Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 19, 2024 at 07:30 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 quiet to unsettled on January 18 under the in fluence of weak effects from CH1197. Solar wind speed at SOHO ranged between 305 and 426 km/sec. The high latitude magnetometer at Andenes recorded quiet to minor storm levels.

Solar flux density measured at 20h UT on 2.8 GHz was 162.3 - decreasing 24.4 over the previous solar rotation. (Centered 1 year average SF at 1 AU - 183 days ago: 157.46. 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 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.1). Three hour interval K indices: 11121132 (planetary), 11222222 (Boulder), 21011155 (Andenes).

The background x-ray flux is at the class B8 level (GOES 16).

At the time of counting spots (see image time), spots were observed in 19 active regions using 2K resolution (SN: 330) and in 17 active regions using 1K resolution (SN: 228) SDO/HMI images.

Region 13545 [S06W51] was mostly quiet and stable.
Region 13549 [S20W14] was mostly quiet and stable.
Region 13551 [N27W23] was quiet and stable.
Region 13553 [N05E03] decayed slowly and produced several C flares. C1 flares: C1.3 @ 00:57, C1.7 @ 08:13, C1.4 @ 09:29, C1.9 @ 09:56, C1.5 @ 13:33 UT
Region 13554 [N07E11] decayed slowly and quietly.
Region 13555 [S11E29] was mostly quiet and stable. C1 flares: C1.3 @ 20:27 UT
Region 13556 [N16E39] was quiet and stable.
Region 13557 [S23E53] was quiet and stable.
New region 13559 [N27E59] rotated into view on January 17 and was numbered the next day by SWPC.
New region 13560 [S10E64] rotated into view on January 17 and got its NOAA number the following day.

Spotted regions not observed (or interpreted differently) by SWPC/USAF:
S9329 [S19E28] was quiet and stable.
S9332 [S15E29] developed as new flux emerged.
S9337 [S17W02] was quiet and stable.
S9338 [N16W00] was quiet and stable.
S9339 [N23W10] was quiet and stable.
New region S9341 [S11W02] emerged with tiny spots.
New region S9342 [S10E22] emerged with tiny spots.
New region S9343 [N22E57] emerged with tiny spots.
New region S9344 [S02E04] emerged with a tiny spot.

AR 13541 behind the southwest limb produced a C1.4 flare at 02:16, a C1.6 flare at 14:49 and a C1.3 flare at 16:46 UT
AR 13558 behind the southwest limb produced a C1.3 flare at 14:12 UT

C2+ flares:

Magnitude Peak time (UT) Location Source Recorded by Comment
C2.7 03:46   13553 GOES16  
C5.4 04:08   13553 GOES16  
C2.5 05:18   13553 GOES16  
C3.0 10:14   13540 GOES16  
C2.8 12:22   13553 GOES16  

Coronal mass ejections (CMEs)

January 16-18: 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. Another positive polarity northern hemisphere coronal hole (CH1198) was Earth facing on January 16-18.

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

Forecast

The geomagnetic field is expected to be quiet to unsettled on January 19 due to effects from CH1197. January 20-21 could see quiet to active levels due to effects from CH1198.

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
13545 2024.01.08
2024.01.09
2 4 3 S07W51 0180 HAX CKO area: 0420

location: S06W51

13546 2024.01.08
2024.01.09
      S24W73          

location: S23W69

13550 2024.01.09
2024.01.12
      S18W59           location: S18W55
13547 2024.01.10
2024.01.11
      N18W79          

location: N19W57

13551 2024.01.10
2024.01.12
  8 2 N26W24 0015   BXO

location: N27W23

13548 2024.01.10
2024.01.12
      N15W38         location: N12W36
13549 2024.01.10
2024.01.12
5 14 6 S21W14 0200 CAO CKO

area: 0360

location: S20W14

S9319 2024.01.12       N35W46            
13553 2024.01.13
2024.01.13
10 21 8 N05E03 0110 CAO CAO  
S9321 2024.01.13       N11W46            
13554 2024.01.13
2024.01.15
2 10 4 N07E12 0030 HRX HRX

location: N07E11

S9324 2024.01.13       S19E02            
13555 2024.01.14
2024.01.15
8 18 10 S11E31 0160 DAI DAI location: S11E42

area: 0300

S9326 2024.01.14       S10W55            
S9327 2024.01.14       N12W15            
S9328 2024.01.14       N21W18            
S9329 2024.01.15   3 2 S19E28 0008   BXO  
13556 2024.01.15
2024.01.16
2 6 4 N16E39 0090 HAX HSX

area: 0110

13557 2024.01.16
2024.01.16
  2   S13E46 0006   AXX

location: S23E53

S9332 2024.01.16   10 3 S15E25 0020   BXO  
S9333 2024.01.16       N11E23            
S9334 2024.01.16       N13W09            
13559 2024.01.17
2024.01.18
3 9 4 N27E59 0160 DSO EAO area: 0260
13560 2024.01.17
2024.01.18
1 3 1 S11E66 0020 HRX CRO location: S10E64
S9337 2024.01.17   9 3 S17W02 0025   AXX  
S9338 2024.01.17   5 2 N16W00 0009   AXX  
S9339 2024.01.17   9 3 N23W10 0020   AXX  
S9340 2024.01.17       N11E12          
S9341 2024.01.18   4 1 S11W02 0006   BXO    
S9342 2024.01.18   2   S10E22 0005   AXX    
S9343 2024.01.18   2 1 N22E57 0004   BXO    
S9344 2024.01.18   1 1 S02E04 0002   AXX    
Total spot count: 33 140 58  
Sunspot number: 113 330 238  (total spot count + 10 * number of spotted regions)
Weighted SN: 69 186 104  (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): 124 182 190  

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  176.4 182.2 160.0 (124.6 projected, -0.4) 8.15
2023.08  153.7 157.6 114.8 (124.1 projected, -0.5) 7.19
2023.09  154.4 156.0 134.2 (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
2024.01 168.5 (1)   79.8 (2A) / 137.4 (2B) / 153.9 (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.

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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.