Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 23, 2015 at 05:25 UT

Charts (* = updated daily) Data and archive
  Solar wind (*) Solar and geomagnetic data - last month (*)
  Electron fluence (*) Archived daily reports and monthly data from 2003.01 (June 1, 2015)
Solar cycle Solar cycles 23-24 (June 1, 2015) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24 progress (June 1, 2015) Noon SDO sunspot count 1K Reference: 4K (large file) (*)
  Solar cycles 1-20 POES auroral activity level October 2009 - December 2012
  Comparison of cycles 21, 22, 23 and 24 (June 1, 2015) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 10, 12, 13, 14, 16 and 24 (June 1, 2015) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs solar cycles (June 8, 2015)  

Recent activity

The geomagnetic field was quiet to very severe storm on June 22. Solar wind speed at SOHO ranged between 335 and 712 km/s. A sudden increase in solar wind speed was observed at 04:52 UT at SOHO, the arrival of the June 19 CME. A strong solar wind shock was recorded at 18:01 UT at SOHO, this was the arrival of the CME observed early on June 21. The interplanetary magnetic field was very strongly southwards just after the shock and this caused very severe geomagnetic storming.

Solar flux at 17h UTC on 2.8 GHz was 130.1 (increasing 35.6 over the last solar rotation, the measurement at 20h was flare enhanced). The 90 day 10.7 flux at 1 AU was 128.7. The Potsdam WDC planetary A index was 55 (STAR Ap - based on the mean of three hour interval ap indices: 55.4). Three hour interval K indices: 23435585 (planetary), 24435585 (Boulder).

The background x-ray flux is at the class B6 level.

At the time of counting spots (see image time), spots were observed in 7 active regions using 2K resolution (SN: 144) and 4 active regions using 1K resolution (SN: 84) SDO images on the visible solar disk.

Region 12367 [S19W79] rotated to the southwest limb and produced a few C flares. A minor M class flare is possible while this region is near the limb.
Region 12371 [N11W12] lost some penumbral area in the leading spot section. There is still a large magnetic delta in the trailing penumbra and further major flares possible.
New region 12372 [N20W67] emerged with penumbra spots.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4557 [N20W29] was quiet and stable.
S4563 [S09E24] was quiet and stable.
S4564 [N14E61] decayed and could soon become spotless.
New region S4567 [S09W18] was observed with a penumbra spot.

C2+ flares:

Magnitude Peak time (UTC) Location AR Recorded by Comment
C3.2 (LDE) 02:42 N10W17 12371 GOES15  
C7.5/1N 05:19 S19W68 12367 GOES15  
C3.9 17:27 N11W07 12371 GOES15  
M6.5/2B (LDE) 18:23 N12W08 12371 GOES15 full halo CME
C4.7 21:00   12367 SDO/EVE  

Flare activity (SDO/EVE/ESP XRS-B proxy)

Coronal mass ejections (CMEs)

June 20: No obviously Earth directed CMEs were observed.
June 21
: A halo CME was observed after an M2 flare in AR 12371 early in day. The CME reached Earth on June 22.
June 22: A full halo CME was observed in association with an M6 flare in AR 12371. The CME could reach Earth on June 24.

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 northern hemispere coronal hole (CH673) was in an Earth facing position on June 19-20. CH673 did not cause a significant geomagnetic disturbance during the previous rotation. CH673 decreased in size June 16-18, but became larger following a filament eruption in the southern hemisphere on June 19.

Propagation

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

Forecast

The geomagnetic field is expected to be unsettled to severe storm on June 23 due to effects from the CME which arrived on June 22. Another CME arrival on June 24 could cause unsettled to major storm conditions that day and on June 25.

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) 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
12367 2015.06.10
2015.06.11
9 11 7 S19W77 0240 EAC DAC

beta-gamma

12369 2015.06.12
2015.06.13
      N06W72          

location: N06W61

12371 2015.06.15
2015.06.16
34 55 34 N13W13 1070 FKC FKC beta-gamma-delta

location: N11W12

S4557 2015.06.16   2   N20W29 0003   AXX  
S4558 2015.06.16       S10W58            
S4560 2015.06.19       S23W03            
S4562 2015.06.20       S03W38            
S4563 2015.06.20   2 1 S09E24 0006   AXX  
S4564 2015.06.21   1   N14E61 0001   AXX  
S4565 2015.06.21       S10E09          
12372 2015.06.22 4 2 2 N20W68 0010 BXO BXO    
S4567 2015.06.22   1   S09W18 0003   AXX    
Total spot count: 47 74 44  
Sunspot number: 77 144 84  (total spot count + 10 * number of spotted regions)
Weighted SN: 62 89 59  (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): 46 50 46 k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for MSN 2K, k = 0.55 for MSN 1K (MSN=Magnetic Sunspot Number)

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number Average ap
(3)
Measured 1 AU
2014.01 157.4 152.4 81.8 77.3 (+1.3) 5.44
2014.02 170.3
(cycle peak)
166.3 102.3 (cycle peak) 78.4 (+1.1) 10.70
2014.03 149.9 148.5 91.9 80.8 (+2.4) 4.88
2014.04 143.9 144.8 84.7 81.9 (+1.1) (solar max) 7.88
2014.05 129.7 132.9 75.2 80.5 (-1.4) 5.75
2014.06 122.0 125.8 71.0 79.7 (-0.8) 6.72
2014.07 137.4 141.8 72.5 78.5 (-1.2) 4.50
2014.08 124.7 127.9 74.7 75.5 (-3.0) 7.71
2014.09 146.6 148.1 87.6 70.8 (-4.7) 9.78
2014.10 153.4 152.9 60.6 67.3 (-3.5) 8.96
2014.11 154.8 151.4 70.1 65.4 (-1.9) 9.33
2014.12 158.7 153.8 78.0 (63.5 projected, -1.9) 11.24
2015.01 141.9 137.3 67.0 (61.3 projected, -2.2) 9.46
2015.02 129.1 126.0 44.8 (59.6 projected, -1.7) 9.92
2015.03 125.9 124.6 38.4 (57.2 projected, -2.4) 16.14
2015.04 128.8 129.7 54.4 (54.6 projected, -2.6) 10.73
2015.05 120.0 122.6 58.8 (52.4 projected, -2.2) 8.29
2015.06 (129.4)   67.2 (2A) / 91.6 (2B) / 61.1 (2C) (49.6 projected, -2.8) (10.1)

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). The official WDC-SILSO international sunspot number is typically 30-50% lower. 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.

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 the UTC day. Comments and suggestions are always welcome.

SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.