Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 1, 2014 at 05:05 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update August 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 August 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update August 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 31. Solar wind speed at SOHO ranged between 275 and 302 km/s.

Solar flux at 20h UTC on 2.8 GHz was 156 (decreasing 31.6 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 133.6. 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: 11111112 (planetary), 11122312 (Boulder).

The background x-ray flux is at the class B9 level.

At the time of counting spots (see image time), spots were observed in 15 active regions using 2K resolution (SN: 312) and 14 active regions using 1K resolution (SN: 218) SDO images on the visible solar disk.

Region 12121 [N07W52] decayed quietly.
Region 12125 [S14E04] decayed slowly and quietly.
Region 12126 [S10W57] decayed quickly and was quiet.
Region 12127 [S08E21] decayed slowly and was mostly quiet.
Region 12128 [S21E22] was quiet and stable.
Region 12129 [S05W49] decayed slowly and quietly.
Region 12130 [S08E42] was fairly active during the day. The region decayed losing all trailing poalrity umbrae.
Region 12131 [S19E33] developed slowly and quietly.
New region 12132 [S19E60] emerged on July 30 and developed quickly on July 31 when the region was numbered by SWPC.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3673 [S13W13] reemerged with penumbra spots.
S3680 [N12W12] was quiet and stable.
S3686 [N12E10] was quiet and stable.
New region S3691 [N09W55] emerged with a few spots to the northwest of AR 12121.
New region S3692 [N09W63] emerged to the west of AR 12121.
New region S3693 [S16E70] rotated into view.

C2+ Flares (GOES):

Magnitude Peak time (UTC) Location AR
M2.5 11:14   12130
C3.5 15:17 S09E49 12130
C2.4 21:17    

Coronal mass ejections (CMEs)

July 29, 31: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
July 30: A filament eruption in the northeast quadrant after 05h UTC was associated with a partial halo CME. This CME could reach Earth on August 2.

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 (CH629) will likely rotate into an Earth facing position on July 31-August 1.

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 fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet on August 1. A CME could cause unsettled and active intervals on August 2. Weak effects from CH629 could cause a few unsettled intervals on August 3-4.

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
12121 2014.07.21
2014.07.22
11 10 4 N08W54 0090 CAI CAO

location: N07W52

12122 2014.07.21
2014.07.22
      S13W75          

plage

location: S12W65

12123 2014.07.22
2014.07.23
      S14W52           plage
12126 2014.07.24
2014.07.26
7 12 5 S10W57 0100 DAO CAO

 

12124 2014.07.25
2014.07.26
      S21W05         plage
12125 2014.07.25
2014.07.26
1 10 7 S14E03 0020 HSX CRO  
S3673 2014.07.26   2 2 S13W13          
12127 2014.07.27 10 27 10 S09E22 0270 DKC DAO

beta-gamma

12128 2014.07.27 1 4 3 S20E21 0030 HSX HRX  
12129 2014.07.27
2014.07.28
  2   S05W51 0004   BXO  
S3680 2014.07.28   9 3 N12W12 0013   BXO  
12130 2014.07.28
2014.07.29
19 37 17 S07E42 0290 DKC CSI beta-gamma
12131 2014.07.28
2014.07.29
5 16 11 S18E33 0030 DRO DRI area: 0070
S3683 2014.07.28       S16W27           plage
S3685 2014.07.29       S19W57           plage
S3686 2014.07.29   7 1 N12E10 0010   BXO  
S3687 2014.07.29       N16W48           plage
12132 2014.07.30
2014.07.31
5 15 9 S18E60 0030 CRO DAC beta-gamma

area: 0150

S3690 2014.07.30       N22E55         plage
S3691 2014.07.31   8 4 N09W55 0050   CRO    
S3692 2014.07.31   2 1 N09W63 0010   CRO    
S3693 2014.07.31   1 1 S16E70 0003   AXX    
Total spot count: 59 162 78  
Sunspot number: 139 312 218  (total spot count + 10 * number of spotted regions)
Weighted SN: 105 202 118  (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): 83 109 120 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
2013.04 124.8 125.9 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 77.3 (+1.3) 5.44
2014.02 170.3
(cycle peak)
166.3 102.3 (cycle peak) (78.1 projected, +0.8) 10.70
2014.03 149.9 148.5 91.9 (79.0 projected, +0.9) 4.88
2014.04 143.9 144.8 84.7 (78.1 projected, -0.9) 7.88
2014.05 129.7 132.9 75.2 (75.6 projected, -2.5) 5.75
2014.06 122.0 125.8 71.0 (72.9 projected, -2.7) 6.72
2014.07 137.4   72.5 (69.9 projected, -3.0) 4.5
2014.08 (1)   (2A/2B) / 83.8 (2C) (66.5 projected, -3.4) ()

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). 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.