Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 5, 2015 at 05:30 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 (July 3, 2015)
Solar cycle Solar cycles 23-24 (July 1, 2015) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24 progress (July 1, 2015) Noon SDO sunspot count 1K Reference: 4K (large file) (*)
  Solar cycles 1-23 - Solar Cycles 1-24 overview (new) POES auroral activity level October 2009 - December 2012
  Comparison of cycles 21, 22, 23 and 24 (July 1, 2015) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12, 13, 14, 16 and 24 (July 1, 2015) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs solar cycles (June 8, 2015)  

Recent activity

The geomagnetic field was quiet to minor storm on July 4, after noon under the influence of a high speed stream associated with CH675. Solar wind speed at SOHO ranged between 285 and 558 km/s.

Solar flux at 20h UTC on 2.8 GHz was 116.8 (decreasing 20.5 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 125.9. The Potsdam WDC planetary A index was 17 (STAR Ap - based on the mean of three hour interval ap indices: 17.1). Three hour interval K indices: 11013355 (planetary), 12123355 (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 11 active regions using 2K resolution (SN: 228) and 10 active regions using 1K resolution (SN: 151) SDO images on the visible solar disk.

Region 12373 [N16W13] decayed slowly and quietly.
Region 12375 [S10E05] was quiet and stable.
Region 12376 [N12E02] decayed slowly and quietly.
Region 12378 [S17E44] decayed and lost all umbrae on the trailing spots.
Region 12379 [S14E35] developed slowly and quietly.
New region 12380 [N09W28] emerged on July 3 and was numbered by SWPC the next day as the region began to decay.
New region 12381 [N15E59] rotated into view on July 3 and developed further on July 4 when the region was numbered by SWPC.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4587 [N08E23] reemerged with penumbra spots.
S4591 [S15W62] ewas quiet and stable.
New region S4593 [S04E17] emerged early in the day with penumbra spots.
New region S4594 [N07E80] rotated into view with a penumbra spot.

C2+ flares:

Magnitude Peak time (UTC) Location AR Recorded by Comment
           

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

Coronal mass ejections (CMEs)

July 2-4: 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 (CH675) rotated across the central meridian on July 1-2. A recurrent trans equatorial coronal hole (CH676) will likely rotate into an Earth facing position on July 7-8.

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 minor storm on July 5-6 due to effects from CH675 and a co-rotating interactive region and quiet to unsettled on July 7.

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
12374 2015.06.26
2015.06.28
      N10W85            
12373 2015.06.27
2015.06.28
8 25 8 N16W14 0100 CSO CAO images/AR_12373_20150704_2345.png images/AR_12373_20150703_2345.png

 

12376 2015.06.28
2015.06.30
7 31 12 N12E02 0090 DAO DAO  
12375 2015.06.28
2015.06.29
1 5 4 S10E04 0040 HSX CAO area: 0110
S4581 2015.06.30       N12W47          
12377 2015.07.01
2015.07.02
1     S10W65 0010 AXX     spotless
12379 2015.07.01
2015.07.03
5 21 9 S14E33 0020 CRO DRI area: 0050

location: S14E35

12378 2015.07.01
2015.07.02
4 12 7 S16E44 0090 CSO CSO

area: 0110

S4587 2015.07.02   3 1 N10E25 0007   BXO    
S4588 2015.07.02       S22W50            
12381 2015.07.03
2015.07.04
4 10 5 N16E57 0030 CRO DAO area: 0110

location: N15E59

S4590 2015.07.03       N17E47          
S4591 2015.07.03   5 1 S15W62 0010   BXO  
12380 2015.07.03
2015.07.04
1 3 2 N08W29 0010 HRX CRO  
S4593 2015.07.04   2 2 S04E17 0010   BXO    
S4594 2015.07.04   1   N07E80 0001   AXX    
Total spot count: 31 118 51  
Sunspot number: 111 228 151  (total spot count + 10 * number of spotted regions)
Weighted SN: 60 149 82  (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): 122 125 128 k * (sunspot number)
As of July 1, 2015: k = 1.1 for SWPC, k = 0.55 for MSN 2K, k = 0.85 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
2014.01 157.4 152.4 117.0 109.3 (+1.7) 5.44
2014.02 170.3
(cycle peak)
166.3 146.1 (cycle peak) 110.5 (+1.2) 10.70
2014.03 149.9 148.5 128.7 114.3 (+3.8) 4.88
2014.04 143.9 144.8 112.5 116.4 (+2.1) (solar max) 7.88
2014.05 129.7 132.9 112.5 115.0 (-1.4) 5.75
2014.06 122.0 125.8 102.9 114.1 (-0.9) 6.72
2014.07 137.4 141.8 100.2 112.8 (-1.3) 4.50
2014.08 124.7 127.9 106.9 108.7 (-4.1) 7.71
2014.09 146.6 148.1 130.0 102.5 (-6.2) 9.78
2014.10 153.4 152.9 90.0 98.0 (-4.5) 8.96
2014.11 154.8 151.4 103.6 95.7 (-2.3) 9.33
2014.12 158.7 153.8 112.9 93.3 (-2.4) 11.24
2015.01 141.9 137.3 97.6 (91.1 projected, -2.2) 9.46
2015.02 129.1 126.0 67.8 (89.8 projected, -1.3) 9.92
2015.03 125.9 124.6 56.8 (87.3 projected, -2.5) 16.14
2015.04 128.8 129.7 78.0 (83.9 projected, -3.4) 10.73
2015.05 120.0 122.6 90.0 (81.3 projected, -2.6) 8.29
2015.06 122.3 126.1 68.3 (78.0 projected, -3.3) 12.8
2015.07 (113.1)   10.5 (2A) / 81 (2B) / 92.0 (2C) (74.4 projected, -3.6) (6.4)

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.