Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 14, 2024 at 09:15 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 13. Solar wind speed at SOHO ranged between 318 and 427 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 185.4 - increasing 30.8 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 158.11. 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 2 (STAR Ap - based on the mean of three hour interval ap indices: 1.9). Three hour interval K indices: 00011001 (planetary), 01012211 (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 17 active regions using 2K resolution (SN: 351) and in 16 active regions using 1K resolution (SN: 253) SDO/HMI images.

Region 13539 [N11W80] decayed further and was mostly quiet. C1 flares: C1.7 @ 08:01 UT
Region 13540 [S18W36] was mostly quiet and stable. The westernmost spots of AR 13541 became part of AR 13540.
Region 13541 [S22W33] developed further in the trailing spot section and produced a number of low level C flares. C1 flares: C1.8 @ 05:05, C1.7 @ 21:27, C1.6 @ 22:04, C1.7 @ 22:13 UT
Region 13544 [N19W20] decayed slowly and quietly.
Region 13545 [S05E16] was mostly quiet and stable.
Region 13546 [S24W04] decayed slowly and quietly.
Region 13547 [N18W09] decayed slowly and was mostly quiet.
Region 13548 [N10E28] decayed slowly and quietly.
Region 13549 [S21E49] developed slowly with a number of tiny trailing spots forming. C1 flares: C1.7 @ 20:12 UT
Region 13550 [S18E10] decayed slowly and quietly.
Region 13551 [N26E38] decayed slowly and quietly.
Region 13552 [S22W28] decayed slowly and quietly.
New region 13553 [N05E68] rotated into view with a large penumbra.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9303 [S11W20] was quiet and stable.
New region S9321 [N11E06] emerged with tiny spots.
New region S9323 [N07E81] rotated into view with a few spots. C1 flares: C1.7 @ 18:56 UT
New region S9324 [S18E64] rotated into view with tiny spots.

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.6 00:59 northwest limb   GOES16  
C2.6 01:37   13541 GOES16  
C2.7 02:47 northwest limb   GOES16  
C3.0 03:21   13539 GOES16  
C2.8 03:54   S9323 GOES16  
C2.7 04:21   S9323 GOES16  
C2.1 08:41   13539 GOES16 simultaneous flare in AR 13553
C2.2 12:34   13539 GOES16  
C2.4 12:57   13541 GOES16  
C2.3 13:24   13553 GOES16  
C2.5 15:49   13541 GOES16  
C2.2 17:18   13541 GOES16  
C2.4 20:51   13549 GOES16  
C2.3 23:26 S21W35 13541 GOES16  

Coronal mass ejections (CMEs)

January 11-13: 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 northern hemisphere coronal hole (CH1197) rotated across the central meridian on January 13.

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 14-15. Quiet to active conditions are possible on January 16-17 due to effects from CH1197.

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
13541 2024.01.04
2024.01.05
4 13 7 S22W33 0070 DAO DAO beta-gamma

area: 0140

13540 2024.01.04
2024.01.05
13 34 21 S18W37 0080 DAI CSI location: S18W36

area: 0130

S9297 2024.01.04       S06W52          
13539 2024.01.05 3 6 3 N13W82 0110 CAO CRO

location: N11W80

area: 0070

13544 2024.01.05
2024.01.07
1 5 4 N18W24 0010 AXX AXX area: 0015
S9303 2024.01.06   9 3 S11W20 0020   BXO  
13545 2024.01.08
2024.01.09
3 17 5 S06E17 0250 CHO CHO area: 0340

location: S05E16

13546 2024.01.08
2024.01.09
9 24 13 S24W03 0040 CRO DRI

area: 0070

location: S24W04

S9310 2024.01.09       N06W56            
S9311 2024.01.09       N19W05            
13550 2024.01.09
2024.01.12
1 3 1 S18E09 0010 AXX BXO location: S18E10
13552 2024.01.09
2024.01.12
5 8 6 S22W25 0010 CAO CRO location: S22W28

area: 0040

13547 2024.01.10
2024.01.11
6 10 5 N18W09 0030 CAO DRO

area: 0050

13551 2024.01.10
2024.01.12
3 7 3 N26E39 0010 BXO BXO area: 0015

location: N26E38

13548 2024.01.10
2024.01.12
5 9 7 N12E28 0070 DAO DAO location: N10E28

area: 0090

13549 2024.01.10
2024.01.12
7 22 10 S21E50 0180 DSI CHI location: S21E49

area: 0400

S9318 2024.01.11       S10W58            
S9319 2024.01.12       N35E19          
13553 2024.01.13
2024.01.13
1 4 2 N05E68 0120 HSX CKO   area: 0270
S9321 2024.01.13   4 2 N11E06 0010   BXO    
S9323 2024.01.13   3 1 N07E81 0090   CAO    
S9324 2024.01.13   3   S18E64 0003   BXO    
Total spot count: 61 181 93  
Sunspot number: 191 351 253  (total spot count + 10 * number of spotted regions)
Weighted SN: 114 243 155  (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): 210 193 202  

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
2024.01 165.1 (1)   55.5 (2A) / 132.2 (2B) / 150.6 (2C) (117.9 projected, -3.3) (5.0)
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.