Solar Terrestrial Activity Report

Activity chart

Last major update issued on February 10, 2025 at 06:20 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 7, 2025)
Solar cycle Solar cycles 23-25 (February 1, 2025) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (February 1, 2025) Noon SDO sunspot count 1K image / 4K (*)
  Solar cycles 1-24 (August 1, 2020) POES auroral activity level [October 2009 - December 2012]
  Comparison of cycles 21-25 (February 1, 2025) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (February 1, 2025) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (January 11, 2025) 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
Calculating the Strength of Solar Cycle 25 Using 365-day Smoothing

Recent activity

The geomagnetic field was at quiet to minor storm levels on February 9 due to effects from CH1269. Solar wind speed at SOHO ranged between 325 and 676 km/sec, averaging 434 km/sec (+96 km/sec compared to the previous day. The high latitude magnetometer at Andenes recorded quiet to minor storm levels. The above 10 MeV proton flux was at background levels all day.

Solar flux density measured at 20h UT on 2.8 GHz was 163.0 - increasing 3.3 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 193.23. In comparison SC24 peaked on June 28, 2014 at 145.50 while SC23 peaked on February 23, 2002 at 198.15. Current SC25 peak: 193.35 on August 7, 2024 (subtracting a base solar flux level of 65, this is +59.44% compared to the SC24 peak and -3.61% compared to the SC23 peak). The Potsdam WDC planetary A index was 17 (STAR Ap - based on the mean of three hour interval ap indices: 17.4). Three hour interval K indices: 12123454 (planetary), 12223444 (Boulder), 12012455 (Andenes).

The background x-ray flux is at the class C2 level (GOES 18).

At the time of counting spots (see image time), spots were observed in 13 active regions using 2K resolution (SN: 226) and in 11 active regions using 1K resolution (SN: 151) SDO/HMI images.

AR 13978 [N10W82] decayed slowly and quietly.
AR 13983 [N06W07] saw new flux and spots emerge immediately to the north of the leader spot. While this is probably a separate spot group, the latitudinal separation is too small to maintain a split.
AR 13985 [N22W53] decayed slowly and quietly.
AR 13986 [N06E17] was quiet and stable.
AR 13987 [S09E26] was quiet and stable.
AR 13988 [S18W36] was quiet and stable.
New AR 13989 [N18E65] rotated into view on February 8 and was numbered the next day by SWPC.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S10759 [N07W71] decayed slowly and produced several C flares. C1 flares: C1.7 @ 05:11, C1.7 @ 10:19 UT
S10762 [N12W75] decayed further and was mostly quiet. C1 flares: C1.6 @ 05:47 UT
S10781 [S14W19] was quiet and stable.
S10782 [S14E31] was quiet and stable.
New region S10783 [S10E80] rotated into view and has M class flare potential.
New region S10784 [S09W06] was observed with tiny spots in an old plage area.

C2+ flares

Magnitude Peak time (UT) Location Source Recorded by Comment
C4.5 01:01 SE limb S10783 GOES16 simultaneous flare in AR 13976
C2.7 01:35   S10762 GOES16  
C2.1 02:15   S10759 GOES16  
C4.4 02:49   S10759 GOES16  
C3.9 03:21   S10759 GOES16  
C3.1 03:40   S10759 GOES16  
C2.1 04:20   S10759 GOES16  
C2.8 07:12   13978 GOES16  
C2.0 08:54   S10783 GOES16  
C4.1 14:13   S10759 GOES16  
C2.1 14:42   S10759 GOES16  
C2.1 19:32   13978 GOES16  
C2.5 19:40   S10782 GOES16  
C3.9 20:25 behind NW limb 13977 GOES16  
C3.1 20:59   S10759 GOES16  
C2.4 21:15   S10759 GOES16  
C3.0 23:53   S10759 GOES16  

Coronal mass ejections (CMEs)

February 7-9: No obviously Earth directed CMEs.

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 recurrent negative polarity trans equatorial coronal hole (CH1269) rotated across the central meridian on February 6-8. A recurrent negative polarity southern hemisphere coronal hole (CH1270) will rotate into an Earth facing position on February 9-12.

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 to fair.

Forecast

The geomagnetic field is expected to be at quiet to minor levels on February 10 and quiet to active levels on February 11-12 due to effects from CH1269. A high speed stream from CH1270 could cause quiet to active levels on February 13-16.

Coronal holes (1) Coronal mass ejections (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
STAR SWPC STAR Current Previous
2K 1K
13976 2025.01.27
2025.01.27
1     N11W96 0080 HSX       rotared out of view
13977 2025.01.27
2025.01.27
1     N18W96 0010 AXX      

spotless since 2025.02.08, rotated out of view 2025.02.09

13978 2025.01.28
2025.01.28
1 1 1 N11W80 0030 HRX HAX    

location: N10W82

13980 2025.01.29
2025.01.30
      S12W79           was AR S10752

location: S12W72

S10753 2025.01.29       N06W62           reinstated on 2025.02.02 due to SWPC using AR 13981 for two different spot groups
13981 2025.01.30 8     N07W69 0200 EAC       see AR S10753/S10759

This was initially AR S10753. SWPC moved the location of AR 13981 to that of AR S10759, a separate spot group which emerged on January 31.

13982 2025.01.30       N21W79           was AR S10754

location: N23W76

13984 2025.01.30
2025.02.04
8     N10W85 0060 DAO       was AR S10755

spotless, there are no spots where SWPC is reporting spots

location: N15W81

SWPC location on 2025.02.08 was N15W66

S10759 2025.01.31   24 10 N07W71 0830   EKI     beta-gamma-delta

This is currently AR 13981 to SWPC

S10762 2025.02.01   4 1 N12W75 0015   CRO      
13985 2025.02.01
2025.02.04
1 2 1 N23W52 0005 AXX AXX     was AR S10763

location: N22W53

area: 0010

13988 2025.02.02
2025.02.07
3 14 5 S18W37 0010 CRO DRO     was AR S10766

area: 0040

S10767 2025.02.02       S20W53            
S10768 2025.02.03       N20W51            
13983 2025.02.03
2025.02.04
3 17 10 N06W07 0040 CSO CAI     was AR S10769

area: 0100

S10770 2025.02.03       N25W47            
13986 2025.02.04
2025.02.05
2 8 3 N06E15 0140 HSX CAO     was AR S10772

area: 0200

location: N06E17

13987 2025.02.05
2025.02.06
3 7 3 S09E24 0010 HRX CRO     was AR S10774

area: 0020

location: S09E26

S10775 2025.02.05       S43W18            
S10776 2025.02.06       S27W45            
S10779 2025.02.07       N23W18            
13989 2025.02.08
2025.02.09
1 1 1 N18E64 0120 HSX HHX     was AR S10780

area 0280

S10781 2025.02.08   8 4 S14W19 0020   BXO      
S10782 2025.02.08   1   S14E31 0001   AXX      
S10783 2025.02.09   6 3 S10E80 0450   CKO      
S10784 2025.02.09   3   S09W06 0005   AXX      
Total spot count: 32 96 42  
Sunspot number: 142 226 152  (total spot count + 10 * number of spotted regions)
Weighted SN: 71 150 96  (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): 156 124 122  

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
2023.06 161.7 166.8 160.5 125.3 (+1.1) 8.95
2023.07  176.4 182.2 160.0 124.6 (-0.7) 8.15
2023.08  153.7 157.6 114.8 124.3 (-0.3) 7.19
2023.09  154.4 156.0 134.2 124.0 (-0.3) 14.26
2023.10  142.8 141.9 99.4 124.8 (+0.8) 8.16
2023.11 153.5 150.2 105.4 127.9 (+3.1) 12.20
2023.12 151.1 146.4 114.2 129.5 (+1.6) 9.60
2024.01 164.6 159.3 126.0 131.2 (+1.7) 5.46
2024.02 172.5 168.3 123.0 136.9 (+5.7) 5.31
2024.03 154.4 152.9 103.7 141.4 (+4.5) 11.03
2024.04 161.3 162.6 137.0 144.5 (+3.1) 9.69
2024.05 187.7 191.9 172.1 149.1 (+4.6) 23.56
(SC25 peak)
2024.06 184.3 190.2 164.1 152.7 (+3.6) 10.24
2024.07 196.6 203.0 196.8 154.9 (+2.3) 7.13
2024.08  246.1
(cycle peak)
252.2 216.0  (SC25 peak) (156.2 projected, +1.3) 15.96
2024.09 195.7 197.8 141.1 (158.3 projected, +2.1) 15.36
2024.10 221.0 219.6 166.3 (159.1 projected, +0.8) 18.99
2024.11 199.6 195.3 152.5 (156.5 projected, -2.6) 9.33
2024.12 197.3 191.2 154.5 (152.1 projected, -4.4) 8.42
2025.01 190.3 184.2  137.0 (145.8 projected, -6.3) 13.17
2025.02  191.6 (1)   52.3 (2A) / 162.8 (2B) / 169.2 (2C) (137.2 projected, -8.6) (10.2)
2025.03       (130.8 projected, -6.4)  
2025.04       (126.2 projected, -4.6)  
2025.05       (120.9 projected, -5.3)  
2025.06       (115.6 projected, -5.3)  
2025.07       (110.9 projected, -4.7)  

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 27 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: WDC-SILSO, Royal Observatory Of Belgium, Brussels

Solar cycles 24-25

Smoothed SF and sunspot numbers

Update on the progress of solar cycle 25 as of December 30, 2024

Sunspot activity increased again during the second half of December 2024, and this will be the eighth consecutive month with average solar flux above 180. The average solar flux at 1 AU since May 1, 2024 is 205. There is an increasing chance solar cycle 25 could have a higher 1 year solar flux average than solar cycle 23. The above plot displays a projected peak for the ISN 365d smoothed sunspot number on October 12, 2024. All the other smoothed sunspot numbers as well as the smoothed 365d solar flux have projected peaks October 12-15. A sudden decrease in activity during the first months of 2025 could move the SC25 max to sometime between July and October 2024.

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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.