Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 6, 2013 at 03:00 UTC.

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

[POES auroral activity level since October 2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated February 3, 2013]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was quiet to unsettled on March 5. Solar wind speed at SOHO ranged between 331 and 415 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 118.4 (increasing 15.2 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: 4.4). Three hour interval K indices: 31111111 (planetary), xxxxxxxx (Boulder).

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

At midnight UTC the visible solar disk had 8 spotted active regions (in 2K resolution SDO images).

Region 11681 [N17W42] was quiet and stable.
Region 11683 [S16E03] decayed slowly and quietly.
Region 11685 [S17E25] decayed slowly and quietly.
Region 11686 [S13W61] lost the magnetic delta structure after the M flare. C flares are possible as there still is polarity intermixing. Flare: M1.2 at 07:54 UTC.
Region 11687 [N09E39] was quiet and stable.
Region 11689 [S18E57] developed slowly and quietly.

Spotted regions not numbered by SWPC:
New region S2269 [S30E24] emerged with a penumbra spot.
New region S2270 [N03W15] emerged with a penumbra spot.

An active region 4-5 days behind the northeast limb produced a flare at 04:26 UTC. A large full halo CME was observed afterwards.

Coronal mass ejections (CMEs)

March 3-5: 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 southern hemisphere coronal hole (CH558) was in an Earth facing position on March 3.

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 poor. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet to unsettled on March 6-7 due to possible effects from CH558 and quiet on March 8.

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
11682 2013.02.21
2013.02.25
2     S18W94 0060 CAO    

rotated out of view

11680 2013.02.24
2013.02.25
      S28W69           plage
11681 2013.02.24
2013.02.25
  3   N17W49 0007   BXO

location: N17W42

11686 2013.02.26
2013.03.03
11 19 10 S13W59 0100 DAC DAI beta-gamma
11683 2013.02.27 11 20 8 S15E01 0080 DAO CRO area: 0050

location: S16E03

 

S2261 2013.02.27       S10W29           plage
11685 2013.02.28
2013.03.01
2 10 5 S14E16 0010 BXO CRO area: 0020

location: S17E25

11684 2013.03.01       N17W43           part of AR 11681

should be deleted

S2264 2013.03.01       S18W14           plage
11687 2013.03.02
2013.03.03
4 9 4 N10E46 0010 BXO BXO  
S2266 2013.03.02       N09W45           plage
11688 2013.03.03 3     S15E24 0030 CSO       part of AR 11685, region should be deleted
11689 2013.03.03
2013.03.04
3 18 7 S19E54 0010 BXO CRI location: S18E57

area: 0060

S2268 2013.03.03       S33W11           plage
S2269 2013.03.05   1   S30E24 0003   AXX    
S2270 2013.03.05   1   N03W15 0002   AXX    
Total spot count: 36 81 34  
Sunspot number: 106 161 84  (total spot count + 10 * number of spotted regions)
Weighted SN: 56 95 48  (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): 64 56 46 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 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 57.7 (-1.2) 13.90
2012.08 115.4 63.0 58.1 (+0.4) 7.96
2012.09 122.9 61.4 (57.9 projected, -0.2) 8.07
2012.10 123.3 53.3 (57.0 projected, -0.9) 9.97
2012.11 121.3 61.4 (56.1 projected, -0.9) 7.08
2012.12 108.6 40.8 (54.9 projected, -1.2) 3.44
2013.01 127.1 62.9 (53.6 projected, -1.3) 4.69
2013.02 104.3 38.0 (52.5 projected, -1.1) 5.48
2013.03 113.7 (1) 16.2 (2A) / 100.4 (2B) / 42.8 (2C) (51.5 projected, -1.0) (12.93)

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.