Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 28, 2014 at 06:30 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 27. Solar wind speed at SOHO ranged between 357 and 471 km/s.

Solar flux at 20h UTC on 2.8 GHz was 144.8 (decreasing 25.8 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 154.8. The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.4). Three hour interval K indices: 11112110 (planetary), 11242411 (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: 274) and 13 active regions in 1K resolution (SN: 205) SDO images on the visible solar disk.

Region 12010 [S13W64] decayed further and was quiet with the exception of a C4 flare.
Region 12014 [S13W34] decayed slowly and quietly.

Region 12017 [N10W08] decayed slowly and quietly. The region has minor polarity intermixing.
Region 12018 [N03W03] was quiet and stable.
New region 12019 [S10W76] emerged on March 26 and was numbered the next day by SWPC as the region was decaying.
New region 12020 [S13E28] emerged on March 24, was spotless the next day and reemerged with several spots on March 26 with SWPC numbering the region on March 27.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3248 [N01W23] lost the southern spots and gained penumbra spots further north.
S3262 [S11E04] gained a few penumbra spots.
S3266 [S22W27] developed slowly and quietly.
S3267 [S22E45] gained a trailing penumbra spot.
New region S3269 [S15W50] emerged with several spots early in the day, then decayed and had a penumbra spot left by the end of the day.
New region S3270 [N17E78] rotated into view.
New region S3271 [S23E20] emerged with several spots.
New region S3272 [N18E18] emerged with penumbra spots in an old plage region.

Coronal mass ejections (CMEs)

March 25-27: 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 trans equatorial coronal hole (CH609) will rotate 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.

Forecast

The geomagnetic field is expected to be quiet on March 28-30. On March 31 and April 1 there's a chance of unsettled intervals due to coronal hole 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
17 17 8 S15W68 0080 DAO DRI

location: S13W64

12012 2014.03.17
2014.03.18
      S09W65           plage

location: S16W50

12013 2014.03.17
2014.03.18
      N15W53         plage
12016 2014.03.17
2014.03.22
      S28W63           plage
12014 2014.03.18
2014.03.19
35 26 18 S15W32 0290 EHI DSI

location: S13W34

S3248 2014.03.20   2 1 N01W23 0006   BXO  
12017 2014.03.21
2014.03.22
16 29 16 N10W07 0160 DSI DAI

beta-gamma

S3255 2014.03.22       S12W12           plage
S3256 2014.03.22       S08W13           plage
S3259 2014.03.23       S20W13           plage
12018 2014.03.24 9 17 12 N03W04 0070 DSI DRI  
12020 2014.03.24
2014.03.27
5 16 7 S14E28 0010 BXO BXI area: 0030
S3262 2014.03.24   9 3 S11E04 0020   AXX  
S3263 2014.03.25       S39W33           plage
S3264 2014.03.26       N08E39         plage
12019 2014.03.26
2014.03.27
3 1 1 S10W76 0010 BXO AXX  
S3266 2014.03.26   3 2 S22W27 0010   BXO  
S3267 2014.03.26   4 1 S22E45 0010   BXO  
S3269 2014.03.27   1 1 S15W50 0003   AXX    
S3270 2014.03.27   1 1 N17E78 0040   HAX    
S3271 2014.03.27   5 4 S23E20 0020   CRO    
S3272 2014.03.27   3   N18E18 0007   BXO images/AR_S3272_20140327_2345.png    
Total spot count: 85 134 75  
Sunspot number: 145 274 205  (total spot count + 10 * number of spotted regions)
Weighted SN: 110 158 99  (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): 87 96 113 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
2014.03 150.3 (1)   123.9 (2A) / 142.3 (2B) / 118.0 (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.