Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 18, 2014 at 04:45 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, 2014)] [Cycle 24 progress (last update March 1, 2014) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update March 1, 2014)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update March 1, 2014)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update March 1, 2014)]

[POES auroral activity level since October 2009 - updated January 26, 2013]
[Solar polar fields vs solar cycles - updated March 16, 2014]
[Presentation 3rd SSN Workshop, Tucson, 2013 (pdf)]

Recent activity

The geomagnetic field was quiet on March 17. Solar wind speed at SOHO ranged between 276 and 305 km/s.

Solar flux at 20h UTC on 2.8 GHz was 136.4 (decreasing 15.0 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 153.0. The Potsdam WDC planetary A index was 3 (STAR Ap - based on the mean of three hour interval ap indices: 3.4). Three hour interval K indices: 11110112 (planetary), 00102412 (Boulder).

The background x-ray flux is at the class B5 level.

At the time of counting spots (see image time) spots were observed in 14 active regions in 2K resolution (SN: 252) and 12 active regions in 1K resolution (SN: 175) SDO images on the visible solar disk.

Region 12002 [S17W57] decayed losing spots and penumbral area.
Region 12004 [S11W27] decayed slowly and quietly.
Region 12005 [N12E07] decayed in the trailing spot section.
Region 12008 [S12E47] decayed slowly and quietly.
Region 12009 [N12W17] decayed slowly and quietly.
New region 12010 [S15E68] rotated into view on March 16 and was numbered by SWPC the next day. The region developed on March 17 and has polarity intermixing.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3226 [S09E34] decayed slowly and quietly.
S3227 [S22E13] lost the leader spots while new trailing polarity penumbra spots emerged.
S3229 [S08E11] decayed slowly and quietly.
New region S3233 [S22E49] emerged with penumbra spots.
New region S3234 [S10E75] rotated into view.
New region S3235 [N13E85] rotated into view.
New region S3236 [S27E70] emerged with penumbra spots.
New region S3237 [S23E40] emerged with a penumbra spot.

Coronal mass ejections (CMEs)

March 15-17: 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 small trans equatorial coronal hole (CH608) could rotate into an Earth facing position on March 19-20.

Coronal hole map

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle latitudes is poor to fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet on March 18-21. Effects from CH608 could cause a weak disturbance on March 22-23.

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 Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
12002 2014.03.07
2014.03.08
21 31 15 S18W58 0220 EAC EAI

beta-gamma

location: S17W57

area: 0150

12004 2014.03.09
2014.03.10
3 18 6 S10W31 0010 BXO CRO images/AR_12004_20140316_2345.png

location: S11W27

area: 0035

S3208 2014.03.10       N09W34         plage
12005 2014.03.11
2014.03.12
4 24 11 N13E05 0250 CHO FKO images/AR_12005_20140317_2345.png area: 0390

location: N12E07

S3213 2014.03.12       N20W58           plage
12007 2014.03.13
2014.03.14
3     N11E23 0010 BXO       trailing spots of AR 12005

only one polarity present in the trailing section, BXO is not possible

12009 2014.03.13
2014.03.16
4 6 5 N14W16 0010 BXO BXO location: N12W17
S3216 2014.03.13       S01W30           plage
S3217 2014.03.13       S26W34           plage
12008 2014.03.14
2014.03.15
2 4 3 S11E45 0020 CRO CRO  
S3225 2014.03.15       S15E36         plage
S3226 2014.03.15   3 1 S09E34 0008   AXX  
S3227 2014.03.15   3 2 S22E13 0007   AXX  
S3229 2014.03.16   1   S08E11 0002   AXX  
12010 2014.03.16
2014.03.17
3 13 6 S14E64 0010 BXO DRI beta-gamma
S3231 2014.03.16       S19E26         plage
S3232 2014.03.16       S24E22         plage
S3233 2014.03.17   3 2 S22E49 0012   BXO    
S3234 2014.03.17   2 2 S10E75 0020   AXX    
S3235 2014.03.17   1 1 N13E85 0040   HAX    
S3236 2014.03.17   2 1 S27E70 0005   AXX    
S3237 2014.03.17   1   S23E40 0002   AXX    
Total spot count: 40 112 55  
Sunspot number: 110 252 175  (total spot count + 10 * number of spotted regions)
Weighted SN: 58 141 84  (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): 66 88 96 k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for MSN 2K, k = 0.55 for MSN 1K (MSN=Magnetic Sunspot Number)

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO)
Smoothed sunspot number Average ap
(3)
Measured 1 AU
2012.11 121.3 118.3 61.8 59.7 (+1.1) 7.08
2012.12 108.6 105.0 40.8 59.6 (-0.1) 3.44
2013.01 127.1 123.1 62.9 58.7 (-0.9) 4.69
2013.02 104.3 101.8 38.0 58.4 (-0.3) 6.11
2013.03 111.3 110.2 57.9 57.5 (-0.9) 10.56
2013.04 124.8 125.9 72.4 57.9 (+0.4) 5.40
2013.05 131.4 134.3 78.7 59.9 (+2.0) 9.73
2013.06 110.1 113.7 52.5 62.6 (+2.7) 12.60
2013.07 115.5 119.3 57.0 65.5 (+2.9) 9.47
2013.08 114.6 118.3 66.0 69.0 (+3.5) 8.27
2013.09 102.6 103.7 36.9 (72.8 projected, +3.8) 5.23
2013.10  132.1 131.2 85.6 (73.8 projected, +1.0) 7.71
2013.11  148.3 145.1 77.6 (72.7 projected, -1.1) 5.68
2013.12 147.7 143.1 90.3 (71.6 projected, -1.1) 4.68
2014.01 157.4 152.4 82.0 (71.6 projected, 0.0) 5.44
2014.02 170.3
(cycle peak)
166.3 102.8 (cycle peak) (70.9 projected, -0.7) 10.70
2014.03 149.7 (1)   80.2 (2A) / 146.2 (2B) / 115.8 (2C) (71.0 projected, +0.1) (4.4)

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 WDC-SILSO 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 GFZ Potsdam WDC ap indices.

This report has been prepared by Jan Alvestad. It is based on the 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.