Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 8, 2023 at 08:55 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 7 under the influence of a high speed stream from CH1133. Solar wind speed at SOHO ranged between 451 and 731 km/sec, dropping quickly after 16h UT signaling the end of the disturbance. The high latitude magnetometer at Andenes recorded quiet to active levels.

Solar flux density measured at 20h UT on 2.8 GHz was 180.3 - decreasing 17.3 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 136.38). The Potsdam WDC planetary A index was 9 (STAR Ap - based on the mean of three hour interval ap indices: 9.4). Three hour interval K indices: 33332111 (planetary), 23333211 (Boulder), 44333222 (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 15 active regions using 2K resolution (SN: 306) and in 12 active regions using 1K resolution (SN: 194) SDO/HMI images.

Region 13238 [N08W42] decayed slowly and quietly.
Region 13239 [N33W20] decayed slowly and quietly.
Region 13240 [S17W21] decayed slowly and quietly.
Region 13241 [N28W07] gained some tiny spots and was quiet.
Region 13242 [N09W03] decayed losing area and spots. The magnetic delta in the intermediate spot section decayed as well. An M class flare is possible. C1 flares: C1.7 @ 01:07 UT
Region 13243 [N19W85] rotated mostly out of view. C1 flares: C1.7 @ 06:41, C1.6 @ 12:50 UT
Region 13244 [S22W72] decayed slowly and quietly.
Region 13245 [S22E23] displayed signs of decay and lost the magnetic delta. An M class flare is possible. C1 flares: C1.8 @ 10:37, C1.3 @ 14:46 UT
Region 13246 [N23E41] developed slightly and was quiet.
Region 13247 [S23E56] was mostly quiet and stable.
Region 13248 [N15W60] decayed slowly and quietly.
New region 13249 [S12E77] rotated into view with a mature spot.

Spotted regions not observed (or interpreted differently) by SWPC:
S8327 [S09W38] decayed slowly and quietly.
S8341 [S04W08] decayed slowly and quietly.
New region S8346 [N26E58] was observed with tiny spots in an old plage area.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C4.0 02:39 S26E40 13245 GOES16 LDE
C4.7 04:05   13243 GOES16  
C2.5 04:19   13247 GOES16  
C3.0 08:20   13243 GOES16  
C2.6 17:49   13245 GOES16 LDE
C2.1 20:52 northwest limb   GOES16  

Coronal mass ejections (CMEs)

March 5, 7: No obviously Earth directed CMEs were observed.
March 6: A faint full halo CME was observed after the major M5.8 flare in AR 13243 early in the day. While the main ejecta will not reach Earth, there is a chance of weak effects reaching Earth sometime between noon on March 8 and noon on March 9.

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]

No obvious coronal hole are currently in or near Earth facing positions.

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 8-10 with a chance of active intervals should a component of the February 6 CME reach Earth.

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
13244 2023.02.25
2023.03.03
7 6 3 S22W74 0030 CRO CRO

location: S22W72

13238 2023.02.26
2023.02.27
1 3 1 N08W44 0030 HSX CAO location: N08W42

area: 0050

13239 2023.02.27
2023.02.28
1 2 1 N33W25 0100 HSX CSO location: N33W20

area: 0140

13241 2023.02.28
2023.03.01
1 14 6 N28W08 0040 HSX CSO

location: N28W07

area: 0060

13240 2023.02.28
2023.03.01
4 6 2 S10W35 0010 CRO BXO area: 0010

location: S17W21

SWPC on March 6 moved the location to near AR S8327

13242 2023.03.01
2023.03.02
27 49 23 N10W02 0300 ESC ESI beta-delta

area: 0260

location: N09W03

13243 2023.03.01
2023.03.03
1 1   N18W89 0080 DAO AXX

location: N19W85

S8326 2023.03.02       S20W41            
S8327 2023.03.02   5 2 S09W38 0010   CRO  
13245 2023.03.02
2023.03.03
13 31 17 S22E22 0300 DKI DKC

area: 0460

location: S22E23

S8330 2023.03.03       S17E12            
S8331 2023.03.03       S30W24          
S8333 2023.03.04       N28W46            
13246 2023.03.04
2023.03.05
3 10 6 N24E42 0060 CAO DAO location: N23E41
S8335 2023.03.04       N22W02            
S8336 2023.03.04       S08E06            
13247 2023.03.05
2023.03.06
3 10 5 S23E54 0090 CSO CSO location: S23E56
13248 2023.03.05
2023.03.06
9 14 7 N19W60 0050 CRO CRI location: N15W60
S8340 2023.03.05       N28W31            
S8341 2023.03.05   2   S04W08 0004   AXX  
S8343 2023.03.06       S12E22          
13249 2023.03.07
2023.03.07
1 1 1 S12E75 0120 HSX HSX   location: S12E77

was AR S8344

S8346 2023.03.07   2   N26E58 0002   AXX    
Total spot count: 71 156 74  
Sunspot number: 191 306 194  (total spot count + 10 * number of spotted regions)
Weighted SN: 127 210 128  (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): 210 168 155  

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
2023.03 176.6 (1)   30.6 (2A) / 135.6 (2B) / 159.1 (2C) (122.0 projected, +3.1) (14.6)
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.