Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 25, 2014 at 06:40 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update July 1, 2014)] [Cycle 24 progress (last update July 1, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update July 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update July 1, 2014)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update July 5, 2014)]

[POES auroral activity level October 2009 - December 2012]
[Solar polar fields vs solar cycles - updated July 18, 2014]
[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]

Recent activity

The geomagnetic field was quiet on July 24. Solar wind speed at SOHO ranged between 284 and 359 km/s.

Solar flux at 20h UTC on 2.8 GHz was 104 (decreasing 0.2 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 132.7. The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.4). Three hour interval K indices: 11121111 (planetary), 12122321 (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 7 active regions using 2K resolution (SN: 126) and 6 active regions using 1K resolution (SN: 89) SDO images on the visible solar disk.

Region 12119 [S21W66] decayed slowly and quietly.
Region 12121 [N07E43] gained a few spots and has polarity intermixing. C flares are possible, as is a minor M class flare.
Region 12122 [S12E25] decayed slowly and quietly.
Region 12123 [S14E40] was quiet and stable.

Spotted regions not numbered (or interpreted differently) by SWPC:
New region S3667 [N09W14] emerged early in the day and decayed slowly during the latter half of the day.
New region S3668 [S09E44] emerged early in the day.
New region S3669 [S12W17] was observed with penumbra spots.

C2+ Flares (GOES):

Magnitude Peak time (UTC) Location AR
C2.1/1F 01:51 N10E62 12121

Coronal mass ejections (CMEs)

July 22-24: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.

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 (CH628) rotated into an Earth facing position on July 23-24.

Coronal hole map

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 on July 25-26 and quiet to unsettled on July 27. On July 25 there's a chance of a few unsettled intervals should a stream from CH627 reach Earth. Unsettled intervals are possible on July 27 due to effects from CH628.

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 overlay
Comment
SWPC Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
12119 2014.07.18 1 1 1 S21W67 0010 HRX HRX  
12120 2014.07.18
2014.07.20
      N17W86           plage
S3654 2014.07.20       N15W04           plage
S3655 2014.07.20       S17W31           plage
12121 2014.07.21
2014.07.22
9 35 18 N07E45 0210 CAO EKI beta-gamma

area: 0340

12122 2014.07.21
2014.07.22
3 7 3 S13E23 0020 CRO CRO

location: S12E25

S3661 2014.07.21       N23W57           plage
S3663 2014.07.22       N20W09           plage
12123 2014.07.22
2014.07.23
2 5 3 S14E39 0040 DAO DAO  
S3665 2014.07.22       N11W02         plage
S3667 2014.07.24   3 2 N09W14 0012   CRO    
S3668 2014.07.24   3 2 S09E44 0010   BXO    
S3669 2014.07.24   2   S12W17 0006   AXX    
Total spot count: 15 56 29  
Sunspot number: 55 126 79  (total spot count + 10 * number of spotted regions)
Weighted SN: 31 80 53  (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 44 44 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
2013.02 104.3 101.8 38.0 58.4 (-0.3) 6.11
2013.03 111.3 110.2 57.9 57.5 (-0.9) 10.56
2013.04 124.8 125.9 72.4 57.9 (+0.4) 5.40
2013.05 131.4 134.3 78.7 59.9 (+2.0) 9.73
2013.06 110.1 113.7 52.5 62.6 (+2.7) 12.60
2013.07 115.5 119.3 57.0 65.5 (+2.9) 9.47
2013.08 114.6 118.3 66.0 69.0 (+3.5) 8.27
2013.09 102.6 103.7 36.9 73.1 (+4.1) 5.23
2013.10  132.1 131.2 85.6 75.0 (+1.9) 7.71
2013.11  148.3 145.1 77.6 75.4 (+0.4) 5.68
2013.12 147.7 143.1 90.3 76.0 (+0.6) 4.68
2014.01 157.4 152.4 81.8 (78.2 projected, +2.2) 5.44
2014.02 170.3
(cycle peak)
166.3 102.3 (cycle peak) (79.7 projected, +1.5) 10.70
2014.03 149.9 148.5 91.9 (80.5 projected, +0.8) 4.88
2014.04 143.9 144.8 84.7 (79.7 projected, -0.8) 7.88
2014.05 129.7 132.9 75.2 (77.1 projected, -2.6) 5.75
2014.06 122.0 125.8 71.0 (74.5 projected, -2.6) 6.72
2014.07 138.8 (1)   87.3 (2A) / 112.8 (2B) / 83.2 (2C) (71.5 projected, -3.0) (4.3)

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.