Solar Terrestrial Activity Report

Activity chart

Last major update issued on July 2, 2013 at 02:40 UTC. Irregular updates are likely until July 12.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update July 1, 2013)] [Cycle 24 progress (last update July 1, 2013) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update July 1, 2013)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update July 1, 2013)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update July 1, 2013)]

[POES auroral activity level since October 2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated June 30, 2013]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was quiet to unsettled on July 1. Solar wind speed at SOHO ranged between 451 and 562 km/s under the decreasing influence of a high speed stream from CH574.

Solar flux measured at 20h UTC on 2.8 GHz was 107.8 (decreasing 2.1 over the last solar rotation). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.1). Three hour interval K indices: 32221011 (planetary), 23332211 (Boulder).

The background x-ray flux was at the class B5 level.

At midnight UTC the visible solar disk had 13 spotted active regions (in 2K resolution SDO images).

Region 11777 [S17W77] was quiet and stable.
Region 11778 [S18W43] was quiet and stable.
Region 11780 [S11W61] decayed slowly and quietly.
Region 11781 [N22W45] decayed slowly and quietly.
Region 11783 [N08E48] was quiet and stable.
New region 11784 [S14E32] emerged on June 30 and was numbered by SWPC the next day.
New region 11785 [S10E78] rotated into view producing a few low level C flares.

Spotted regions not numbered by SWPC:
S2502 [S08W43] was quiet and stable.
New region S2518 [S32E31] emerged with a few spots.
New region S2519 [S17E44] emerged with a penumbra spot.
New region S2520 [S17E75] rotated into view.
New region S2521 [N11E34] emerged with a penumbra spot.
New region S2522 [S21E21] emerged with a penumbra spot.

The most interesting flare activity of the day was observed from a region just behind the northeast limb.

Coronal mass ejections (CMEs)

June 29 - July 1: 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

No obvious coronal holes are currently in or near Earth facing positions.

Coronal hole map

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet on July 2-5.

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: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% 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 STAR SDO SWPC STAR Current Previous
2K 1K
11777 2013.06.19
2013.06.20
1 1 1 S17W77 0090 HSX HSX  
11778 2013.06.22 3 5   S18W42 0010 BXO BXO  
S2498 2013.06.22       N15W31           plage
S2502 2013.06.24   2   S08W43 0004   BXO  
11779 2013.06.24
2013.06.25
      N17W28           plage
S2504 2013.06.24       N17W57           plage
11780 2013.06.25
2013.06.26
6 5 3 S12W60 0050 DSO CSO  
S2508 2013.06.26       N03W31           plage
11782 2013.06.27
2013.06.28
      S15E05         plage
S2510 2013.06.27       S11W09           plage
11781 2013.06.27
2013.06.28
16 25 13 N22W47 0140 DAI DRI area: 0090
S2512 2013.06.27       S39W58           plage
S2514 2013.06.28       S36W32           plage
11783 2013.06.29
2013.06.30
2 2 1 N05E45 0010 BXO HRX area: 0020

location: N08E48

11784 2013.06.30
2013.07.01
3 10 5 S15E32 0010 BXO DRO area: 0040
S2517 2013.06.30       N12W16         plage
11785 2013.07.01 1 7 3 S09E76 0110 HAX DKO   area: 0350

location: S10E78

S2518 2013.07.01   3 2 S32E31 0016   DRO    
S2519 2013.07.01   1 1 S17E44 0005   AXX    
S2520 2013.07.01   1   S17E75 0002   AXX    
S2521 2013.07.01   1 1 N11E34 0003   AXX    
S2522 2013.07.01   1   S21E21 0001   AXX    
Total spot count: 32 64 30  
Sunspot number: 102 194 120  (total spot count + 10 * number of spotted regions)
Weighted SN: 52 96 62  (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): 61 68 66 k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for STAR SDO 2K, k = 0.55 for STAR SDO 1K

Monthly solar cycle data

Month Average measured solar flux International sunspot number (SIDC) Smoothed sunspot number Average ap
(3)
2011.11 153.5 (cycle peak) 96.7 (cycle peak) 61.1 (+1.2) 5.55
2012.02 106.5 32.9 66.9 (+1.4)
possible cycle 24 max
8.81
2012.04 113.0 55.2 64.6 (-2.2) 10.10
2012.05 121.5 69.0 61.7 (-2.9) 7.06
2012.06 119.6 64.5 58.9 (-2.8) 10.08
2012.07 133.9 66.5 57.7 (-1.2) 13.90
2012.08 115.4 63.0 58.1 (+0.4) 7.96
2012.09 122.9 61.4 58.1 (-0.0) 8.07
2012.10 123.3 53.3 58.6 (+0.5) 9.97
2012.11 121.3 61.8 59.7 (+1.1) 7.08
2012.12 108.6 40.8 59.6 (-0.1) 3.44
2013.01 127.1 62.9 (58.7 projected, -0.9) 4.69
2013.02 104.3 38.0 (58.3 projected, -0.4) 6.11
2013.03 111.3 57.9 (57.9 projected, -0.4) 10.56
2013.04 124.8 72.4 (57.5 projected, -0.4) 5.40
2013.05 131.4 78.7 (57.6 projected, +0.1) 9.73
2013.06 110.1 52.5 (57.9 projected, +0.3) 12.06
2013.07 107.8 (1) 3.3 (2A) / 102 (2B) / 51.4 (2C) (58.0 projected, +0.1) (6.1)

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 SIDC 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 Potsdam WDC ap indices.

This report has been prepared by Jan Alvestad. It is based on 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.