Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 4, 2023 at 13:00 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 (March 3, 2023)
Solar cycle Solar cycles 23-25 (March 1, 2023) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (March 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 (March 1, 2023) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (March 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 active on March 3 under the influence of a very high speed stream from CH1133. Solar wind speed at SOHO ranged between 507 and 855 km/sec. The high latitude magnetometer at Andenes recorded quiet to major storm levels.

Solar flux density measured at 17h UT on 2.8 GHz was 175.7 - increasing 36.7 over the previous solar rotation. The measurement at 20h UT was discarded due to flare enhancement. (Centered 1 year average SF at 1 AU - 183 days ago: 135.67). The Potsdam WDC planetary A index was 22 (STAR Ap - based on the mean of three hour interval ap indices: 22.0). Three hour interval K indices: 44344244 (planetary), ******** (Boulder), 44444266 (Andenes).

The background x-ray flux was at the class C2 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 14 active regions using 2K resolution (SN: 239) and in 12 active regions using 1K resolution (SN: 162) SDO/HMI images.

Region 13234 [N23W81] produced another major flare as the group rotated to the northwest limb. A major flare is possible as there are still multiple magnetic deltas.
Region 13236 [S24W83] decayed slowly and was mostly quiet.
Region 13238 [N09E12] was quiet and stable.
Region 13239 [N32E29] was quiet and stable.
Region 13240 [S17E32] was quiet and stable.
Region 13241 [N28E43] was quiet and stable.
Region 13242 [N10E53] developed slowly and quietly.
New region 13243 [N18W35] emerged on March 1 and was numbered by SWPC 2 days later as the region developed slowly.
New region 13244 [S22W19] emerged on February 25 with SWPC numbering the region on March 3.
New region 13245 [S23E76] rotated partly into view on March 2 and was numbered the next day by SWPC.

Spotted regions not observed (or interpreted differently) by SWPC:
S8327 [S09E18] developed slowly and quietly.
New region S8330 [S17E64] emerged with tiny spots.
New region S8331 [S32E10] was observed with tiny spots in an old plage area.
New region S8332 [N27W02] emerged with a tiny spot.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C7.2 02:23 N06E65 13242 GOES16 LDE
C2.4 06:30   13234 GOES16  
C3.0 07:16   13234 GOES16  
C5.0 08:46 N22W73 13234 GOES16  
M3.3/1F 10:32   13234 GOES16  
C4.2 11:59   13242 GOES16  
C3.9 14:31   13242 GOES16  
C9.1 15:12   13242 GOES16  
C6.3 15:55   13242 GOES16  
X2.1/1B 17:52 N22W80 13234 GOES16 weak type II and IV radio sweeps
C8.0 19:21   13234 GOES16  
C3.1 21:18   13234 GOES16  
C3.2 22:27   13242 GOES16  
C3.1 23:19   13242 GOES16  
C3.5 23:28   13234 GOES16  

Coronal mass ejections (CMEs)

March 1-3: 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 trans equatorial coronal hole (CH1133) rotated across the central meridian on March 1-3.

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 conditions are likely on March 4-6 due to effects from CH1133, isolated minor storm intervals are possible.

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
13234 2023.02.20
2023.02.20
18 7 5 N25W76 0820 EKC EKC beta-delta

location: N23W81

area: 0590

13236 2023.02.23
2023.02.23
  1 1 S26W85 0030   HRX location: S23W81
13237 2023.02.23
2023.02.24
      S08W65        

real location: S12W69

SWPC observers were confused by the spots of AR S8315 on February 27 and changed the location to that group

S8306 2023.02.23       N12W56            
S8308 2023.02.24       S21W56          
S8310 2023.02.25       S26W34            
13244 2023.02.25
2023.03.03
2 12 3 S22W19 0030 CRO CRO  
S8313 2023.02.25       N18W43            
13238 2023.02.26
2023.02.27
1 7 3 N09E09 0070 HSX CAO location: N09E12

area: 0090

S8316 2023.02.27       N18W44            
13239 2023.02.27
2023.02.28
1 4 2 N31E28 0100 HSX CAO location: N32E29

area: 0170

S8318 2023.02.27       S29W16            
13241 2023.02.28
2023.03.01
2 3 1 N27E46 0070 HSX HSX

location: N28E43

13240 2023.02.28
2023.03.01
6 5   S16E28 0030 CRO AXX area: 0005

location: S17E32

Not sure what SWPC has observed

S8321 2023.02.28       N41W10            
S8322 2023.03.01       S13W48            
13242 2023.03.01
2023.03.02
8 24 9 N10E53 0230 CAO EAI  
13243 2023.03.01
2023.03.03
4 13 8 N18W37 0010 BXO CRI area: 0040

location: N18W35

S8325 2023.03.01       N17W15            
S8326 2023.03.02       S20E11          
S8327 2023.03.02   12 6 S09E18 0050   DRI  
13245 2023.03.02
2023.03.03
1 4 2 S23E74 0080 HSX HKX area: 0360
S8330 2023.03.03   3   S17E64 0010   AXX    
S8331 2023.03.03   3 1 S32E10 0006   AXX    
S8332 2023.03.03   1 1 N27W02 0006   AXX    
Total spot count: 43 99 42  
Sunspot number: 133 239 162  (total spot count + 10 * number of spotted regions)
Weighted SN: 84 151 93  (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): 146 131 130  

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
2021.08 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 92.3 (+5.8) 10.92
2022.09 135.1 136.5 96.0 (97.0 projected, +4.7) 12.18
2022.10 133.5 132.7 95.4 (100.2 projected, +3.2) 11.16
2022.11 123.4 120.7 77.6 (103.0 projected, +2.8) 9.33
2022.12 147.9 143.4 113.1 (107.8 projected, +4.8) 10.99
2023.01 182.4 176.6 143.6 (113.8 projected, +6.0) 8.73
2023.02 167.2 163.2 110.9 (118.9 projected, +5.1) 14.6
2023.03 165.4 (1)   6.2 (2A) / 96.5 (2B) / 150.4 (2C) (122.0 projected, +3.1) (8.1)
2023.04       (127.4 projected, +5.4)  
2023.05       (133.2 projected, +5.8)  
2023.06       (136.4 projected, +3.2)  
2023.07       (135.9 projected, -0.5)  
2023.08       (136.9 projected, +1.0)  
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.