Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 10, 2013 at 06:20 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 on March 9. Solar wind speed at SOHO ranged between 301 and 346 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 116.2 (increasing 9.1 over the last solar rotation). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 5.6). Three hour interval K indices: 22122121 (planetary), 21133221 (Boulder).

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

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

Region 11683 [S17W48] decayed slowly and quietly.
Region 11685 [S13W36] decayed slowly and quietly.
Region 11687 [N10W16] was quiet and stable.
Region 11689 [S19E02] developed slowly and quietly. There is minor polarity intermixing.
Region 11690 [N23E31] decayed slowly and quietly.
Region 11691 [N12E28] developed slowly and quietly.
New region 11692 [N09E78] rotated into view with a large spot.

Spotted regions not numbered by SWPC:
S2272 [N18W17] reemerged with several spots.
New region S2281 [N15E80] rotated into view.
New region S2282 [S22W35] emerged with a penumbra spot.
New region S2283 [S32W50] emerged with several spots early in the day, then decayed slowly.
New region S2284 [N27E07] emerged with a penumbra spot.

Coronal mass ejections (CMEs)

March 7-9: 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 (CH559) could rotate into an Earth facing position on March 11.

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 March 10-13. Effects from CH559 are possible on March 14-15 and could cause some unsettled intervals.

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
11683 2013.02.27   3 1 S15W51 0009   BXO

 

location: S17W48

11685 2013.02.28
2013.03.01
  3   S13W35 0006   AXX

 

11687 2013.03.02
2013.03.03
  20 6 N08W09 0045   BXO images\AR_11687_20130309_2345.jpg images/AR_11687_20130308_2345.jpg

location: N10W16

2K spot count includes one spot outside of image

11688 2013.03.03       S17W30           part of AR 11685, region should be deleted
11689 2013.03.03
2013.03.04
13 41 17 S19E02 0110 DAO CAI beta-gamma
S2269 2013.03.05       S30W28           plage
11690 2013.03.06 2 2 1 N23E29 0030 HSX CRO  
S2271 2013.03.06       S17E36           plage
S2272 2013.03.06   7 2 N18W17 0025   BXO    
S2273 2013.03.06       N20W36           plage
11691 2013.03.07
2013.03.08
7 14 8 N12E31 0040 CAO DAO  
S2278 2013.03.08       S18E24         plage
S2279 2013.03.08       S27W02         plage
11692 2013.03.09 1 1 1 N09E75 0250 HHX HHX    
S2281 2013.03.09   1 1 N15E80 0040   HSX    
S2282 2013.03.09   1   S22W25 0003   AXX    
S2283 2013.03.09   2   S32W50 0007   AXX    
S2284 2013.03.09   1   N27E07 0002   AXX    
Total spot count: 23 96 37  
Sunspot number: 63 216 117  (total spot count + 10 * number of spotted regions)
Weighted SN: 48 123 64  (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): 38 76 64 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) 6.11
2013.03 114.2 (1) 25.5 (2A) / 88.0 (2B) / 46.2 (2C) (51.5 projected, -1.0) (8.86)

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.