Solar Terrestrial Activity Report

Last major update issued on June 23, 2011 at 04:40 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-24 (last update June 1, 2011)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update June 1, 2011)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update June 1, 2011)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update June 1, 2011)]

[POES auroral activity level charts since October 2009 - updated June 20, 2011]
Annotated geomagnetic activity charts - Carrington rotation 2109 [April-May 2011] - 2110 [May-June 2011] NEW
[Solar polar fields vs solar cycles - updated June 11, 2011]

Recent activity

The geomagnetic field was quiet to active on June 22. Solar wind speed ranged between 423 and 643 km/s. A high speed stream from CH457 became the dominant solar wind source after noon. There was a sudden change in solar wind parameters at SOHO at 02:18 UTC on June 23, maybe the arrival of the CME observed on June 21

Solar flux measured at 20h UTC on 2.8 GHz was 92.9 (increasing 10.2 over the last solar rotation). The planetary A index was 12 (STAR Ap - based on the mean of three hour interval ap indices: 11.9). Three hour interval K indices: 32122343 (planetary), 22222333 (Boulder).

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

At midnight UTC the visible solar disk had 6 spotted regions.

Region 11236 decayed slowly and quietly.
Region 11237 was quiet and stable.
Region 11239 was quiet and stable.
Region 11240 developed slowly and was quiet.

Spotted regions not numbered by NOAA/SWPC:
[S1077] emerged in the northeast quadrant on June 22. Location at midnight: N18E23
[S1078] emerged at a high latitude in the southwest quadrant on June 22. Polarities are reversed. Location at midnight: S47W12

Coronal mass ejections (CMEs)

June 20 and 22: No obviously earth directed CMEs were observed.
June 21: A halo CME was observed after a C7 LDE in region 11236. Although most of the core of the CME was observed over the northern limbs, Earth appears to be in the path of the southern part of the core. The CME will likely reach Earth on June 23.

Coronal holes

Coronal hole history (since late October 2002)
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago

A recurrent coronal hole (CH457) in the southern hemisphere was Earth facing on June 19-20. A coronal hole (CH459) in the northern hemisphere will be Earth facing on June 23.

The above coronal hole map is based on a new method where coronal holes are detected automatically. The method may need some fine tuning, however, 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 the new method, the extent and intensity of both holes 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 unsettled to minor storm on June 23-24 due to effects from CH457 and CME effects. Quiet to unsettled is likely on June 25.

Coronal holes (1) Coronal mass ejections (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 polarity overlay
Comment
SWPC STAR SDO SWPC STAR Current Previous
11236 2011.06.13
2011.06.14
6 13 N16W32 0140 CSO CHO

area: 0260

location: N17W37

11237 2011.06.16
2011.06.17
  6 S18W01 0000   BXO location: S18E02
11239 2011.06.17
2011.06.20
3 6 N18W14 0010 BXO BXO

location: N17W13

11238 2011.06.18
2011.06.19
    S17W31           plage
S1072 2011.06.18     S18W42           plage
S1073 2011.06.19     S05E04           plage
S1074 2011.06.19     S16W49           plage
11240 2011.06.20 5 11 S19E16 0010 BXO CRI location: S20E15

area: 0030

S1075 2011.06.20     N36W11           plage
S1076 2011.06.21     S09E23         reversed polarities

plage

S1077 2011.06.22   4 N18E23 0000   BXO    
S1078 2011.06.22   1 S47W12 0000   AXX   reversed polarities
Total spot count: 14 41  
Sunspot number: 44 101  

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
3.25
2010.02 84.7 18.8 10.6 (+1.3) 4.15 / 4.61
2010.03 83.4 15.4 12.3 (+1.7) 4.58 / 4.65
2010.04 75.9 8.0 14.0 (+1.7) 10.22 / 10.24
2010.05 73.8 8.7 15.5 (+1.5) 9.18 / 8.15
2010.06 72.5 13.6 16.4 (+0.9) 8.17 / 6.85
2010.07 79.8 16.1 16.7 (+0.3) 6.31 / 5.15
2010.08 79.2 19.6 17.4 (+0.7) 8.49 / 7.77
2010.09 81.1 25.2 19.6 (+2.2) 5.33 / 5.45
2010.10 81.6 23.5 23.2 (+3.6) 6.07 / 6.27
2010.11 82.5 21.5 26.5 (+3.3) 4.80 / 5.50
2010.12 84.2 14.4 (29.4 predicted, +2.9) 3.41 / 4.35
2011.01 83.6 19.1 (32.6 predicted, +3.2) 4.32 / 5.51
2011.02 94.6 29.4 (35.2 predicted, +2.6) 5.41 / 6.44
2011.03 115.0 56.2 (37.5 predicted, +2.3) 7.79
2011.04 112.6 54.4 (40.4 predicted, +2.9) 9.71
2011.05 95.8 41.6 (43.7 predicted, +3.3) 9.18
2011.06 97.5 (1) 44.7 (2A) / 60.9 (2B) (47.4 predicted, +3.7) (9.55)

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) Month average to date.
3) Running average based on the preliminary daily SWPC ap indices. Values in red are based on the official NGDC 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.