Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 2, 2023 at 04:30 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 (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 unsettled on March 1. Solar wind speed at SOHO ranged between 531 and 755 km/sec. The high latitude magnetometer at Andenes recorded quiet to minor storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 162.0 - increasing 27.1 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 135.34). The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.0). Three hour interval K indices: 31131122 (planetary), ******** (Boulder), 21021112 (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: 217) and in 9 active regions using 1K resolution (SN: 125) SDO/HMI images.

Region 13230 [S22W69] decayed slowly and was quietly.
Region 13234 [N23W53] decayed in the trailing spot section. A major flare is possible as there are still multiple magnetic deltas. C1 flares: C1.8 @ 12:13, C1.8 @ 15:31, C1.8 @ 20:25 UT
Region 13236 [S26W58] decayed slowly and was mostly quiet.
Region 13238 [N09E38] was quiet and stable.
Region 13239 [N32E56] was quiet and stable.
New region 13240 [S14E54] emerged on February 28 and was numbered the next day by SWPC. The region was unstable early in the day.
New region 13241 [N28E70] rotated into view on February 28 and received its NOAA number the following day.

Spotted regions not observed (or interpreted differently) by SWPC:
S8308 [S28W27] reemerged with tiny spots.
S8311 [S20E05] was quiet and stable.
S8315 [S08W39] reemerged with a tiny spot.
New region S8322 [S13W22] emerged before noon, then decayed slowly.
New region S8323 [N11E81] rotated into view with mature spots.
New region S8324 [N18W09] emerged with a tiny spot.
New region S8325 [N17E11] emerged with a tiny spot.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.1 00:32   13240 GOES16  
M1.0/1N 01:07   13234 GOES16 simultaneous, smaller flare in AR 13240
C5.4 01:40   13234 GOES16  
C9.3 01:47 S15E69 13240 GOES16  
C5.1 03:20   13234 GOES16  
C3.1 04:04 N24W33 13234 GOES16  
C6.3 04:19 S15E69 13240 GOES16  
C2.4 06:16   13234 GOES16  
C3.0 06:30   13234 GOES16  
C4.3 06:49   13234 GOES16  
C2.3 07:35   13234 GOES16  
C3.0 09:10 N22W39 13234 GOES16  
C2.3 11:42   13234 GOES16  
C4.2 13:58   13236 GOES16  
C2.0 19:36   13236 GOES16  
C2.7 23:22   13234 GOES16  

Coronal mass ejections (CMEs)

February 27 - March 1: 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) will rotate across the central meridian on March 1-2.

Propagation

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

Forecast

Quiet to unsettled conditions are likely on March 2-3. Effects from CH1133 could cause unsettled to minor storm conditions on March 4-5.

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
13230 2023.02.17
2023.02.18
2 3   S23W72 0000 AXX BXO location: S22W69

area: 0006

13234 2023.02.20
2023.02.20
20 31 17 N25W49 0850 FKC EKC beta-gamma-delta

location: N23W53

area: 0740

S8301 2023.02.21       S12W54            
13235 2023.02.22
2023.02.23
      N19W73            
13236 2023.02.23
2023.02.23
5 15 7 S27W58 0030 CSO CRO location: S26W58
13237 2023.02.23
2023.02.24
      S08W38          

real location: S13W43

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

S8306 2023.02.23       N12W30            
S8308 2023.02.24   4   S22W32 0007   BXO    
S8309 2023.02.25       N13W28            
S8310 2023.02.25       S26W08          
S8311 2023.02.25   6 1 S20E05 0015   BXO  
S8313 2023.02.25       N18W17            
13238 2023.02.26
2023.02.27
1 3 1 N09E36 0070 HSX HSX location: N09E38

area: 0140

S8315 2023.02.26   1   S08W38 0001   AXX    
S8316 2023.02.27       N18W18          
13239 2023.02.27
2023.02.28
1 2 1 N30E55 0100 HSX HSX location: N32E56

area: 0220

S8318 2023.02.27       S29E10            
13241 2023.02.28
2023.03.01
3 2 2 N27E73 0050 HSX HAX area: 0080

location: N28E70

13240 2023.02.28
2023.03.01
3 4 3 S16E55 0010   BXO area: 0015

location: S14E54

S8321 2023.02.28       N41E16          
S8322 2023.03.01   2   S13W22 0002   BXO    
S8323 2023.03.01   2 2 N11E81 0240   HAX    
S8324 2023.03.01   1 1 N18W09 0003   AXX    
S8325 2023.03.01   1   N17E11 0002   AXX    
Total spot count: 35 77 35  
Sunspot number: 105 217 125  (total spot count + 10 * number of spotted regions)
Weighted SN: 65 110 68  (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): 116 119 100  

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
2023.03 162.0 (1)   3.4 (2A) / 105 (2B) / 149.6 (2C) (122.0 projected, +3.1) (8.0)
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.