Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 18, 2013 at 05:00 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 very quiet on June 17. Solar wind speed at SOHO ranged between 272 and 357 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 123.8 (decreasing 1.5 over the last solar rotation). The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.3). Three hour interval K indices: 11110011 (planetary), 12212111 (Boulder).

The background x-ray flux was at the class B6 level.

At midnight UTC the visible solar disk had 9 spotted active regions (in 2K resolution SDO images).

Region 11768 [S12W82] decayed slowly and quietly.
Region 11770 [S14E16] was quiet and stable.
Region 11771 [S13E31] was quiet and stable.
Region 11772 [S20E16] developed slowly and was mostly quiet.
Region 11773 [N03E38] developed slowly and quietly.
Region 11774 [S18E31] was mostly quiet and stable.
Region 11775 [S27E48] developed slowly and has a significant magnetic delta structure in the large penumbral structure. M flares are possible.

Spotted regions not numbered by SWPC:
New region S2485 [S24E28] emerged with penumbra spots.
New region S2486 [N13W13] emerged with a penumbra spot.

Coronal mass ejections (CMEs)

June 15-17: 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 northern hemisphere coronal hole (CH573) will be in a potentially geoeffective position on June 17-20.

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

Forecast

The geomagnetic field is expected to be quiet on June 18-20. A high speed stream associated with CH573 could start a disturbance late on June 20. Quiet to active conditions with a chance of minor storm intervals are possible on June 21-24.

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
11767 2013.06.07
2013.06.09
      S17W70           plage
S2468 2013.06.08       S32W47           plage
S2469 2013.06.09       N14W52         plage
11768 2013.06.11
2013.06.12
7 1 1 S12W85 0260 DKO HAX

area: 0040

11770 2013.06.12
2013.06.13
1 2 1 S14E15 0080 HSX HSX  
11769 2013.06.12
2013.06.13
      S23E11         merged with AR 11772
11772 2013.06.13
2013.06.14
17 29 15 S20E15 0100 DAI DAI area: 0130
11771 2013.06.13
2013.06.14
  1   S15E28 0002   AXX location: S13E31
S2478 2013.06.13       N07W32           plage
11773 2013.06.14
2013.06.15
13 43 15 N04E37 0090 DAI DAI area: 0160
11774 2013.06.14
2013.06.15
3 11 7 S18E31 0080 CSO DAO area: 0110
11775 2013.06.14
2013.06.15
9 26 12 S26E48 0380 DKO DKC beta-gamma-delta

area: 0520

S2482 2013.06.15       S19E52         plage
S2483 2013.06.15       S25W28         plage
S2484 2013.06.16       S34W23         plage
S2485 2013.06.17   2 1 S24E28 0005   AXX    
S2486 2013.06.17   1   N13W13 0002   AXX    
Total spot count: 50 116 52  
Sunspot number: 110 206 122  (total spot count + 10 * number of spotted regions)
Weighted SN: 90 151 87  (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): 66 72 67 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
2013.06 105.8 (1) 36.2 (2A) / 63.2 (2B) / 51.2 (2C) (59.0 projected, +0.3) (10.55)

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.