Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 24, 2014 at 06:55 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 23. Solar wind speed at SOHO ranged between 286 and 334 km/s.

Solar flux at 20h UTC on 2.8 GHz was 99.1 (decreasing 0.9 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 133.0. The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.9). Three hour interval K indices: 01000122 (planetary), 00101333 (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 5 active regions using 2K resolution (SN: 92) and 4 active regions using 1K resolution (SN: 64) SDO images on the visible solar disk.

Region 12119 [S21W53] decayed slowly and quietly.
Region 12121 [N07E57] gained a few spots and was quiet.
Region 12122 [S12E38] was quiet and stable.
New region 12123 [S13E54] emerged on July 22 and was numbered the next day by SWPC.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3665 [N11E11] decayed slowly and quietly.

C2+ Flares (GOES):

Magnitude Peak time (UTC) Location AR
       

Coronal mass ejections (CMEs)

July 21-23: 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 (CH627) rotated into an Earth facing position on July 20-21. A recurrent trans equatorial coronal hole (CH628) rotate 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 24-27. On July 24-25 there's a chance of a few unsettled intervals should a stream from CH627 reach Earth. Unsettled intervals are possible on July 28 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 3 3 1 S20W53 0020 CSO CAO  
12120 2014.07.18
2014.07.20
      N17W72           plage
S3654 2014.07.20       N15E09           plage
S3655 2014.07.20       S17W18         plage
S3656 2014.07.20       S07W58           plage
12121 2014.07.21
2014.07.22
5 22 14 N06E57 0120 DAI EAO beta-gamma

area: 0320

12122 2014.07.21
2014.07.22
5 11 7 S15E34 0020 CRO DRO

area: 0050

location: S12E38

S3660 2014.07.21       N00W39           plage
S3661 2014.07.21       N23W44           plage
S3663 2014.07.22       N20E04         plage
12123 2014.07.22
2014.07.23
2 3 2 S13E51 0020 CRO DAO area: 0070
S3665 2014.07.22   3   N11E11 0004   AXX  
Total spot count: 15 42 24  
Sunspot number: 55 92 64  (total spot count + 10 * number of spotted regions)
Weighted SN: 31 60 42  (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 32 35 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
2014.07 140.4 (1)   85.5 (2A) / 115.3 (2B) / 82.8 (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.