Solar Terrestrial Activity Report

Activity chart

Last major update issued on June 16, 2013 at 05:45 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 15. Solar wind speed at SOHO ranged between 277 and 358 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 110.0 (decreasing 25.3 over the last solar rotation). The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.9). Three hour interval K indices: 21110101 (planetary), 21112211 (Boulder).

The background x-ray flux was at the class B3 level.

At midnight UTC the visible solar disk had 12 spotted active regions (in 2K resolution SDO images).

Region 11768 [S13W59] was quiet and stable.
Region 11769 [S23E37] was quiet and stable.
Region 11770 [S14E43] was quiet and stable.
Region 11771 [S12E52] decayed quietly.
Region 11772 [S21E42] gained spots and was quiet.
New region 11773 [N04E65] rotated into view on June 14 and got its NOAA number the next day.
New region 11774 [S14E59] rotated into view on June 14 and developed slowly on June 15 when it was numbered by SWPC. C class flaring is possible.
New region 11775 [S27E76] rotated partly into view on June 14, C flares are possible.

Spotted regions not numbered by SWPC:
S2468 [S32W21] reemerged with penumbra spots.
S2469 [N13W38] was quiet and stable.
New region S2482 [S18E80] rotated into view. While there are several spots at 4K resolution, only one was observable at 2K.
New region S2483 [S24W02] emerged with a penumbra spot.

Coronal mass ejections (CMEs)

June 13-15: 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) could rotate into a potentially geoeffective position on June 18-19.

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 16-19.

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
      S17W42           plage
S2468 2013.06.08   3   S32W21 0005   AXX    
S2469 2013.06.09   6 1 N13W35 0010   BXO images/AR_S2469_20130615_2345.jpg images/AR_S2469_20130614_2345.jpg  
11768 2013.06.11
2013.06.12
6 14 6 S11W59 0270 DKO DKO

area: 0400

location: S13W59

S2473 2013.06.11       S13W54           plage
11770 2013.06.12
2013.06.13
1 2 1 S14E41 0060 HSX HSX area: 0100

location: S14E43

11769 2013.06.12
2013.06.13
2 3 2 S22E35 0020 CRO CRO location: S23E37
11772 2013.06.13
2013.06.14
8 24 13 S20E40 0030 CRI CRI area: 0090

location: S21E42

11771 2013.06.13
2013.06.14
1 3 1 S11E51 0010 AXX AXX  
S2478 2013.06.13       N07W06           plage
11773 2013.06.14
2013.06.15
1 5 2 N04E64 0030 HRX CAO area: 0050
11774 2013.06.14
2013.06.15
1 6 3 S18E58 0030 BXO DAO location: S19E59
11775 2013.06.14
2013.06.15
1 6 2 S25E74 0060 HAX CAO beta-gamma

location: S27E76

area: 0250

S2482 2013.06.15   1   S18E80 0006   AXX    
S2483 2013.06.15   1 1 S24W02 0004   AXX    
Total spot count: 21 74 32  
Sunspot number: 101 194 132  (total spot count + 10 * number of spotted regions)
Weighted SN: 50 110 68  (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): 61 68 73 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
2013.06 104.0 (1) 29.0 (2A) / 58.1 (2B) / 52.7 (2C) (59.0 projected, +0.3) (11.56)

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.