Solar Terrestrial Activity Report

Activity chart

Last major update issued on January 13, 2013 at 06:50 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update January 1, 2013)] [Cycle 24 progress (last update January 1, 2013) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update January 1, 2013)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update January 1, 2013)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update January 2, 2013)]

[POES auroral activity level since October 2009 - updated October 7, 2012]
[Solar polar fields vs solar cycles - updated January 8, 2013]

Recent activity

The geomagnetic field was quiet on January 12. Solar wind speed at SOHO ranged between 323 and 391 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 168.5 (increasing 49.4 over the last solar rotation). The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 2.9). Three hour interval K indices: 21010011 (planetary), 11011110 (Boulder).

The background x-ray flux was at the class B7 level.

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

Region 11642 [S25W81] was quiet and stable.
Region 11644 [N13W70] decayed slowly and quietly.
Region 11649 [S15W32] was quiet and stable.
Region 11650 [S30W27] was quiet and stable.
Region 11652 [N19W16] decayed slowly and became more active producing several C flares and, early on Janaury 13, an M1 flare.
Region 11654 [N07E19] lost penumbral area in the leader spots. The trailer spot has become the largest penumbral area in the region. The magnetic detla structure from the previous day disappeared, instead a stronger delta formed in the southeastern part of the intermediate spot section. M flares are possible. C5+ flares: C5.3 at 02:24 UTC.
Region 11655 [S20W37] decayed slowly and quietly.
Region 11656 [N22E42] was quiet and stable

Spotted regions not numbered by SWPC:
S2167 [S33E03] was quiet and stable.
New region S2172 [S12E77] rotated into view.

Coronal mass ejections (CMEs)

January 10-12: 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

No obvious coronal holes are currently in or near Earth facing 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 good. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet on January 13-15.

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 (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
11642 2012.12.30
2012.12.31
1 1 1 S25W84 0110 HSX HSX

location: S25W81

11644 2013.01.01
2013.01.02
1 1 1 N15W72 0020 HSX AXX  
11648 2013.01.02
2013.01.04
      N05W55         plage
11646 2013.01.02
2013.01.03
      N13W64           plage
11651 2013.01.02
2013.01.04
      N20W60           plage
11649 2013.01.03
2013.01.04
3 5 2 S16W35 0060 CAO CAO area: 0080
S2156 2013.01.03       N17W59           plage
11650 2013.01.04 3 15 9 S28W30 0060 CAO CSO

location: S30W27

area:: 0090

11652 2013.01.05 16 40 19 N19W14 0210 EAI DAI

beta-gamma

11653 2013.01.05 2     N09W21 0010 CAO     spotless
11654 2013.01.07 31 73 47 N08E18 0950 FKC FHC

beta-gamma-delta

area: 1400

S2162 2013.01.07       N20W40           plage
S2163 2013.01.07       S19W59           plage
11657 2013.01.08
2013.01.11
      S17E09         plage
11655 2013.01.08
2013.01.09
2 6 1 S21W37 0010 BXO BXO  
S2167 2013.01.09   2 1 S33E03 0000   AXX  
S2168 2013.01.09       N11W00           plage
11656 2013.01.09
2013.01.11
7 8 5 N22E39 0030 CRO DRO

location: N22E42

S2170 2013.01.09       S14W40          
S2171 2013.01.11       S04W11         plage
S2172 2013.01.12   4 1 S12E77 0070   CAO    
Total spot count: 66 155 87  
Sunspot number: 156 255 187  (total spot count + 10 * number of spotted regions)
Weighted SN: 109 189 125  (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): 94 89 103 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)
2011.10 137.3 88.0 59.9 (+0.4) 8.28
2011.11 153.5 (cycle max) 96.7 (cycle max) 61.1 (+1.2) 5.55
2011.12 141.3 73.0 63.4 (+2.3) 3.78
2012.01 132.5 58.3 65.5 (+2.1) 7.15
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 (57.4 projected, -1.5) 13.90
2012.08 115.4 63.1 (58.3 projected, +0.9) 7.96
2012.09 122.9 61.5 (58.9 projected, +0.6) 8.07
2012.10 123.3 53.3 (58.3 projected, -0.6) 9.97
2012.11 121.3 61.4 (57.6 projected, -0.7) 7.08
2012.12 108.6 40.8 (56.9 projected, -0.7) 3.44
2013.01 148.8 (1) 58.0 (2A) / 149.9 (2B) / 65.9 (2C) (56.2 projected, -0.7) (2.14)

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.