Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 12, 2023 at 14:40 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 unsettled on March 11. Solar wind speed at SOHO ranged between 320 and 386 km/sec. The high latitude magnetometer at Andenes recorded quiet to major storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 157.4 - decreasing 42.3 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 136.93). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.5). Three hour interval K indices: 32101023 (planetary), 12101222 (Boulder), 53111126 (Andenes).

The background x-ray flux was at the class B7 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 16 active regions using 2K resolution (SN: 267) and in 13 active regions using 1K resolution (SN: 176) SDO/HMI images.

Region 13239 [N33W72] was quiet and stable.
Region 13240 [S17W79] was quiet and stable.
Region 13241 [N29W59] was quiet and stable.
Region 13242 [N11W61] decayed slowly and quietly.
Region 13245 [S22W29] decayed slowly and produced a few C flares. C1 flares: C1.4 @ 05:35, C1.3 @ 06:10, C1.2 @ 10:16, C1.2 @ 10:38, C1.6 @ 15:01 UT
Region 13246 [N24W12] decayed slowly and quietly.
Region 13247 [S24E03] was quiet and stable.
Region 13249 [S12E23] developed slowly and quietly.
Region 13250 [S19E19] was mostly quiet and stable.
Region 13251 [S13E44] was quiet and stable.
Region 13252 [N13E46] was quiet and stable.

Spotted regions not observed (or interpreted differently) by SWPC:
S8348 [N23E33] decayed slowly after noon.
New region S8357 [S30E14] emerged with several spots.
New region S8358 [S03W49] emerged with tiny spots.
New region S8359 [N15E01] emerged with tiny spots.
New region S8360 [N19E68] rotated into view with a tiny spot.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C4.9 01:03 S25W17 13245 GOES16  
C2.0 14:39   13245 GOES16  

Coronal mass ejections (CMEs)

March 9, 11: No obviously Earth directed CMEs were observed.
March 10: A partial halo CME was observed after a large filament eruption in the southwestern and northwestern quadrants. The CME could reach Earth after noon on March 13 and cause unsettled to minor storm conditions.

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 (CH1134) will be in an Earth facing position on March 11-12.

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 is likely on March 12-13. The March 10 CME could reach Earth on March or 14 and cause unsettled to minor storm conditions. Unsettled and active intervals are possible on March 14-15 due to effects from CH1134.

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
13239 2023.02.27
2023.02.28
1 1 1 N32W70 0070 HSX HSX location: N33W72

area: 0100

13241 2023.02.28
2023.03.01
1 2 1 N28W61 0030 HSX HRX

location: N29W59

area: 0030

13240 2023.02.28
2023.03.01
  1   S17W79 0002   AXX

SWPC on March 6 moved the location to near AR S8327

13242 2023.03.01
2023.03.02
1 8 1 N10W57 0100 HSX CSO

location: N11W61

area: 0200

13245 2023.03.02
2023.03.03
7 22 9 S23W31 0220 CSO DHO

area: 0290

location: S22W29

S8330 2023.03.03       S17W40            
13246 2023.03.04
2023.03.05
2 3 3 N24W13 0030 HSX HAX location: N24W12

area: 0050

S8335 2023.03.04       N22W54            
S8336 2023.03.04       S08W46            
13247 2023.03.05
2023.03.06
4 15 4 S23E03 0070 CSO CSO location: S24E03

area: 0080

S8343 2023.03.06       S12W30            
13249 2023.03.07
2023.03.07
1 10 4 S11E21 0060 HSX CAO location: S12E23

area: 0070

S8346 2023.03.07       N33E10            
S8348 2023.03.08   6 2 N23E33 0010   BXO  
13251 2023.03.08
2023.03.09
1 6 1 S13E42 0050 HSX CAO area: 0100

location: S13E44

S8350 2023.03.08       N13W16            
13252 2023.03.09
2023.03.10
1 1 1 N13E47 0020 HSX HSX location: N12E46

area: 0040

13250 2023.03.09
2023.03.09
7 18 14 S20E19 0070 CAO DRI location: S19E19

area: 0110

S8353 2023.03.09       S29W47            
S8354 2023.03.10       S15W20          
S8355 2023.03.10       N12E12          
S8356 2023.03.10       S28E30          
S8357 2023.03.11   9 4 S30E14 0025   CRO    
S8358 2023.03.11   2   S03W49 0002   BXO    
S8359 2023.03.11   2   N15E01 0002   AXX    
S8360 2023.03.11   1 1 N19E68 0002   AXX    
Total spot count: 26 107 46  
Sunspot number: 126 267 176  (total spot count + 10 * number of spotted regions)
Weighted SN: 76 161 100  (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): 139 147 141  

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
2023.03 175.0 (1)   48.7 (2A) / 137.4 (2B) / 156.5(2C) (122.0 projected, +3.1) (12.6)
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.