Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 15, 2023 at 07:50 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 14 due to CME effects after 04h UT. Solar wind speed at SOHO ranged between 304 and 470 km/sec. The high latitude magnetometer at Andenes recorded quiet to major storm levels. A moderately strong solar wind shock was recorded at DSCOVR at 03:48 UT on March 15, probably the arrival of the March 11 CME.

Solar flux density measured at 20h UT on 2.8 GHz was 138.5 - decreasing 35.2 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 137.12). The Potsdam WDC planetary A index was 18 (STAR Ap - based on the mean of three hour interval ap indices: 17.6). Three hour interval K indices: 24333334 (planetary), 24433323 (Boulder), 55234456 (Andenes).

The background x-ray flux was at the class B6 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 12 active regions using 2K resolution (SN: 212) and in 12 active regions using 1K resolution (SN: 163) SDO/HMI images.

Region 13245 [S23W69] decayed slowly and quietly.
Region 13247 [S24W32] developed slowly in the trailing spot section and was mostly quiet. C1 flares: C1.4 @ 08:09, C1.2 @ 22:26 UT
Region 13249 [S11W16] decayed slowly and quietly.
Region 13250 [S18W19] decayed slowly and produced the largest flare of the day. C1 flares: C1.0 @ 23:28 UT
Region 13251 [S13E05] was quiet and stable.
Region 13252 [N12E07] decayed slowly and quietly.
New region 13255 [S05E40] emerged with a few spots.

Spotted regions not observed (or interpreted differently) by SWPC:
S8348 [N25W02] was quiet and stable.
S8355 [N13W22] was quiet and stable. C1 flares: C1.2 @ 07:48 UT
S8360 [N23E20] was quiet and stable.
S8363 [S09E17] was quiet and stable.
New region S8365 [S18E47] emerged with tiny spots.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C3.0 06:05 S18W07 13250 GOES16  
C2.9 11:19   13247 GOES16  

Coronal mass ejections (CMEs)

March 12, 14: No obviously Earth directed CMEs were observed.
March 13: A partial halo CME was observed after a filament eruption in the northeast quadrant near the central meridian just before noon. Components from this CME could reach Earth on March 16. A very impressive backsided full halo CME was observed in LASCO C3 imagery starting at 03:54 UT, the source was likely 5-6 days behind the northeast limb. An associated above 10 MeV proton event began at 07:40 UT on March 13 and peaked at 22 pfu at 04:25 UT on March 15.

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) was in an Earth facing position on March 11-12. A recurrent southern hemisphere coronal hole (CH1135) will likely rotate across the central meridian on March 16-17.

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 to very poor. Propagation on long distance northeast-southwest paths is poor.

Forecast

Quiet to minor storm conditions are likely on March 15-17 due to CME and coronal hole effects.

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
13245 2023.03.02
2023.03.03
2 6 2 S23W70 0090 HSX CSO

area: 0220

location: S23W69

13246 2023.03.04
2023.03.05
      N24W54         location: N23W51
13247 2023.03.05
2023.03.06
1 18 14 S22W38 0020 HAX EAI location: S24W30

area: 0100

SWPC consider this to be 2 regions

13249 2023.03.07
2023.03.07
1 8 1 S11W19 0010 AXX CRO location: S11W16

area: 0020

S8346 2023.03.07       N29W35          
S8348 2023.03.08   3 1 N25W02 0006   AXX  
13251 2023.03.08
2023.03.09
1 7 3 S13E02 0050 HSX CSO area: 0090

location: S13E05

S8350 2023.03.08       N13W55            
13252 2023.03.09
2023.03.10
1 10 3 N12E07 0010 HRX CAO

area: 0030

13250 2023.03.09
2023.03.09
5 21 8 S18W22 0010 BXO DRI location: S18W19

area: 0040

S8354 2023.03.10       S15W59            
S8355 2023.03.10   2 2 N13W22 0007   BXO  
S8356 2023.03.10       S28W09            
13253 2023.03.11
2023.03.12
      S29W29           location: S29W25
S8359 2023.03.11       N15W38            
S8360 2023.03.11   7 3 N23E20 0015   BXO  
S8362 2023.03.13       N08E31          
S8363 2023.03.13   1 1 S09E17 0003   AXX  
13254 2023.03.14 5     S24W28 0050 CAO       AR is inside the bi-polar area of AR 13247, however, SWPC considers it a new region
13255 2023.03.14
2023.03.14
1 7 4 S05E39 0010 BXO DRO   was AR S8364

area: 0030

location: S05E40

S8365 2023.03.13   2 1 S18E47 0003   BXO    
Total spot count: 17 92 43  
Sunspot number: 97 212 163  (total spot count + 10 * number of spotted regions)
Weighted SN: 40 121 72  (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): 107 117 130  

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) 14.48
2023.03 168.4 (1)   59.0 (2A) / 130.7 (2B) / 147.0 (2C) (122.0 projected, +3.1) (11.8)
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.