Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 13, 2024 at 10:10 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 (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

Recent activity

The geomagnetic field was very quiet on January 12. Solar wind speed at SOHO ranged between 373 and 459 km/sec. The high latitude magnetometer at Andenes recorded quiet to unsettled levels.

Solar flux density measured at 20h UT on 2.8 GHz was 186.4 - increasing 37.4 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 158.17. 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 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.4). Three hour interval K indices: 01011111 (planetary), 01121221 (Boulder), 00000013 (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: 362) and in 13 active regions using 1K resolution (SN: 247) SDO/HMI images.

Region 13539 [N10W67] decayed slowly and lost the magnetic delta structure.
Region 13540 [S17W21] was mostly quiet and stable.
Region 13541 [S21W22] developed in the trailing spot section as new flux emerged. The region has polarity intermixing and may be capable of generating a minor M class flare.
Region 13544 [N18W09] was quiet and stable.
Region 13545 [S05E29] was quiet and stable.
Region 13546 [S23E11] has weak polarity intermixing and was mostly quiet.
Region 13547 [N19E06] has polarity intermixing and produced the only M flare of the day.
New region 13548 [N11E41] rotated into view on January 10, then developed significantly on January 11-12 with SWPC numbering the region on Jan.12. The region produced a few C flares early in the day.
New region 13549 [S21E61] rotated into view on January 10 and was numbered by SWPC 2 days later. The region was mostly quiet.
New region 13550 [S16E22] rotated into view on January 9 and received its NOAA number 3 days later.
New region 13551 [N27E52] rotated into view on January 10 and was noticed by SWPC 2 days later.
New region 13552 [S22W14] emerged on January 9, and was not numbered by SWPC until 3 days later due to a poor initial interpretation which grouped the spots with AR 13541.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9297 [S06W39] reemerged with a tiny spot.
S9303 [S10W06] was quiet and stable.
S9310 [N06W17] was quiet and stable.
New region S9319 [N35E32] emerged with a tiny spot.

A large spot (AR S9320) rotated into view at N05 late in the day, however was not numbered then due to missing SDO/HMI imagery.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C3.6 00:31   13543 GOES18  
C3.2 01:55   13538 GOES18  
C4.3 02:25   13538 GOES18  
C3.7 02:44   13549 GOES18  
M1.0 02:58 N18E20 13547 GOES18  
C3.5 03:17   13539 GOES18  
C5.8 03:59 N10W57 13539 GOES18  
C6.0 04:15 N12E56 13548 GOES18  
C3.2 04:58   13548 GOES18  
C3.8 06:08 N11E51 13548 GOES18  
C4.4 06:28   13539 GOES18  
C2.3 08:08   13539 GOES18  
C3.7 08:20   13539 GOES18  
C2.4 08:47   13548 GOES18  
C5.9 10:06 S22W13 13541 GOES18  
C3.3 10:32   13538 GOES18  
C3.3 10:57   13541 GOES18  
C3.9 11:15   13538 GOES18  
C4.5 11:47   13541 GOES18  
C2.4 13:03   13539 GOES18  
C3.3 15:38   13539 GOES16  
C2.5 16:53   13546 GOES16  
C4.7 17:21   13538 GOES16  
C2.5 21:57   13548 GOES16  
C3.8 22:40   13538 GOES16  
C3.4 23:38   S9279 GOES16  

Coronal mass ejections (CMEs)

January 10-12: No obviously Earth directed CME observed.
January 9: A partial halo CME was observed after a large filament eruption in the southeast quadrant. A weak shock from this CME is possible on January 13.

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 northern hemisphere coronal hole (CH1197) will rotate across the central meridian on January 13-14.

Propagation

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

Forecast

The geomagnetic field is expected to be quiet on January 13-15 with a slight chance of unsettled to active conditions on January 13-14 due to to CME effects.

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
S9279 2023.12.31       N09W80          
13537 2024.01.01
2024.01.02
      N18W80          

location: N17W84

S9291 2024.01.03       N15W46            
S9293 2024.01.04       N27W40            
13541 2024.01.04
2024.01.05
12 25 16 S22W22 0050 DAI DRI beta-gamma

location: S21W22

area: 0110

13540 2024.01.04
2024.01.05
8 27 10 S17W22 0060 CAO CAO location: S17W21

area: 0130

S9297 2024.01.04   1   S06W39 0002   AXX    
13539 2024.01.05 8 30 17 N10W69 0130 DAO DAI

location: N10W67

area: 0220

13542 2024.01.05       N18W85           this was the eastern part of AR 13537
13544 2024.01.05
2024.01.07
1 7 4 N18W09 0010 AXX CRO area: 0020
S9303 2024.01.06   9 4 S10W06 0015   BXO  
13545 2024.01.08
2024.01.09
4 14 7 S07E30 0160 CHO CHO area: 0380

location: S05E29

13546 2024.01.08
2024.01.09
11 25 18 S24E09 0060 DAI DRI beta-gamma

area: 0140

location: S23E11

S9310 2024.01.09       N06W43            
S9311 2024.01.09       N19E08            
13550 2024.01.09
2024.01.12
3 9 4 S16E21 0010 BXO BXO  
13552 2024.01.09
2024.01.12
5 18 11 S23W14 0030 DAO DAO location: S22W14

area: 0080

13547 2024.01.10
2024.01.11
5 17 9 N19E06 0050 CSO DAO beta-gamma

area: 0120

13551 2024.01.10
2024.01.12
3 8 5 N25E50 0010 BXO CRO area: 0030

location: N27E52

13548 2024.01.10
2024.01.12
5 16 8 N12E41 0090 DSO DAI beta-gamma
13549 2024.01.10
2024.01.12
3 5 4 S20E62 0140 DSO DSO location: S21E61

area: 0300

S9318 2024.01.11       S10W45          
S9319 2024.01.12   1   N35E32 0001   AXX    
Total spot count: 68 212 107  
Sunspot number: 188 362 237  (total spot count + 10 * number of spotted regions)
Weighted SN: 118 264 159  (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): 207 199 190  

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
2024.01 163.4 (1)   49.3 (2A) / 127.3 (2B) / 147.3 (2C) (117.9 projected, -3.3) (5.2)
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.

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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.