Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 30, 2014 at 07:20 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, 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 to unsettled on March 29. Solar wind speed at SOHO ranged between 372 and 479 km/s.

Solar flux at 20h UTC on 2.8 GHz was 142.7 (decreasing 18.6 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 155.1 (new high for cycle 24). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.0). Three hour interval K indices: 32110103 (planetary), 33122313 (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 13 active regions in 2K resolution (SN: 252) and 13 active regions in 1K resolution (SN: 187) SDO images on the visible solar disk.

Region 12014 [S13W63] decayed slowly and quietly.
Region 12017 [N10W36] redeveloped a magnetic delta structure and produced an impulsive X1 flare as well as several low level C flares. C5+ flare: X1.0/2B at 17:48 UTC, the flare was associated with an asymmetric full halo CME.
Region 12018 [N04W28] decayed slowly and quietly.
Region 12020 [S15W05] decayed slowly and quietly.
Region 12021 [S13E37] developed slowly and was mostly quiet.
Region 12022 [N17E51] was quiet and stable.
New region 12023 [S16W79] emerged on March 28 and was numbered by SWPC the next day.
New region 12024 [N18E20] emerged on March 28 and received its NOAA number the following day.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3271 [S23W07] was quiet and stable.
S3276 [S11E27] was quiet and stable.
S3277 [S27E27] lost the westernmost spots and was quiet.
New region S3281 [S07W29] emerged early in the day with one umbra, then decayed slowly losing the umbra by the end of the day.
New region S3282 [S18W32] emerged with penumbra spots.

Coronal mass ejections (CMEs)

March 27-28: 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. Propagation on long distance northeast-southwest paths is poor to fair.

Forecast

The geomagnetic field is expected to be quiet on March 30 becoming quiet to unsettled with occasional active intervals on March 31 and April 1 due to coronal hole and CME effects.

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
12010 2014.03.16
2014.03.17
3     S13W90 0010 BXO    

rotated out of view

12013 2014.03.17
2014.03.18
      N15W81           plage
12014 2014.03.18
2014.03.19
13 14 5 S14W60 0210 CSO CSO area: 0300
S3248 2014.03.20       S03W48         plage
12017 2014.03.21
2014.03.22
11 27 10 N10W34 0100 DAO DAC

beta-gamma-delta

area: 0220

location: N10W36

S3255 2014.03.22       S12W38           plage
S3256 2014.03.22       S08W39           plage
S3259 2014.03.23       S20W39           plage
12018 2014.03.24 4 7 4 N03W29 0010 BXO BXO  
12020 2014.03.24
2014.03.27
  1 1 S14W00 0010   AXX images/AR_12020_20140328_2345.png location: S15W05
S3262 2014.03.24       S11W22           plage
S3264 2014.03.26       N08E13           plage
S3266 2014.03.26       S22W53           plage
S3267 2014.03.26       S22E19           plage
12022 2014.03.27
2014.03.28
1 1 1 N16E50 0050 HAX HSX  
S3271 2014.03.27   12 4 S23W07 0025   BXO images/AR_S3271_20140329_2345.png images/AR_S3271_20140328_2345.png  
S3272 2014.03.27       N12W08         images/AR_S3272_20140328_2345.png plage
12021 2014.03.28 12 26 17 S15E36 0050 DAO DAI area: 0110
S3274 2014.03.28       S30W81         plage
12024 2014.03.28
2014.03.29
1 9 4 N17E19 0010 AXX AXX  
S3276 2014.03.28   4 3 S11E27 0015   BXO  
S3277 2014.03.28   4 4 S27E27 0015   BXO images/AR_S3277_20140328_2345.png  
S3278 2014.03.28       S17E07         plage
12023 2014.03.28
2014.03.29
7 3 1 S16W79 0030 CAO BXO area: 0015
S3280 2014.03.28       N09E13         plage
S3281 2014.03.29   2 1 S07W29 0006   AXX    
S3282 2014.03.29   2 2 S18W32 0012   BXO    
Total spot count: 52 112 57  
Sunspot number: 132 252 187  (total spot count + 10 * number of spotted regions)
Weighted SN: 77 132 77  (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): 79 88 103 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
2014.03 149.9 (1)   132.5 (2A) / 141.7 (2B) / 114.9 (2C) (71.0 projected, +0.1) (5.0)

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.