Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 19, 2014 at 05:30 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 18. Solar wind speed at SOHO ranged between 274 and 339 km/s.

Solar flux at 20h UTC on 2.8 GHz was 138.3 (decreasing 19.3 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 152.9. The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.5). Three hour interval K indices: 11211111 (planetary), 12312321 (Boulder).

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

At the time of counting spots (see image time), spots were observed in 16 active regions in 2K resolution (SN: 297) and 14 active regions in 1K resolution (SN: 218) SDO images on the visible solar disk.

Region 12002 [S17W70] decayed slowly and quietly.
Region 12004 [S11W42] developed slowly and quietly.
Region 12005 [N12W07] decayed in the trailing spot section and lost all umbrae there. The leader spot was mostly unchanged.
Region 12008 [S12E32] was quiet and stable.
Region 12009 [N11W32] decayed slowly and quietly.
Region 12010 [S15E54] developed further. The region has polarity intermixing and a magnetic delta structure could easily form. A minor M class flare is possible. Several C flares were observed.
New region 12011 [S07W23] emerged with several spots.
New region 12012 [S09E62] rotated into view on March 17 and was numbered the next day by SWPC.
New region 12013 [N14E69] rotated into view on March 17 with SWPC numbering the region the following day.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3225 [S14E26] regained penumbra spots.
S3226 [S09E20] developed slowly and quietly.
S3233 [S22E37] decayed slowly and quietly.
S3236 [S27E58] was quiet and stable.
New region S3240 [S14E85] rotated into view.
New region S3241 [N15E40] emerged with penumbra spots.
New region S3242 [N21E08] emerged with a penumbra spot.

Coronal mass ejections (CMEs)

March 16-18: 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. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet on March 19-21. 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
10 12 6 S18W72 0130 CAO CAO

 

location: S17W70

area: 0090

12004 2014.03.09
2014.03.10
8 24 11 S10W45 0040 CAO DAO

location: S11W42

area: 0120

S3208 2014.03.10       N09W47           plage
12005 2014.03.11
2014.03.12
3 22 13 N13W09 0250 CHO CKO images/AR_12005_20140318_2345.png images/AR_12005_20140317_2345.png area: 0380

location: N12W07

12007 2014.03.13
2014.03.14
1     N11E09 0010 AXX       trailing spots of AR 12005
12009 2014.03.13
2014.03.16
  3 2 N14W30 0012 BXO BXO location: N11W32
S3216 2014.03.13       S01W43           plage
S3217 2014.03.13       S26W47           plage
12008 2014.03.14
2014.03.15
1 8 5 S11E31 0010 HRX CRO area: 0022
S3225 2014.03.15   3 1 S14E26 0007   AXX    
S3226 2014.03.15   7 6 S09E20 0030   CRO  
S3227 2014.03.15       S22W00         plage
S3229 2014.03.16       S08W02         plage
12010 2014.03.16
2014.03.17
6 29 18 S15E54 0030 CRO DRI beta-gamma

area: 0100

S3231 2014.03.16       S19E13           plage
S3232 2014.03.16       S24E09           plage
S3233 2014.03.17   3   S22E37 0007   BXO  
12012 2014.03.17
2014.03.18
2 2 2 S09E61 0010 AXX HRX area: 0020
12013 2014.03.17
2014.03.18
1 1 1 N13E70 0030 HSX HSX area: 0060
S3236 2014.03.17   2 1 S27E58 0007   BXO  
S3237 2014.03.17       S23E27         plage
12011 2014.03.18 3 16 8 S07W22 0010 BXO DAI   area: 0090
S3240 2014.03.18   1 1 S14E85 0070   HAX    
S3241 2014.03.18   3 3 N15E40 0013   BXO    
S3242 2014.03.18   1   N21E08 0003   AXX    
Total spot count: 35 137 78  
Sunspot number: 125 297 218  (total spot count + 10 * number of spotted regions)
Weighted SN: 68 184 125  (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): 75 104 120 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
2014.03 149.1 (1)   84.2 (2A) / 145.1 (2B) / 116.9 (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.