Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 4, 2015 at 04:35 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 (May 9, 2015)  

Recent activity

The geomagnetic field was very quiet on June 3. Solar wind speed at SOHO ranged between 286 and 355 km/s.

Solar flux at 20h UTC on 2.8 GHz was 108.5 (decreasing 38.1 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 125.0. The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.0). Three hour interval K indices: 01111010 (planetary), 10132322 (Boulder).

The background x-ray flux is at the class B5 level.

At the time of counting spots (see image time), spots were observed in 9 active regions using 2K resolution (SN: 158) and 8 active regions using 1K resolution (SN: 114) SDO images on the visible solar disk.

Region 12356 [S15W18] decayed slowly and quietly.
Region 12357 [N09W24] was quiet and stable.
Region 12358 [S03E34] decayed slowly and quietly.
Region 12359 [S14W26] decayed slowly and quietly.
New region 12360 [N14E51] rotated into view on June 1 and was numbered by SWPC 2 days later when new flux emerged. C class flares are possible.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4518 [S18E12] reemerged with a penumbra spot.
New region S4521 [N17E77] rotated into view with a few spots.
New region S4522 [N06E83] rotated into view.
New region S4523 [S05E18] was observed with a penumbra spot.

C2+ flares:

Magnitude Peak time (UTC) Location AR Recorded by Comment
           

Flare activity according to SDO/EVE/ESP XRS-B proxy

Coronal mass ejections (CMEs)

June 1-3: 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 southern hemisphere coronal hole (CH671) will rotate into an Earth facing position on June 3-4.

Propagation

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

Forecast

The geomagnetic field is expected to be quiet on June 4-6. Quiet to active conditions are likely on June 7-8 due to effects from CH671.

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
S4501 2015.05.26       N12W39            
12359 2015.05.26
2015.06.01
5 10 6 S16W26 0010 BXO CRO  
12356 2015.05.27
2015.05.28
1 7 4 S16W20 0050 HAX CAO area: 0110

location: S15W18

12357 2015.05.28
2015.05.29
  5 2 N09W20 0010   AXX location: N09W24
S4514 2015.05.29       S19W46          
12358 2015.05.31 4 12 5 S03E30 0030 CSO BXI location: S03E34
S4517 2015.05.31       S03W23            
S4518 2015.06.01   1 1 S18E12 0003   AXX    
12360 2015.06.01
2015.06.03
5 25 12 N12E52 0050 DAO DAI location: N14E51
S4521 2015.06.03   5 3 N17E77 0080   DAO    
S4522 2015.06.03   2 1 N06E83 0010   BXO    
S4523 2015.06.03   1   S05E18 0002   AXX    
Total spot count: 15 68 34  
Sunspot number: 55 158 114  (total spot count + 10 * number of spotted regions)
Weighted SN: 30 86 52  (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): 33 55 63 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) 8.2
2015.06 (103.3)   4.4 (2A)/ 44.0 (2B) / 74.1 (2C) (49.6 projected, -2.8) (3.5)

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.