Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 8, 2013 at 04:35 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update June 1, 2013)] [Cycle 24 progress (last update June 1, 2013) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update June 1, 2013)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update June 1, 2013)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update June 6, 2013)]

[POES auroral activity level since October 2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated May 12, 2013]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was quiet to major storm on June 7. Solar wind speed at SOHO ranged between 357 and 506 km/s. The passage of a magnetic cloud caused active to major storm conditions during the first half of the day. Early on June 8 a weak disturbance related to CH572 appears to be in progress.

Solar flux measured at 20h UTC on 2.8 GHz was 109.8 (decreasing 26.8 over the last solar rotation). The Potsdam WDC planetary A index was 26 (STAR Ap - based on the mean of three hour interval ap indices: 25.5). Three hour interval K indices: 56543222 (planetary), 57653322 (Boulder).

The background x-ray flux was at the class B2 level.

At midnight UTC the visible solar disk had 6 spotted active regions (in 2K resolution SDO images).

Region 11762 [S31W82] decayed slowly as it rotated to the southwest limb. C5+ flare: major M5.9 long duration event peaking at 22:49 UTC.
Region 11765 [N08E10] matured and was mostly quiet. C flares are possible.

Spotted regions not numbered by SWPC:
New region S2464 [N25E25] emerged with penumbra spots.
New region S2465 [S03W20] emerged with a penumbra spot.
New region S2466 [S17E69] emerged near the southeast limb.
New region S2467 [S12E31] emerged with penumbra spots in an old plage area.

Coronal mass ejections (CMEs)

June 5-7: 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 coronal hole (CH572) in the southern hemisphere was in an Earth facing position on June 4-5.

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 good.

Forecast

The geomagnetic field is expected to be quiet to unsettled with a chance of active intervals on June 8-9 due to effects from CH572. Quiet conditions are likely on June 10-11.

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
11758 2013.05.26       S21W85         location: S14W80

plage

11761 2013.05.28
2013.05.29
      S17W72           plage
11764 2013.05.28
2013.06.02
2     N14W88 0060 HSX     rotated out of view
11760 2013.05.29       N12W58          

plage

11766 2013.05.29
2013.06.05
1     N19W71 0010 AXX     spotless
11762 2013.06.01 16 2 2 S28W87 0200 DAI DAO

area: 0130

location: S31W82

11763 2013.06.01       S14W80           see AR 11758
S2457 2013.06.02       N18W35           plage
S2459 2013.06.03       S24W01           plage
11765 2013.06.03
2013.06.05
17 22 11 N08W10 0190 DAI DSO

area: 0300

S2461 2013.06.04       N15W06           plage
S2462 2013.06.05       N00W48           plage
S2463 2013.06.06       N13E41         plage
S2464 2013.06.07   2   N25E25 0004   AXX    
S2465 2013.06.07   1 1 S03W20 0003   AXX    
S2466 2013.06.07   1   S17E69 0002   AXX    
S2467 2013.06.07   2   S12E31 0003   AXX    
Total spot count: 36 30 14  
Sunspot number: 76 90 44  (total spot count + 10 * number of spotted regions)
Weighted SN: 56 40 24  (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): 46 32 24 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 max) 96.7 (cycle max) 61.1 (+1.2) 5.55
2012.02 106.5 32.9 66.9 (+1.4)
possible cycle 24 max
8.81
2012.03 114.7 64.3 66.8 (-0.1) 16.08
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 (59.5 projected, -0.2) 3.44
2013.01 127.1 62.9 (59.1 projected, -0.4) 4.69
2013.02 104.3 38.0 (59.3 projected, +0.2) 6.11
2013.03 111.3 57.9 (58.9 projected, -0.4) 10.56
2013.04 124.8 72.4 (58.6 projected, -0.3) 5.40
2013.05 131.4 78.7 (58.7 projected, +0.1) 9.04
2013.06 109.4 (1) 17.4 (2A) / 74.6 (2B) / 67.0 (2C) (59.0 projected, +0.3) (18.88)

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.