Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 10, 2023 at 09:40 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 active on March 9. Solar wind speed at SOHO ranged between 369 and 468 km/sec. The high latitude magnetometer at Andenes recorded unsettled to minor storm levels. The earthbound ejecta from the March 6 CME appears to have become embedded in the solar wind and was the most likely cause of a disturbance starting early on March 9.

Solar flux density measured at 20h UT on 2.8 GHz was 178.8 - decreasing 29.0 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 136.73). The Potsdam WDC planetary A index was 15 (STAR Ap - based on the mean of three hour interval ap indices: 15.1). Three hour interval K indices: 24443322 (planetary), 23533232 (Boulder), 35444444 (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 16 active regions using 2K resolution (SN: 304) and in 15 active regions using 1K resolution (SN: 222) SDO/HMI images.

Region 13238 [N09W70] was quiet and stable.
Region 13239 [N33W46] was quiet and stable.
Region 13240 [S19W38] was quiet and stable.
Region 13241 [N28W32] was quiet and stable.
Region 13242 [N10W32] decayed quickly and produced a few C flares. C1 flares: C1.4 @ 06:31 UT
Region 13245 [S22W03] still has polarity intermixing in the penumbrae to the east of the main penumbra. A major flare is possible. C1 flares: C1.5 @ 11:02, C1.9 @ 12:46 UT
Region 13246 [N24E15] was quiet and stable.
Region 13247 [S23E28] was quiet and stable. AR 13250 was split off.
Region 13248 [N15W81] developed as it rotated to the northwest limb. An M class flare is possible as the region transits the limb. C1 flares: C1.8 @ 00:06, C1.4 @ 06:56 UT
Region 13249 [S12E49] was quiet and stable.
New region 13250 [S19E46] was split off from AR 13247 as new flux emerged. Many small spots formed. C1 flares: C1.5 @ 08:07, C1.6 @ 19:29 UT
New region 13251 [S13E69] rotated into view on March 8 and was numbered the next day by SWPC.

Spotted regions not observed (or interpreted differently) by SWPC:
S8346 [N24E15] reemerged with tiny spots.
S8348 [N22E60] was mostly quiet and stable
New region S8351 [N12E73] rotated into view with a mature spot.
New region S8353 [S29W21] emerged with a tiny spot.

Two coronal shocks were recorded (over all limbs and the north and south pole) at 13:18 and 20:48 UT, in both cases immediately followed by a CME. The first event, taking into account the distribution of the ejecta, was likely 5-6 days behind the west limb and was observed as a full halo CME. The second CME was smaller with most of the ejecta seen off the south pole and was probably also backsided. However, the C6 flare in AR 13245 at 20:24 UT may be within the time frame expected from the CME source. The available data will be reevaluated today.

AR 13244 behind the southwest limb was the source of a C1.8 flare at 10:11 UT.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C4.2 00:54 N11W10 13242 GOES16  
C3.9 01:19   13248 GOES16  
C3.1 09:04   13245 GOES16 LDE
C3.0/1F 13:53 N12W11 13242 GOES16  
C3.5 14:14   13242 GOES16  
C2.1 16:37   13245 GOES16  
C2.4 18:16   13250 GOES16  
C2.6 18:30   13245 GOES16  
C3.1 20:11   13245 GOES16  
C6.2 20:24   13245 GOES16  
C2.9 21:09   13250 GOES16  
C3.4 23:31   S8348 GOES16  

Coronal mass ejections (CMEs)

March 7-9: 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 northern hemisphere coronal hole (CH1134] will likely rotate into 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 active conditions are likely on March 10 due to CME effects. Quiet to unsettled is likely on March 11-12.

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
13238 2023.02.26
2023.02.27
1 1 1 N09W72 0010 AXX AXX location: N09W70

area: 0003

13239 2023.02.27
2023.02.28
1 1 1 N32W41 0070 HSX HSX location: N33W46

area: 0110

13241 2023.02.28
2023.03.01
1 7 2 N28W36 0020 HSX CSO

location: N28W32

area: 0040

13240 2023.02.28
2023.03.01
  3 2 S09W63 0010   BXO

location: S19W38

SWPC on March 6 moved the location to near AR S8327

13242 2023.03.01
2023.03.02
13 34 13 N09W29 0170 ESI EAO

location: N10W32

13245 2023.03.02
2023.03.03
11 43 21 S24W07 0250 DHO DHI

beta-gamma

area: 0430

location: S22W03

S8330 2023.03.03       S17W14            
S8331 2023.03.03       S30W50            
13246 2023.03.04
2023.03.05
1 5 4 N25E14 0040 HAX DSO location: N24E15

area: 0080

S8335 2023.03.04       N22W28            
S8336 2023.03.04       S08W20            
13247 2023.03.05
2023.03.06
5 18 9 S24E28 0070 CSO CSO location: S23E28

area: 0110

13248 2023.03.05
2023.03.06
6 1 1 N15W85 0020 CRO DRO location: N15W81

area: 0200

S8340 2023.03.05       N28W57            
S8341 2023.03.05       S04W35          
S8343 2023.03.06       S12W04            
13249 2023.03.07
2023.03.07
1 3 2 S11E47 0030 HAX HSX location: S12E49

area: 0100

S8346 2023.03.07   3   N33E36 0003   AXX    
S8348 2023.03.08   4 2 N22E60 0010   BXO  
13251 2023.03.08
2023.03.09
1 1 1 S13E69 0050 HSX HSX area: 0110
S8350 2023.03.08       N13E10          
S8351 2023.03.09   1 1 N12E73     HSX    
13250 2023.03.09
2023.03.09
4 18 11 S20E45 0010 BXO DRI   split off from AR 13247

location: S19E46

area: 0070

was AR S8352

S8353 2023.03.09   1 1 S29W21 0003   AXX    
Total spot count: 45 144 72  
Sunspot number: 155 304 222  (total spot count + 10 * number of spotted regions)
Weighted SN: 93 200 128  (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): 171 167 178  

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
2023.03 177.4 (1)   40.3 (2A) / 138.9 (2B) / 159.9 (2C) (122.0 projected, +3.1) (13.7)
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.