Solar Terrestrial Activity Report

Activity chart

Last major update issued on August 2, 2014 at 07:35 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 to unsettled on August 1. Solar wind speed at SOHO ranged between 285 and 420 km/s. A disturbance was observed arriving at ACE near 18h UTC, based on EPAM data the source of the disturbance was likely a CME.

Solar flux at 20h UTC on 2.8 GHz was 168 (decreasing 25.0 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 134.0. The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 7.8). Three hour interval K indices: 21122133 (planetary), 22133434 (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 16 active regions using 2K resolution (SN: 358) and 15 active regions using 1K resolution (SN: 255) SDO images on the visible solar disk.

Region 12121 [N07W65] decayed slowly and quietly.
Region 12125 [S14W08] decayed slowly and quietly.
Region 12126 [S09W69] decayed slowly and quietly.
Region 12127 [S07E08] gained spots, none of the trailing polarity spots have umbra. Further minor M class flares are possible.
Region 12128 [S21E08] was quiet and stable.
Region 12130 [S07E27] developed slightly and produced several flares. C and M class flaring is likely.
Region 12131 [S19E19] developed slowly and quietly.
Region 12132 [S19E45] developed quickly and could produce M class flares.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3680 [N13W23] was quiet and stable.
S3686 [N11W04] was quiet and stable.
S3691 [N09W69] was quiet and stable.
S3692 [N08W76] was quiet and stable.
New region S3695 [N18E75] rotated into view.
New region S3696 [S05E38] emerged with a few spots.
New region S3698 [N09E82] rotated partially into view.
New region S3700 [S07E18] emerged with a few spots.

C2+ Flares (GOES):

Magnitude Peak time (UTC) Location AR
C8.6 00:18 S17E60 12132
C4.8 11:43   filament eruption
M2.0 14:48   12130
M1.5 (LDE) 18:13   12127

A filament eruption across the central meridian and to the north of the equator was observed beginning at 10:28 UTC in SDO/AIA imagery. This event was associated with a partial halo CME which could reach Earth on August 4.

A weak halo CME was associated with the M1.5 flare in AR 12127. The CME could reach Earth on August 4.

Coronal mass ejections (CMEs)

August 1: A filament eruption in the northern hemisphere 10:30-13:00 UTC was associated with a partial halo CME. The CME could reach Earth on August 4. A weak halo CME was observed after an M1 flare in AR12127. The CME could reach Earth late on August 4.
July 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) was in 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 poor. Propagation on long distance northeast-southwest paths is poor to fair.

Forecast

The geomagnetic field is expected to be quiet to active on August 2-5 due to CME and coronal hole effects.

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
8 3 1 N08W69 0040 CAI BXO

location: N07W65

12122 2014.07.21
2014.07.22
      S13W89          

plage

location: S12W78

12123 2014.07.22
2014.07.23
      S14W66           plage
12126 2014.07.24
2014.07.26
8 8 5 S09W68 0070 CAO CSO

 

12124 2014.07.25
2014.07.26
      S21W19           plage
12125 2014.07.25
2014.07.26
1 10 4 S14W11 0020 HSX BXO location: S14W08
S3673 2014.07.26       S13W26         plage
12127 2014.07.27 11 43 20 S09E08 0240 DAC CAI

beta-gamma

location: S07E08

12128 2014.07.27 1 2 1 S21E07 0020 HSX HRX  
12129 2014.07.27
2014.07.28
2     S05W65 0010 BXO     plage
S3680 2014.07.28   5 1 N13W23 0010   BXO  
12130 2014.07.28
2014.07.29
22 36 23 S07E27 0260 EKC DAI beta-gamma
12131 2014.07.28
2014.07.29
6 22 14 S18E19 0030 CRO DRI area: 0080
S3683 2014.07.28       S16W40           plage
S3686 2014.07.29   9 3 N11W04 0020   BXO  
12132 2014.07.30
2014.07.31
16 33 20 S19E46 0200 DAC DKC beta-gamma

area: 0400

S3690 2014.07.30       N22E42           plage
S3691 2014.07.31   5 2 N09W69 0025   BXO  
S3692 2014.07.31   1   N08W76 0004   AXX  
S3693 2014.07.31       S16E57          
S3695 2014.08.01   1 1 N18E75 0030   HSX    
S3696 2014.08.01   9 3 S05E38 0050   DRO    
S3698 2014.08.01   5 3 N09E82 0080   DAO    
S3700 2014.08.01   6 4 S07E27 0020   DRO    
Total spot count: 75 198 105  
Sunspot number: 165 358 255  (total spot count + 10 * number of spotted regions)
Weighted SN: 115 245 152  (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): 99 125 140 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
2014.07 137.4 141.8 72.5 (69.9 projected, -3.0) 4.5
2014.08 168 (1)   5.3 (2A) / 165 (2B) / 83.9 (2C) (66.5 projected, -3.4) (7.8)

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). 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.