Solar Terrestrial Activity Report

Activity chart

Last major update issued on February 6, 2023 at 07:10 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 (February 1, 2023) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (February 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 (February 1, 2023) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (February 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 on February 5. Solar wind speed at SOHO ranged between 307 and 367 km/sec. The high latitude magnetometer at Andenes recorded quiet to unsettled levels. A disturbance related to CH1129 began early on February 6.

Solar flux density measured at 20h UT on 2.8 GHz was 144.0 - decreasing 46.9 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 130.95). The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.1). Three hour interval K indices: 02011121 (planetary), 02021221 (Boulder), 12000032 (Andenes).

The background x-ray flux was at the class B9 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 17 active regions using 2K resolution (SN: 297) and in 13 active regions using 1K resolution (SN: 181) SDO/HMI images.

Region 13206 [S24W23] decayed slowly and quietly.
Region 13207 [S14W04] decayed significantly and was mostly quiet. C1 flares: C1.1 @ 00:07 UT
Region 13209 [N18E29] was mostly quiet and stable. A magnetic delta could be forming in a trailing penumbra.
Region 13210 [S15W29] decayed slowly and quietly.
Region 13211 [S17W42] developed slowly and could produce C and maybe minor M class flares. C1 flare: C1.1 @ 19:26 UT
New region 13212 [S17W56] reemerged on February 4 and developed further.

Spotted regions not observed (or interpreted differently) by SWPC:
S8238 [S13E12] was quiet and stable.
S8240 [S10W17] was quiet and stable.
S8241 [S17W19] developed slowly and quietly.
S8242 [N29E28] developed slowly and quietly.
New region S8243 [N26E03] was observed with tiny spots in an old plage area.
New region S8244 [N10E47] emerged with tiny spots.
New region S8245 [N21E71] emerged with a few spots.
New region S8246 [N24E83] rotated partly into view and may be capable of M class flaring. C1 flares: C1.1 @ 05:45, C1.0 @ 11:42 UT
New region S8247 [S27E35] was observed with tiny spots in an old plage area.
New region S8248 [S23E14] emerged with a few spots.
New region S8249 [S34W00] emerged with tiny spots.

A C1.0 flare at 02:50 UT had its origin at the southeast limb.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C6.6 03:26 southeast limb   GOES16  
C6.4 10:51   13211 GOES16  

Coronal mass ejections (CMEs)

February 3-5: No obviously Earth directed CMEs were observed in available LASCO imagery.

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 poorly defined trans equatorial coronal hole (CH1129) will be Earth facing on February 3-4.

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 fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

Quiet to active geomagnetic conditions are likely on February 6-8 due to effects from CH1129.

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
S8214 2023.01.26       S17W51            
13206 2023.01.29
2023.01.29
  10   S21W36 0015   BXO

location: S24W23

13207 2023.01.29
2023.01.30
10 18 11 S14W04 0060 BXO CRO

area: 0035

S8227 2023.01.30       N29W17            
13212 2023.01.30
2023.02.04
3 11 5 S17W56 0020 BXO BXI  
13208 2023.02.01
2023.02.01
      N15W01          

location: N15E02

S8232 2023.02.01       N14W47            
13209 2023.02.01
2023.02.03
6 21 11 N18E26 0060 DSO DRI  
S8234 2023.02.01       S29E13            
13210 2023.02.02
2023.02.03
4 7 3 S17W41 0020 BXO BXO  
13211 2023.02.03
2023.02.04
6 17 10 S17W41 0040 CRO DAI location: S17W42

area: 0100

S8237 2023.02.03       N19W48          
S8238 2023.02.03   11 1 S13E12 0020   AXX  
S8240 2023.02.04   2   S10W17 0003   AXX  
S8241 2023.02.04   4 1 S17W19 0015   CRO  
S8242 2023.02.04   8 2 N29E28 0020   BXO  
S8243 2023.02.05   3   N26E03 0005   AXX    
S8244 2023.02.05   3 1 N10E47 0007   AXX    
S8245 2023.02.05   5 2 N21E71 0020   CRO    
S8246 2023.02.05   1 1 N24E83 0190   HSX    
S8247 2023.02.05   2   S27E35 0003   AXX    
S8248 2023.02.05   2 2 S23E14 0010   CRO    
S8249 2023.02.05   2 1 S34W00 0006   BXO    
Total spot count: 29 127 51  
Sunspot number: 79 297 181  (total spot count + 10 * number of spotted regions)
Weighted SN: 37 152 76  (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): 87 163 145  

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 (solar max) 7.88
2017.09 91.3 92.3 43.6 18.2 (-1.3) 18.22
(cycle 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
2021.07 81.0 83.6 34.3 31.4 (+3.8) 5.51
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 (92.4 projected, +5.9) 10.92
2022.09 135.1 136.5 96.0 (97.4 projected, +5.0) 12.18
2022.10 133.5 132.7 95.4 (100.5 projected, +3.1) 11.16
2022.11 123.4 120.7 77.6 (103.4 projected, +2.9) 9.33
2022.12 147.9 143.4 113.1 (108.2 projected, +4.8) 10.99
2023.01 182.4 176.6 143.6 (114.2 projected, +6.0) 8.7
2023.02 137.2 (1)   13.0 (2A)/ 72.8 (2B) / 167.0 (2C) (119.2 projected, +5.0) (5.6)
2023.03       (122.3 projected, +3.1)  
2023.04       (127.7 projected, +5.4)  
2023.05       (133.5 projected, +5.8)  
2023.06       (136.8 projected, +3.3)  
2023.07       (136.3 projected, -0.5)  
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.