Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 31, 2015 at 04:05 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 quiet to active on July 30. Solar wind speed at SOHO ranged between 326 and 410 km/s. A geomagnetic disturbance began after 15h UT, the most likely source is a co-rotating interaction region ahead of a high speed stream from CH679.

Solar flux at 20h UTC on 2.8 GHz was 102.0 (decreasing 10.3 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 120.1. The Potsdam WDC planetary A index was 10 (STAR Ap - based on the mean of three hour interval ap indices: 10.3). Three hour interval K indices: 22112343 (planetary), 12122333 (Boulder).

The background x-ray flux is at the class B2 level.

At the time of counting spots (see image time), spots were observed in 10 active regions using 2K resolution (SN: 191) and 9 active regions using 1K resolution (SN: 131) SDO images on the visible solar disk.

Region 12389 [S11W20] decayed slowly and quietly.
Region 12390 [S15W52] decayed further with only rudimentary penumbra remaining on a few spots.
Region 12391 [N07E32] was quiet and stable.
Region 12392 [S04E39] was quiet and stable.
New region 12393 [N17E48] rotated into view on July 27 and was numbered by SWPC 3 days later.
New region 12394 [N11E68] rotated into view on July 29 and received its NOAA number the next day.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4647 [N16E10] developed slowly and quietly.
S4652 [S16E12] was quiet and stable.
New region S4653 [S25E34] emerged with an east west oriented inversion line.
New region S4654 [S09E16] emerged with a few spots.

C2+ flares:

Magnitude Peak time (UTC) Location AR Recorded by Comment
           

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

Coronal mass ejections (CMEs)

July 28-30: 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 trans equatorial coronal hole (CH679) was in an Earth facing position on July 28-29.

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 to fair.

Forecast

The geomagnetic field is expected to be quiet to active on July 31 and August 1 due to effects from CH679. Quiet to unsettled is likely on August 2.

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
12389 2015.07.23
2015.07.24
1 10 2 S12W20 0010 AXX BXO  
12390 2015.07.24 10 23 8 S15W53 0070 DSO DRI

 

12391 2015.07.26
2015.07.27
2 7 5 N06E31 0060 HAX CAO area: 0090
S4644 2015.07.26       S03W36            
12392 2015.07.27
2015.07.29
1 2 1 S05E37 0000 AXX CRO  
12393 2015.07.27
2015.07.30
8 13 8 N16E45 0010 DAO DRO area: 0090
S4647 2015.07.27   24 11 N16E10 0050   BXO images/AR_S4647_20150730_2345.png images/AR_S4647_20150729_2345.png  
S4648 2015.07.28       S22E54          
12394 2015.07.29
2015.07.30
1 2 2 N12E65 0120 HSX HHX area:0260

location: N11E68

S4650 2015.07.29       S11W40          
S4652 2015.07.29   4 1 S16E12 0008   AXX  
S4653 2015.07.30   2   S25E34 0004   BXO    
S4654 2015.07.30   4 3 S09E16 0018   CRO    
Total spot count: 23 91 41  
Sunspot number: 83 191 131  (total spot count + 10 * number of spotted regions)
Weighted SN: 43 118 68  (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): 91 105 111 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 (107.3)   66.2 (2A) / 68.4 (2B) / 84.9 (2C) (74.4 projected, -3.6) (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).
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.