Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 16, 2015 at 06:05 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 15 under the influence of a high speed stream associated with CH672. Solar wind speed at SOHO ranged between 466 and 573 km/s.

Solar flux at 20h UTC on 2.8 GHz was 134.8 (increasing 24.5 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 127.1. The Potsdam WDC planetary A index was 12 (STAR Ap - based on the mean of three hour interval ap indices: 11.5). Three hour interval K indices: 22234332 (planetary), 2334332* (Boulder).

The background x-ray flux is at the class C1 level.

At the time of counting spots (see image time), spots were observed in 9 active regions using 2K resolution (SN: 170) and 7 active regions using 1K resolution (SN: 112) SDO images on the visible solar disk.

Region 12365 [S12W60] was quiet and stable.
Region 12367 [S20E18] was mostly quiet and stable and currently has a simple magnetic layout.
Region 12369 [N05E31] developed slowly and was quiet.
Region 12370 [N18E09] decayed slowly and quietly.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4541 [N16W55] decayed slowly and quietly.
S4543 [S11W13] regained leader spots and was quiet.
S4544 [S19W58] decayed slowly and quietly.
S4545 [N18E38] developed slowly and quietly.
New region S4554 [N11E81] rotated partly into view revealing a large spot. The region produced 2 C flares during the day and may be capable of producing an M class flare.
New region S4555 [N27W12] was observed with a penumbra spot.

C2+ flares:

Magnitude Peak time (UTC) Location AR Recorded by Comment
C2.1 07:54 S09W70 12368 SDO/EVE C1.7 @ GOES15
C2.5 10:32 N10E90 S4554 GOES15  
C2.9 21:21 N11E85 S4554 SDO/EVE  

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

Coronal mass ejections (CMEs)

June 13-15: 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]

A recurrent northern hemispere coronal hole (CH673) will likely rotate into an Earth facing position on June 20-21. CH673 did not cause a significant geomagnetic disturbance during the previous rotation.

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 fair.

Forecast

The geomagnetic field is expected to be quiet to unsettled on June 16 and quiet on June 17-18.

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
12361 2015.06.03
2015.06.04
      N18W88           location: N21W74
12362 2015.06.03
2015.06.04
      N07W78        

 

12365 2015.06.05
2015.06.06
4 4 2 S13W61 0090 CSO CAO

 

12364 2015.06.05
2015.06.06
      S07W64        

location: S05W57

12366 2015.06.06
2015.06.07
1     N16W57 0000 AXX     spotless, SWPC is reporting the spot in AR S4541
S4531 2015.06.08       S08W45          
S4533 2015.06.09       S32W28            
12368 2015.06.09
2015.06.13
1     S06W79 0000 AXX     spotless
12367 2015.06.10
2015.06.11
29 37 23 S20E20 0400 EKC EKC

area: 0580

S4538 2015.06.11       N18W47            
S4539 2015.06.11       S10E14            
12369 2015.06.12
2015.06.13
2 9 4 N05E31 0010 BXO CRO  
S4541 2015.06.12   1   N16W55 0002   AXX  
S4542 2015.06.12       N11W34            
S4543 2015.06.12   8 2 S11W13 0015   AXX images/AR_S4543_20150615_2345.png  
S4544 2015.06.12   1 1 S19W58 0003   AXX  
12370 2015.06.12
2015.06.14
10 15 7 N18E10 0020 CRO BXO area: 0030
S4548 2015.06.13       N08W21          
S4550 2015.06.14       S18W25          
S4551 2015.06.14       N16W24          
S4553 2015.06.14       S22E04          
S4554 2015.06.15   4 3 N11E81 0340   HHX    
S4555 2015.06.15   1   N27W12 0002   AXX    
Total spot count: 47 80 42  
Sunspot number: 107 170 112  (total spot count + 10 * number of spotted regions)
Weighted SN: 65 108 70  (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): 64 60 62 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 (126.9)   47.8 (2A) / 95.5 (2B) / 64.4 (2C) (49.6 projected, -2.8) (8.6)

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.