Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 12, 2012 at 04:25 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-24 (last update June 2, 2012)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update June 2, 2012)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update June 2, 2012)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update May 3, 2012)]

[POES auroral activity level since October 2009 - updated June 10, 2012]
[Solar polar fields vs solar cycles - updated June 27, 2011]

Recent activity

The geomagnetic field was quiet to minor storm on June 11. Solar wind speed at SOHO ranged between 353 and 441 km/s. While the total field of the interplanetary magnetic field was only at slightly elevated levels, Bz was nearly fully southwards all day and caused a geomagnetic disturbance.

Solar flux measured at 20h UTC on 2.8 GHz was 133.9 (increasing 4.9 over the last solar rotation). The Potsdam WDC planetary A index was 18 (STAR Ap - based on the mean of three hour interval ap indices: 18.1). Three hour interval K indices: 22322345 (planetary), 22422324 (Boulder).

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

At midnight UTC the visible solar disk had 10 spotted active regions (in 2K resolution SDO images).

Region 11494 [S17W74] was quiet and stable.
Region 11499 [N14W60] decayed slowly and quietly.
Region 11504 [S17E41] developed adding spots and penumbral area. The region is fairly compact and may be capable of producing M flares.
Region 11505 [S09E39] developed slowly and quietly.
Region 11506 [N11E52] developed slowly and currently has a weak magnetic delta structure in the expanding large penumbra. An M class flare is possible.
Region 11507 [S26E17] developed slowly and produced a number of small C flares.

Spotted active regions not numbered or interpreted differently by NOAA/SWPC:
S1719
[S26E32] decayed slowly and was quiet.
S1724 [N18W82] was quiet and stable.
S1726 [S15E24] developed slowly and quietly.
S1728 [N08W24] was quiet and stable.

Coronal mass ejections (CMEs)

June 9-11: No obviously Earth directed CMEs were observed in LASCO or 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 potentially geoeffective positions. 

Coronal hole map

The above coronal hole map is based on a method where coronal holes are detected automatically. While the method may need some fine tuning, it has significant advantages over detecting coronal holes manually. The main improvement is the ability to detect coronal holes at and just beyond the solar limbs. Early results using this method for SDO images over a span of several weeks indicate a good match between coronal holes observed over the visible disk and their extent and position at the east and west limbs. Note that the polar coronal holes are easily detected using this method, the extent and intensity of both CHs are consistent with other data sources.

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 major storm on June 12 and mostly quiet on June 13-14.

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 higher resolution image) Compare to the previous day's image

When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue (blue-green) 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
11494 2012.05.30
2012.05.31
1 1 1 S17W74 0080 HAX HSX

area: 0180

11496 2012.05.30
2012.06.01
      N17W76        

plage

11498 2012.05.31
2012.06.01
      N07W67           plage
11499 2012.06.01
2012.06.03
5 9 4 N16W60 0010 BXO BXO  
11502 2012.06.02
2012.06.04
      S17W58           plage

location: S16W52

S1709 2012.06.04       N13W41           plage
S1713 2012.06.06       N11W33           plage
11507 2012.06.07
2012.06.10
10 37 22 S26E17 0030 CAO DAI beta-gamma

area: 0100

11504 2012.06.08
2012.06.09
15 34 21 S17E40 0080 ERI EAC

area: 0450

SWPC classification and area don't reflect reality

S1717 2012.06.08       S15W36           plage
S1718 2012.06.08       N34W42           plage
11505 2012.06.09 5 20 8 S09E37 0040 CAO DSI location: S09E39

area: 0200

S1719 2012.06.09   2   S26E32 0000   BXO  
11506 2012.06.09
2012.06.10
2 15 8 N11E52 0050 CAO DKO beta-delta

area: 0270

S1721 2012.06.09       N10E20           plage
S1722 2012.06.09       S17W34           plage
S1723 2012.06.09       S30E06         plage
S1724 2012.06.10   1   N18W82 0000   AXX  
S1725 2012.06.10       S25W58         plage
S1726 2012.06.10   6 3 S15E24 0010   BXO  
S1727 2012.06.10       N10W19         plage
S1728 2012.06.10   2 1 N08W24 0000   BXO  
Total spot count: 38 127 68  
Sunspot number: 98 227 148  (total spot count + 10 * number of spotted regions)
Weighted penumbral SN: 61 157 98  (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): 59 79 81 k * (sunspot number). k = 0.6 for SWPC, k = 0.35 (changed from 0.45 on March 1, 2011) 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)
2008.07 65.7 (SF minimum) 0.5 2.8 (-0.4)  
2008.12 69.2 0.8 1.7 (-)
sunspot minimum
 
2011.03 115.0 56.2 36.9 (+3.5) 8.18
2011.04 112.6 54.4 41.8 (+4.9) 8.83
2011.05 95.8 41.6 47.6 (+5.8) 8.94
2011.06 95.8 37.0 53.2 (+5.6) 8.06
2011.07 94.2 43.9 57.2 (+4.0) 8.16
2011.08 101.7 50.6 59.0 (+1.8) 7.26
2011.09 133.8 78.0 59.5 (+0.5) 12.27
2011.10 137.3 88.0 59.9 (+0.4) 8.28
2011.11 153.5 96.7 61.1 (+1.2) 5.55
2011.12 141.3 73.0 (64.3 projected, +3.2) 3.78
2012.01 132.5 58.3 (68.0 projected, +3.7) 7.15
2012.02 106.5 33.1 (71.3 projected, +3.3) 8.81
2012.03 114.7 64.2 (73.0 projected, +1.7) 16.08
2012.04 113.0 55.2 (73.2 projected, +0.2) 10.10
2012.05 121.5 69.0 (73.2 projected, +0.0) 8.75
2012.06 130.0 (1) 44.8 (2A) / 122.1 (2B) (73.9 projected, +0.7) (13.52)

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) Month average to date.
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.