Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 6, 2013 at 04:10 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 on June 5. Solar wind speed at SOHO ranged between 450 and 569 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 108.8 (decreasing 19.6 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: 5.0). Three hour interval K indices: 21112121 (planetary), 32122222 (Boulder).

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

At midnight UTC the visible solar disk had 7 spotted active regions (in 2K resolution SDO images).

Region 11758 [S14W53] decayed and could soon become spotless.
Region 11762 [S29W57] lost some penumbral area but still has a magnetic delta structure within the southermost trailing penumbra. Another M class flare is possible. C5+ flare: M1.3/1F long duration event peaking at 08:57 UTC. This event was associated with a CME, however, the CME doesn't appear to have any Earth directed components.
Region 11764 [N13W64] decayed slowly and quietly.
New region 11765 [N09E19] emerged on June 3 and was numbered by SWPC 2 days later. The region developed significantly on June 5.
New region 11766 [N19W43] emerged on May 29, had a few spotless days, then reemerged on June 4 and was numbered the next day by SWPC. Slow development was observed on June 5.

Spotted regions not numbered by SWPC:
S2457 [N18W09] was quiet and stable.
New region S2462 [N00W22] emerged with penumbra spots.

Coronal mass ejections (CMEs)

June 3-5: 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 fair.

Forecast

The geomagnetic field is expected to be quiet to unsettled on June 6. Quiet to active conditions are possible on June 7-8 due to effects from CH572.

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
11757 2013.05.24
2013.05.25
      S06W78           plage
11758 2013.05.26   5   S21W58 0010   BXO location: S14W53
11759 2013.05.26
2013.05.27
      S07W64           plage
11761 2013.05.28
2013.05.29
      S17W44           plage
11764 2013.05.28
2013.06.02
4 9 3 N12W62 0090 DAO DAO location: N13W64
11760 2013.05.29       N12W31        

plage

11766 2013.05.29
2013.06.05
4 5 3 N18W43 0010 BXO DRO area: 0050
S2452 2013.05.29       N20W54           plage
11762 2013.06.01 16 18 11 S30W60 0540 EKO EAC beta-gamma-delta

area: 0400

location: S29W57

11763 2013.06.01 2     S14W52 0010 HSX       see AR 11758
S2456 2013.06.01       N28W57           plage
S2457 2013.06.02   1   N18W09 0003   AXX  
S2458 2013.06.02       S08W39           plage
S2459 2013.06.03       S24E25         plage
11765 2013.06.03
2013.06.05
5 19 10 N09E17 0030 CRO DAI area: 0130
S2461 2013.06.04       N15E20         plage
S2462 2013.06.05   2   N00W22 0003   BXO    
Total spot count: 31 59 27  
Sunspot number: 81 129 67  (total spot count + 10 * number of spotted regions)
Weighted SN: 54 77 45  (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): 48 45 37 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) 12.5 (2A) / 75.0 (2B) / 70.5 (2C) (59.0 projected, +0.3) (17.7)

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.