Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 9, 2012 at 07:05 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 2, 2012]
[Solar polar fields vs solar cycles - updated June 27, 2011]

Recent activity

The geomagnetic field was quiet to unsettled on June 8. Solar wind speed at SOHO ranged between 490 and 594 km/s under the decreasing influence of a high speed stream from CH520.

Solar flux measured at 20h UTC on 2.8 GHz was 124.2 (decreasing 5.3 over the last solar rotation). The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 7.6). Three hour interval K indices: 22331121 (planetary), 12342221 (Boulder).

The background x-ray flux is at the class B4 level.

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

Region 11493 [N14W49] was motly quiet and stable. AR S1703 merged with this region.
Region 11494 [S16W32] decayed slowly after a C7.7 flare at 03:07 UTC.
Region 11497 [S21W58] decayed fairly quickly and was quiet.
Region 11498 [N08W24] was quiet and stable.
Region 11499 [N15W23] lost some spots, rudimentary penumbra developed on the trailing spots.

Spotted active regions not numbered or interpreted differently by NOAA/SWPC:
S1715
[S25E53] was quiet and stable.
New region S1716 [S17E80] rotated into view at the southeast limb.
New region S1717 [S15E03] emerged with a tiny spot.
New region S1718 [N34W03] emerged with a single spot.

Coronal mass ejections (CMEs)

June 6: A partial halo CME associated with an M2 flare in AR 11494 was observed from 20:39 UTC in LASCO images. This CME could reach Earth late on June 9 or early on June 10.
June 7-8: 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 about to rotate into 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 fair.

Forecast

The geomagnetic field is expected to be quiet on June 9. The CME observed on June 6 could reach Earth late on June 9 or early on June 10 and cause unsettled to active conditions with a chance of minor storming. Quiet conditions are likely on June 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 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
5 13 5 S18W33 0120 CAO CHO beta-gamma

area: 0290

11493 2012.05.30
2012.05.31
4 9 6 N14W47 0070 CAO CSO

beta-gamma

location: N14W49

area: 0180

11496 2012.05.30
2012.06.01
1     N17W36 0010 AXX      

merged with AR 11499

11497 2012.05.30
2012.06.01
5 9 6 S22W58 0070 DAO DAO

 

11498 2012.05.31
2012.06.01
1 10 4 N08W24 0010 CAO CRO  
S1703 2012.06.01       N13W41         merged with AR 11493
11499 2012.06.01
2012.06.03
14 28 16 N15W23 0020 CAO FRI  
11502 2012.06.02
2012.06.04
      S17W16           plage
11501 2012.06.04       N07W45           plage
S1709 2012.06.04       N13W02           plage
11503 2012.06.04
2012.06.05
      N09W83           plage
S1713 2012.06.06       N11E06         plage
S1714 2012.06.06       N27W75         plage
S1715 2012.06.07   1 1 S25E53 0000   AXX  
S1716 2012.06.08   5 2 S17E80 0050   DSO    
S1717 2012.06.08   1   S15E03 0000   AXX    
S1718 2012.06.08   1   N34W03 0000   AXX    
Total spot count: 30 77 40  
Sunspot number: 90 167 110  (total spot count + 10 * number of spotted regions)
Weighted penumbral SN: 55 108 71  (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): 54 58 61 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
2012.06 129.9 (1) 34.2 (2A) / 128.1 (2B) (73.9 projected, +0.7) (14.50)

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.