Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 8, 2024 at 06:40 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 (January 1, 2024)
Solar cycle Solar cycles 23-25 (January 1, 2024) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24-25 progress (January 1, 2024) 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 (January 1, 2024) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12-14, 16, 24-25 (January 1, 2024) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (January  3, 2024) 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 (new)

Recent activity

The geomagnetic field was inactive on January 7. Solar wind speed at SOHO ranged between 289 and 359 km/sec. The high latitude magnetometer at Andenes recorded quiet levels.

Solar flux density measured at 20h UT on 2.8 GHz was 167.1 - increasing 41.2 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 158.33. In comparison SC24 peaked on June 28, 2014 at 145.50. Current SC25 peak: 158.71 on June 27, 2023). The Potsdam WDC planetary A index was 1 (STAR Ap - based on the mean of three hour interval ap indices: 1.3). Three hour interval K indices: 00000000 (planetary), 00011211 (Boulder), 20000000 (Andenes).

The background x-ray flux is 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: 342) and in 13 active regions using 1K resolution (SN: 232) SDO/HMI images.

Region 13534 [S14W85] decayed slowly and was mostly quiet.
Region 13536 [N05W19] developed early in the day gaining spots and area. Some of these spots disappeared late in the day. A minor M class flare is possible. C1 flares: C1.2 @ 00:56, C1.8 @ 03:39, C1.6 @ 05:48 UT
Region 13537 [N17W18] decayed slowly and quietly.
Region 13538 [N20W41] decayed early in the day, then developed slowly after noon. C1 flares: C1.4 @ 11:35, C1.2 @ 12:22, C1.7 @ 15:20 UT
Region 13539 [N10W01] developed slowly and was mostly quiet.
Region 13540 [S18E43] lost area in the leading spot section and still has minor M class flare potential. C1 flares: C1.6 @ 04:18, C1.7 @ 19:53, C1.7 @ 21:42 UT
Region 13541 [S22E41] decayed slowly and quietly.
New region 13543 [S07W19] emerged on January 6 and developed further the next day and was numbered by SWPC. C flares are likely.
New region 13544 [N18E57] rotated into view on January 5 and was numbered 2 days later by SWPC as the region decayed.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9279 [N08W13] decayed slowly. A spot previously counted with AR 13536 was included in this region.
S9293 [N27E21] was quiet and stable.
S9297 [S09E30] reemerged with tiny spots.
S9303 [S11E59] was quiet and stable.
New region S9305 [S13W21] emerged with tiny spots.
New region S9306 [S15E05] emerged with a tiny spot.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.2 02:14   13539 GOES16  
C2.3 02:31   13538 GOES16  
C2.2 02:43   13536 GOES16  
C2.7 05:29 N03W07 13536 GOES16  
C2.4 06:05 N03W05 13536 GOES16  
C2.2 06:17   13536 GOES16  
C3.1 06:36 N03W08 13536 GOES16  
C5.6 07:48   13536 GOES16  
C6.3/1N 07:56 N04W10 13536 GOES16  
C3.2/1F 08:33 N05W10 13536 GOES16  
C2.2 10:05   13539 GOES16 incorrectly attributed to AR 13536 by SWPC
C3.0 10:16   13539 GOES16 incorrectly attributed to AR 13536 by SWPC
C2.9 10:51   13539 GOES16 incorrectly attributed to AR 13536 by SWPC
C2.0 11:09   13538 GOES16  
C2.0 13:20   13538 GOES16  
C4.2 13:42   13539 GOES16 incorrectly attributed to AR 13536 by SWPC
C2.5 14:10   13540 GOES16  
C2.1 16:18   13536 GOES16  
C3.3 17:26   S9279 GOES16  
C3.8 17:44   13538 GOES16  
C3.4 17:52   13538 GOES16  
C3.3 21:03 N21W41 13538 GOES16  
C8.7 22:25 southwest limb 13534 GOES16  
C4.7 22:47   13536 GOES16  
C3.7 23:27 behind southeast limb   GOES16  

Coronal mass ejections (CMEs)

January 5-7: No obviously Earth directed CME 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 positive polarity southern hemisphere coronal hole (CH1196) was Earth facing on January 4-6. CH1196 may be too far to the south to cause a geomagnetic disturbance.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle and high latitudes is good. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet on January 8-10, however, weak effects from CH1196 are possible on January 8-9.

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
Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
13534 2023.12.26
2023.12.27
2 1 1 S12W86 0080 HSX HRX

location: S14W85

area: 0030

13536 2023.12.31
2023.12.31
18 32 17 N05W20 0100 EAI DAI beta-gamma

location: N05W19

area: 0130

S9279 2023.12.31   9 4 N08W12 0070   CSO  
13538 2023.12.31
2024.01.03
10 28 14 N25W42 0030 CRI ERI beta-gamma

location: N20W41

area: 0090

S9284 2024.01.01       S01W57            
13537 2024.01.01
2024.01.02
2 8 3 N18W23 0060 HAX CSO area: 0070

location: N17W18

S9289 2024.01.02       S13W55            
S9291 2024.01.03       N12E23            
S9292 2024.01.03       N21W34            
S9293 2024.01.04   2 1 N27E21 0004   BXO  
13541 2024.01.04
2024.01.05
3 11 6 S20E43 0060 CAO DRO location: S22E41
13540 2024.01.04
2024.01.05
17 34 22 S17E47 0310 EKI DAI area: 0350

location: S18E43

S9296 2024.01.04       S13W13            
S9297 2024.01.04   3 1 S09E30 0007   BXO    
S9298 2024.01.04       S15W36            
13539 2024.01.05 7 24 11 N11W01 0030 DRI DRI beta-gamma

location: N10W01

area: 0070

13542 2024.01.05 3     N16W15 0050 CAO       this is the eastern part of AR 13537
S9299 2024.01.05       N21W03          
13544 2024.01.05
2024.01.07
1 1 1 N19E60 0030 HAX HSX location: N18E57
S9301 2024.01.05       N35W03            
13543 2024.01.06
2024.01.07
8 33 20 S05W21 0050 DAI DAI area: 0170

location: S07W19

S9303 2024.01.06   3   S11E59 0003   BXO  
S9304 2024.01.06       N19E06          
S9305 2024.01.07   2 1 S13W21 0005   BXO    
S9306 2024.01.07   1   S15E05 0002   AXX    
Total spot count: 71 192 102  
Sunspot number: 171 342 232  (total spot count + 10 * number of spotted regions)
Weighted SN: 122 233 143  (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): 188 188 186  

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
2022.05 133.8 136.8 96.5 77.4 (+4.4) 7.48
2022.06 116.1 119.8 70.3 81.1 (+3.7) 8.20
2022.07 125.4 129.5 91.4 86.7 (+5.6) 9.51
2022.08 114.2 117.1 74.6 92.6 (+5.9) 10.92
2022.09 135.1 136.5 96.0 96.5 (+3.9) 12.18
2022.10 133.5 132.7 95.5 98.9 (+2.4) 11.16
2022.11 123.4 120.7 80.5 101.2 (+2.3) 9.33
2022.12 147.9 143.4 112.8 106.7 (+5.5) 10.99
2023.01 182.4 176.6 144.4 113.3 (+6.6) 8.73
2023.02 167.2 163.2 111.3 117.8 (+3.5) 14.48
(current
SC25 peak)
2023.03 157.2 155.6 123.3 121.0 (+3.2) 14.42
2023.04 145.4 146.4 97.6 122.7 (+1.7) 13.40
2023.05 155.6 159.2 137.4 123.9 (+1.2) 10.67
2023.06 161.7 166.8 160.5 125.0 (+1.1)
(SC25 solar max candidate)
8.95
2023.07  176.4 182.2 159.1 (124.6 projected, -0.4) 8.15
2023.08  153.7 157.6 114.8 (124.1 projected, -0.5) 7.19
2023.09  154.4 156.0 133.6 (123.8 projected, -0.3) 14.26
2023.10  142.8 141.9 99.4 (124.6 projected, +0.8) 8.16
2023.11 153.5 150.2 105.4 (124.6 projected, +0.0) 12.20
2023.12 151.1 146.4 114.2 (121.2 projected, -3.4) 9.60
2024.01 149.1 (1)   21.6 (2A) / 95.9 (2B) / 134.6 (2C) (117.9 projected, -3.3) (5.7)
2024.02       (117.1 projected, -0.8)  
2024.03       (116.6 projected, -0.5)  
2024.04       (116.6 projected, +0.0)  
2024.05       (117.0 projected, -0.8)  
2024.06       (114.9 projected, -2.1)  

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: 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 January 3, 2024

The relatively low solar activity during the last months of 2023 significantly increased the possibility that solar cycle 25 has already peaked. Whether the first peak in June 2023 will be the actual solar max will not be known for some time. Due to the relatively high solar activity early in 2023 it is unlikely there will be another solar max candidate, if at all, until at least May 2024. Both the northern and southern polar fields, as well as the averaged total field, have already reversed polarities.

--------------------------------------------------------------------------------------

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.