Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 20, 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 (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 1-24 (July 17, 2015) 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 (July 18, 2015)  

Recent activity

The geomagnetic field was very quiet on July 19. Solar wind speed at SOHO ranged between 273 and 295 km/s.

Solar flux at 20h UTC on 2.8 GHz was 99.4 (decreasing 30.7 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 123.2. The Potsdam WDC planetary A index was 2 (STAR Ap - based on the mean of three hour interval ap indices: 1.9). Three hour interval K indices: 00010000 (planetary), 11121222 (Boulder).

The background x-ray flux is at the class B3 level.

At the time of counting spots (see image time), spots were observed in 6 active regions using 2K resolution (SN: 111) and 5 active regions using 1K resolution (SN: 75) SDO images on the visible solar disk.

Region 12384 [S17W80] was quiet and stable.
Region 12386 [N10W19] was quiet and stable.
Region 12387 [N17E20] developed in the central part as new flux emerged. C flares are possible.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4620 [N18W31] decayed slowly and quietly.
New region S4627 [S19W22] emerged with a penumbra spot.
New region S4629 [N25E12] was observed with a penumbra spot.

A complex chain of filament eruptions was observed beginning just after midnight on July 19. The first filament eruption was observed beginning in the northwest quadrant. By 04 UT it extended into the southwestern quadrant and triggered activity in another filament. That filament began erupting just before 07 UT and eventually was the source of the C2 LDE observed peaking after 10 UT. The associated CME may have had a minor Earyh directed component.

C2+ flares:

Magnitude Peak time (UTC) Location AR Recorded by Comment
C2.1 (LDE) 10:40 SW quadrant   GOES15 filament eruption, CME, weak proton event

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

Coronal mass ejections (CMEs)

July 17-18: No obviously Earth directed CMEs were observed.
July 19: A CME associated with a C2 long duration event and an erupting filament in the southwest quadrant may have had a weak Earth directed component. If that is the case weak CME effects could be observed late on July 22 and on July 23.

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 small trans equatorial coronal hole (CH677) was in an Earth facing position on July 16-17.

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 July 20-22 with a chance of unsettled intervals on July 20 due to possible effects from CH677.

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
12384 2015.07.07
2015.07.08
1 1 1 S17W80 0060 HSX HAX  
S4610 2015.07.10       S04W39            
12386 2015.07.11
2015.07.12
4 21 9 N11W20 0060 HAX CAO area: 0100
S4615 2015.07.13       N07W53            
12387 2015.07.15
2015.07.16
11 23 13 N17E18 0100 DAI DAI  
S4620 2015.07.15   4   N18W31 0005   AXX  
S4621 2015.07.16       S20E04            
S4623 2015.07.17       S09E15          
S4624 2015.07.17       N11E37            
S4625 2015.07.17       S06W54            
S4626 2015.07.18       N12W59          
S4627 2015.07.19   1 1 S19W22 0003   AXX    
S4629 2015.07.19   1 1 N25E12 0003   AXX    
Total spot count: 16 51 25  
Sunspot number: 46 111 75  (total spot count + 10 * number of spotted regions)
Weighted SN: 31 66 40  (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): 51 61 64 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 (114.1)   49.1 (2A) / 80.1 (2B) / 80.4 (2C) (74.4 projected, -3.6) (8.8)

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.