Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 9, 2018 at 05:55 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 2, 2018)
Solar cycle Solar cycles 23-24 (January 1, 2018) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24 progress (January 1, 2018) / Cycle 25 spots Noon SDO sunspot count 1K image / 4K (*)
  Solar cycles 1-24 (July 17, 2015) POES auroral activity level October 2009 - December 2012]
  Comparison of cycles 21, 22, 23 and 24 (January 1, 2018) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12, 13, 14, 16 and 24 (January 1, 2018) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (January 7, 2018)  

Recent activity

The geomagnetic field was quiet to unsettled on January 8. Solar wind speed at SOHO ranged between 285 and 531 km/s. A weak solar wind shock was recorded at SOHO at 05:59 UT and appears to have been associated with the arrival of a high speed stream from CH845.

Solar flux at 20h UTC on 2.8 GHz was 70.3 (decreasing 1.1 over the previous solar rotation). The average 90 day 10.7 flux at 1 AU was 70.5. The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.0). Three hour interval K indices: 01213322 (planetary), 00324421 (Boulder)

The background x-ray flux is at the class A3 level.

At the time of counting spots (see image time), spots were observed in 4 active regions using 2K resolution (SN: 55) and in 1 active region using 1K resolution (SN: 14) SDO images on the visible solar disk.

New region 12694 [S32W03] emerged on January 7 and was numbered the next day by SWPC as the region developed slowly.

Spotted regions not numbered (or interpreted differently) by SWPC:
S5873 [S08W09] reemerged with tiny spots.
S5877 [S07W18] reemerged with tiny spots.
New region S5880 [N01W18] emerged with a tiny spot.

C2+ flares:

Magnitude Peak time (UT) Location AR Recorded by Comment
           

Coronal mass ejections (CMEs)

January 6-8: No obviously Earth directed CMEs were observed in available LASCO imagery.

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 extension (CH845) of the northern polar coronal hole was Earth facing on January 4-5. A small recurrent southern hemisphere coronal hole (CH846) rotated across the central meridian on January 6, CH846 did not cause a disturbance during the previous rotation. A recurrent trans equatorial coronal hole (CH847) will likely become Earth facing on January 9-11.

Propagation

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

Forecast

The geomagnetic field is expected to be quiet to unsettled on January 9 due to effects from CH845 and quiet on January 10-11.

Coronal holes (1) Coronal mass ejection (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 numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC. 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.

Active region Date numbered
detected
Spot count Location at midnight Area Classification SDO / HMI 4K continuum
image with magnetic polarity overlays
Comment
SWPC Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
S5872 2018.01.03       N22W52            
S5873 2018.01.04   2   S08W09 0003   BXO    
S5876 2018.01.05       N07W14            
S5877 2018.01.06   5   S07W18 0006   BXO    
12694 2018.01.07
2018.01.08
3 7 4 S32W03 0010 BXO DRO   area: 0040
S5880 2018.01.08   1   N01W18 0002   AXX    
Total spot count: 3 15 4  
Sunspot number: 13 55 14  (total spot count + 10 * number of spotted regions)
Weighted SN: 3 18 7  (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): 14 30 11 k * (sunspot number)
As of May 7, 2016: k = 1.1 for SWPC, k = 0.55 for MSN 2K, k = 0.80 for MSN 1K (MSN=Magnetic Sunspot Number)

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO) (4)
Smoothed sunspot number (4) Average ap
(3)
Measured 1 AU
2014.02 170.3
(cycle peak)
166.3 146.1 (cycle peak) 110.5 (+1.2) 10.70
2014.04 143.9 144.8 112.5 116.4 (+2.1) (solar max) 7.88
2016.07 86.0 88.9 32.5 38.6 (-3.0) 9.43
2016.08 85.0 87.1 50.7 36.0 (-2.6) 9.61
2016.09 87.7 88.7 44.7 33.3 (-2.7) 14.54
2016.10 86.1 85.6 33.6 31.4 (-1.9) 15.33
2016.11 78.6 76.9 21.4 29.9 (-1.5) 9.11
2016.12 75.1 72.8 18.9 28.5 (-1.4) 9.34
2017.01 77.3 74.9 25.8 27.9 (-0.6) 9.45
2017.02 76.8 75.0 26.1 26.6 (-1.3) 9.58
2017.03 74.6 73.9 17.7 25.8 (-0.8) 14.20
2017.04 80.3 80.8 32.6 24.9 (-0.9) 11.70
2017.05 73.6 75.2 18.8 23.4 (-1.5) 8.09
2017.06 74.7 77.1 19.4 22.3 (-1.1) 6.08
2017.07 77.4 79.9 18.3 (21.2 projected, -1.1) 8.97
2017.08 77.9 79.8 33.1 (19.5 projected, -1.7) 10.66
2017.09 91.3 92.3 43.6 (18.3 projected, -1.2) 18.22 (cycle peak)
2017.10 76.4 75.6 13.2 (16.8 projected, -1.5) 10.30
2017.11 72.2 70.6 5.7 (15.3 projected, -1.5) 10.06
2017.12 71.6 69.3 8.2 (14.5 projected, -0.8) 7.1
2018.01 (69.7)   1.9 (2A)/ 7.4 (2B) / 10.9 (2C) (13.5 projected, -1.0) (4.2)

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz.
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) Updated to new data set from WDC-SILSO on July 1, 2015

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.