Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 31, 2014 at 04:40 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 30. Solar wind speed at SOHO ranged between 350 and 445 km/s.

Solar flux at 20h UTC on 2.8 GHz was 148.4 (decreasing 12.6 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 155.2 (new high for cycle 24). The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 3.9). Three hour interval K indices: 21110111 (planetary), 20112321 (Boulder).

The background x-ray flux is at the class B9 level.

At the time of counting spots (see image time), spots were observed in 16 active regions in 2K resolution (SN: 292) and 14 active regions in 1K resolution (SN: 210) SDO images on the visible solar disk.

Region 12014 [S13W78] decayed slowly and quietly.
Region 12017 [N10W49] decayed and lost the magnetic delta structure during the day. There is still polarity intermixing and C flares are possible. C5+ flares: M2.1/1N at 11:55, C7.6 at 21:15 UTC.
Region 12018 [N05W42] decayed slowly and quietly.
Region 12020 [S15W13] decayed slowly and quietly.
Region 12021 [S12E25] developed slowly and was mostly quiet. C and minor M class flares are possible.
Region 12022 [N17E38] was quiet and stable.
Region 12024 [N18E08] was quiet and stable.
New region 12025 [S23W18] emerged on March 27 and was numbered by SWPC 3 days later.
New region 12026 [S11E79] rotated into view as a compact region with many small spots. The region has polarity intermixing. C and M class flaring is possible.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3276 [S11E13] was quiet and stable.
S3277 [S28E13] was quiet and stable.
S3281 [S08W37] was quiet and stable.
New region S3283 [S25W70] emerged with a few spots.
New region S3284 [N12E86] rotated partly into view.
New region S3285 [S12W10] emerged with a few spots.
New region S3286 [S06W60] emerged with penumbra spots.

Coronal mass ejections (CMEs)

March 28, 30: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
March 29: An asymmetric full halo CME was observed after the X1 flare in AR 12017. The leading edge of the CME will likely reach Earth sometime between late on March 31 and noon on April 1. The CME core was not Earth directed.

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 trans equatorial coronal hole (CH609) rotated into an Earth facing position on March 28-29.

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 to unsettled on March 31 due to effects from CH609. Quiet to active conditions are possible on April 1 due to CME and coronal hole effects, while April 2 could see quiet to unsettled conditions.

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: 0-30% probability, Yellow: 30-70% probability, Red: 70-100% 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
12014 2014.03.18
2014.03.19
5 4 2 S13W78 0200 CSO HSX area: 0220
12017 2014.03.21
2014.03.22
10 19 10 N10W49 0130 DAC DAI

beta-gamma

area: 0090

S3255 2014.03.22       S12W51           plage
S3256 2014.03.22       S08W52           plage
S3259 2014.03.23       S20W52           plage
12018 2014.03.24   2   N04W44 0003   BXO location: N05W42
12020 2014.03.24
2014.03.27
3 3 2 S13W11 0010   AXX location: S15W13

SWPC apparently includes the spots of AR S3285

S3262 2014.03.24       S11W35           plage
S3264 2014.03.26       N08W00           plage
S3267 2014.03.26       S22E06           plage
12022 2014.03.27
2014.03.28
1 8 4 N16E36 0040 HSX CAO area: 0060

location: N17E38

12025 2014.03.27
2014.03.30
3 12 4 S24W20 0030 DRO DRO images/AR_S3271_20140329_2345.png location: S23W18
S3272 2014.03.27       N12W21           plage
12021 2014.03.28 16 34 22 S15E22 0100 DAI DAC area: 0300
12024 2014.03.28
2014.03.29
  4 3 N17E05 0012   BXO  
S3276 2014.03.28   6 3 S11E13 0020   AXX  
S3277 2014.03.28   4 2 S28E13 0015   BXO  
S3278 2014.03.28       S17W06           plage
12023 2014.03.28
2014.03.29
1     S16W91 0010 AXX     rotated out of view
S3280 2014.03.28       N09W00           plage
S3281 2014.03.29   2   S08W37 0004   AXX  
S3282 2014.03.29       S18W45         plage
12026 2014.03.30 3 20 9 S11E76 0030 BXO DAC   beta-gamma

location: S11E79

area: 0110

S3283 2014.03.30   4 3 S25W70 0020   DRO    
S3284 2014.03.30   2 1 N12E86 0260   CHO    
S3285 2014.03.30   6 3 S12W10 0025   CRO    
S3286 2014.03.30   2 2 S06W60 0010   CRO    
Total spot count: 42 132 70  
Sunspot number: 122 292 210  (total spot count + 10 * number of spotted regions)
Weighted SN: 65 179 117  (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): 73 102 116 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
2014.03 149.8 (1)   136.5 (2A) / 141.0 (2B) / 114.0 (2C) (71.0 projected, +0.1) (4.9)

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.