Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 12, 2013 at 04:20 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 unsettled on June 11. Solar wind speed at SOHO ranged between 346 and 440 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 89.5 (decreasing 56.1 over the last solar rotation). The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 5.3). Three hour interval K indices: 00113212 (planetary), 10113322 (Boulder).

The background x-ray flux was at the class B1 level.

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

Region 11765 [N08W68] decayed quickly and quietly.
Region 11767 [S17E27] lost the leader spot and gained a trailing penumbra spot.

Spotted regions not numbered by SWPC:
S2468 [S33E29] reemerged with penubmra spots.
S2469 [N13E18] was quiet and stable.
New region S2472 [S11W06] emerged with several spots.
New region S2473 [S13W02] emerged near S2472 with penumbra spots.

Coronal mass ejections (CMEs)

June 9-11: 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 to fair.

Forecast

The geomagnetic field is expected to be quiet on June 12-15.

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
S2459 2013.06.03       S24W53           plage
11765 2013.06.03
2013.06.05
4 4 1 N09W64 0050 DAO CSO

location: N08W68

S2461 2013.06.04       N15W58           plage
S2463 2013.06.06       N07W16         plage
S2464 2013.06.07       N25W27           plage
11767 2013.06.07
2013.06.09
  1   S17E14 0003   AXX  
S2467 2013.06.07       S12W19           plage
S2468 2013.06.08   2 1 S33E29 0005   AXX    
S2469 2013.06.09   7   N13E18 0015   BXO images/AR_S2469_20130611_2345.jpg  
S2470 2013.06.09       S24W08           plage
S2471 2013.06.09       S13W44           plage
S2472 2013.06.11   7 3 S11W06 0050   DRO    
S2473 2013.06.11   3 1 S13W02 0008   BXO    
Total spot count: 4 24 6  
Sunspot number: 14 84 46  (total spot count + 10 * number of spotted regions)
Weighted SN: 9 32 14  (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): 8 29 25 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
2012.03 114.7 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) 9.73
2013.06 104.4 (1) 20.8 (2A) / 56.8 (2B) / 59.2 (2C) (59.0 projected, +0.3) (14.56)

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.