Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 25, 2015 at 04:20 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 active on June 24 under the influence of CME effects. Solar wind speed at SOHO ranged between 474 and 785 km/s. A solar wind shock was observed at SOHO at 13:01 UT, the arrival of the June 22 CME. The interplanetary magnetic field was unimpressive during the hours after the shock. As the Bz component was mostly weakly northwards, the geomagnetic disturbance level actually decreased.

Solar flux at 20h UTC on 2.8 GHz was 109.5 (increasing 16.5 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 128.3. The Potsdam WDC planetary A index was 14 (STAR Ap - based on the mean of three hour interval ap indices: 14.4). Three hour interval K indices: 43433321 (planetary), 43443332 (Boulder).

The background x-ray flux is at the class B4 level.

At the time of counting spots (see image time), spots were observed in 1 active region using 2K resolution (SN: 55) and 1 active region using 1K resolution (SN: 28) SDO images on the visible solar disk.

Region 12371 [N11W38] decayed further losing spots, penumbral area and some magnetic complexity. The region has some polarity intermixing and a minor M class flare is possible during the decay phase.

C2+ flares:

Magnitude Peak time (UTC) Location AR Recorded by Comment
C5.6/1F 15:29 N15W34 12371 GOES15  

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

Coronal mass ejections (CMEs)

June 22: A full halo CME was observed in association with an M6 flare in AR 12371. The CME reached Earth on June 24.
June 23-24: No obviously Earth directed CMEs were 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]

No obvious coronal holes are currently in Earth facing positions.

Propagation

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

Forecast

The geomagnetic field is expected to be quiet to unsettled on June 25-26 due to weak CME effects and quiet on June 27.

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
12371 2015.06.15
2015.06.16
29 45 18 N11W40 0740 FKC FKC beta-gamma
S4557 2015.06.16       N20W55            
S4560 2015.06.19       S23W29            
S4563 2015.06.20       S09W02            
S4564 2015.06.21       N14E35            
S4565 2015.06.21       S10W17            
S4567 2015.06.22       S09W44            
S4568 2015.06.23       N32E09          
Total spot count: 29 45 18  
Sunspot number: 39 55 28  (total spot count + 10 * number of spotted regions)
Weighted SN: 39 55 28  (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): 23 19 15 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 (128.1)   70.5 (2A) / 88.1 (2B) / 59.3 (2C) (49.6 projected, -2.8) (13.3)

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.