Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 26, 2014 at 06:15 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 24. Solar wind speed at SOHO ranged between 346 and 516 km/s. A disturbance related to the CME observed early on March 23 was observed arriving at ACE near 19:25 UTC.

Solar flux at 20h UTC on 2.8 GHz was 152.8 (decreasing 25.6 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 154.3. The Potsdam WDC planetary A index was 8 (STAR Ap - based on the mean of three hour interval ap indices: 8.0). Three hour interval K indices: 11122133 (planetary), 0012233x (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 11 active regions in 2K resolution (SN: 268) and 9 active regions in 1K resolution (SN: 178) SDO images on the visible solar disk.

Region 12008 [S12W60] decayed slowly and quietly.
Region 12010 [S13W39] decayed slowly and was mostly quiet.
Region 12012 [S16W23] decayed slowly and quietly.
Region 12013 [N14W22] decayed and had only penumbra spots left.
Region 12014 [S13W07] decayed slowly and was quiet.

Region 12015 [S13W68] decayed barely retaining positive polarity umbra.
Region 12017 [N10E20] was quiet and stable.
Region 12018 [N03E25] was quiet and stable.

Spotted regions not numbered (or interpreted differently) by SWPC:
S3248 [S01E03] was quiet and stable.
S3262 [S13E33] was quiet and stable.
New region S3263 [S39W07] emerged at a high latitude with a penumbra spot.

Coronal mass ejections (CMEs)

March 24-25: No obviously Earth directed CMEs were observed in LASCO and STEREO imagery.
March 23: An asymmetric full halo CME was observed after the C5 LDE in AR 12014. The CME reached Earth late on March 25.

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

No obvious coronal holes are currently in or near Earth facing positions.

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 to active on March 26 due to CME effects and quiet on March 27-28.

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
12008 2014.03.14
2014.03.15
  1   S07W75 0001   AXX

SWPC has moved the region many degrees to the west

real location: S12W60

12015 2014.03.15
2014.03.22
1 2 2 S12W69 0070 DAC DAO

location: S13W68

erroneous SWPC data, DAC and 1 spot is impossible 

12010 2014.03.16
2014.03.17
17 42 22 S14W40 0170 DAI DAI

location: S13W39

S3233 2014.03.17       S27W48           plage
12012 2014.03.17
2014.03.18
  2   S09W37 0005   AXX location: S16W23
12013 2014.03.17
2014.03.18
1 9 1 N14W22 0010 AXX BXO  
12016 2014.03.17
2014.03.22
      S28W35         plage
12014 2014.03.18
2014.03.19
22 56 34 S13W05 0240 ESC EHI

location: S13W07

area: 0350

S3241 2014.03.18       N14W52           plage
S3244 2014.03.19       N17W37           plage
S3248 2014.03.20   7 3 S01E03 0016   AXX  
12017 2014.03.21
2014.03.22
9 22 13 N10E20 0130 DSI DSI

area: 0260

S3254 2014.03.21       S02W46           plage
S3255 2014.03.22       S12E14         plage
S3256 2014.03.22       S08E13           plage
S3259 2014.03.23       S20E13           plage
12018 2014.03.24 4 13 10 N02E25 0030 CRO DRI area: 0070

location: N03E25

S3261 2014.03.24       S12E57         plage
S3262 2014.03.24   3 2 S13E33 0012   AXX  
S3263 2014.03.25   1 1 S39W07 0004   AXX    
Total spot count: 54 158 88  
Sunspot number: 114 268 178  (total spot count + 10 * number of spotted regions)
Weighted SN: 77 186 116  (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): 68 94 98 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
2014.03 150.4 (1)   115.3 (2A) / 143.0 (2B) / 119.5 (2C) (71.0 projected, +0.1) (4.8)

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.