26. Solar wind speed at SOHO ranged between 412 and 761 km/sec. The high latitude magnetometer at Andenes recorded quiet to major storm levels. A solar wind shock was recorded at 18:43 UT at DSCOVR, the arrival of the February 24 CME.

Solar flux density measured at 20h UT on 2.8 GHz was 159.0 - increasing 23.1 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 134.83). The Potsdam WDC planetary A index was 26 (STAR Ap - based on the mean of three hour interval ap indices: 25.8). Three hour interval K indices: 33343256 (planetary), ******** (Boulder), 44423346 (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 10 active regions using 2K resolution (SN: 242) and in 9 active regions using 1K resolution (SN: 173) SDO/HMI images.

Region 13229 [N26W61] decayed slowly and quietly.
Region 13230 [S22W32] decayed slowly and quietly.
Region 13234 [N24W10] gained a weak magnetic delta in the northern part of the large leading penumbra. A major flare is possible. C1 flares: C1.8 @ 22:43, C1.6 @ 23:52 UT
Region 13235 [N19W29] decayed slowly and was mostly quiet.
Region 13236 [S27W18] decayed slowly and was mostly quiet.
Region 13237 [S13W04] decayed slowly and quietly.

Spotted regions not observed (or interpreted differently) by SWPC:
S8295 [S22W67] decayed slowly and quietly.
S8311 [S20E49] was quiet and stable.
New region S8314 [N09E78] rotated into view with a mature spot.
New region S8315 [S08E01] emerged with tiny spots.

A C1.9 flare was recorded at 20:53 UT from a location behind the northeast limb.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C3.1 08:16   13234 GOES16 simultaneous flare in AR 13236
C2.6 08:56   S8314 GOES16  
C5.5 12:00   13235 GOES16  
C2.7 12:51   13234 GOES16  
C2.8 13:07   13234 GOES16  
C3.2 13:35   13234 GOES16  
C2.0 14:56   13234 GOES16  
C2.8 19:23   13234 GOES16  
C2.0 21:06   13234 GOES16  
C2.5 21:18   13234 GOES16  

Coronal mass ejections (CMEs)

February 24: A fast asymmetric full halo CME was observed after the M3 flare in AR 13229. The CME reached Earth late on February 26.
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.
February 26: 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.

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

Unsettled to major storm conditions are likely on February 27 due to CME effects, an isolated severe storm interval is possible. 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. March 1 could see quiet to active conditions.

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
7 7 5 N25W60 0130 ESO DAO

area: 0080

location: N26W61

13230 2023.02.17
2023.02.18
10 7 2 S22W36 0110 CSO HAX location: S22W32

area: 0070

13233 2023.02.18
2023.02.20
      N14W84           location: N18W58
S8295 2023.02.19   4 3 S22W67 0010   BXO  
S8298 2023.02.20       N14W33            
13234 2023.02.20
2023.02.20
25 62 38 N25W09 0580 EKC FKC beta-gamma-delta

area: 0760

location: N24W10

S8301 2023.02.21       S12W15            
13235 2023.02.22
2023.02.23
5 7 2 N19W34 0030 CAO DRO

location: N19W29

S8303 2023.02.22       S25W50            
13236 2023.02.23
2023.02.23
11 43 27 S28W23 0070 DAI DAI beta-gamma

location: S27W18

area: 0220

 

13237 2023.02.23
2023.02.24
2 5 2 S12W05 0010 BXO BXO

location: S13W04

S8306 2023.02.23       N12E09            
S8307 2023.02.24       N13W21          
S8308 2023.02.24       S17E03          
S8309 2023.02.25       N13E11          
S8310 2023.02.25       S20E25          
S8311 2023.02.25   2   S20E49 0002   BXO  
S8312 2023.02.25       S38W36          
S8313 2023.02.25       N18E22          
S8314 2023.02.26   1 1 N09E78 0120   HSX    
S8315 2023.02.26   4 3 S08E01 0012   BXO    
Total spot count: 60 142 83  
Sunspot number: 120 242 173  (total spot count + 10 * number of spotted regions)
Weighted SN: 90 175 116  (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): 132 133 138  

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
2023.02 167.7 (1)   116.7 (2A) / 125.6 (2B) / 149.2 (2C) (119.2 projected, +5.0) (11.3)
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.