Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 22, 2015 at 05:30 UT.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update March 1, 2015)] [Cycle 24 progress (last update March 1, 2015) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update March 1, 2015)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update March 1, 2015)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update March 1, 2015)]

[Noon SDO sunspot count 1K Reference: 4K (large file) (updated daily)]

[POES auroral activity level October 2009 - December 2012]
[Solar polar fields vs solar cycles - updated March 15, 2015]
[Presentations: 3rd SSN Workshop, Tucson, 2013 (pdf) / 4th SSN Workshop, Locarno, 2014]

Recent activity

The geomagnetic field was quiet to active on March 21. Solar wind speed at SOHO ranged between 553 and 754 km/s under the influence of a high speed stream.

Solar flux at 20h UTC on 2.8 GHz was 113.6 (decreasing 3.9 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 130.0. The Potsdam WDC planetary A index was 11 (STAR Ap - based on the mean of three hour interval ap indices: 10.6). Three hour interval K indices: 43332221 (planetary), 43332222 (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 using 2K resolution (SN: 161) and 10 active regions using 1K resolution (SN: 134) SDO images on the visible solar disk.

Region 12288 [S04W61] reemerged with penumbra spots.
Region 12303 [N19E12] was quiet and stable.
New region 12305 [S09E71] rotated into view on March 20 and was numbered by SWPC the next day.
New region 12306 [S17W51] emerged early in the day with several spots.

Spotted regions not numbered (or interpreted differently) by SWPC:
S4292 [S13E17] was quiet and stable.
S4293 [N17W31] developed slowly and quietly.
S4295 [S18E37] developed as new flux emerged.
S4298 [S08E54] was quiet and stable.
S4299 [N10E02] developed slowly and quietly.
S4302 [N09W11] was quiet and stable.
New region S4304 [S05W21] emerged with a penumbra spot.

C2+ flares (GOES):

Magnitude Peak time (UTC) Location AR Comment
         

Flare activity according to SDO/EVE/ESP XRS-B proxy

Coronal mass ejections (CMEs)

March 19-21: No obviously Earth directed CMEs were observed.

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 southern hemisphere coronal hole (CH660) rotated over the central meridian on March 19-22.

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 unsettled on March 22-25 with a chance of active intervals due to effects from CH660.

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
12299 2015.03.11
2015.03.12
  3 3 S04W68 0012   BXO  

location: S04W61

12303 2015.03.16
2015.03.17
1 7 5 N19E11 0120 HSX CSO area: 0170
12304 2015.03.18
2015.03.19
      N16W59          
S4291 2015.03.18       S05W21            
S4292 2015.03.18   5 2 S13E17 0014   BXO  
S4293 2015.03.19   3 3 N17W31 0013   CRO  
S4295 2015.03.19   11 6 S18E37 0040   CRO  
S4296 2015.03.19       N21E27          
S4297 2015.03.19       S12W26            
S4298 2015.03.19   1 1 S08E54 0003   AXX  
S4299 2015.03.20   2 2 N10E02 0015   CRO  
12305 2015.03.20
2015.03.21
5 7 5 S08E67 0120 DAO CKO area: 0320

location: S09E71

S4301 2015.03.20       S03E29          
S4302 2015.03.20   2   N09W11 0004   AXX  
12306 2015.03.21 4 9 6 S17W52 0020 CRO CRO    
S4304 2015.03.21   1 1 S05W21 0004   AXX    
Total spot count: 10 51 34  
Sunspot number: 40 161 134  (total spot count + 10 * number of spotted regions)
Weighted SN: 23 78 57  (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): 24 56 74 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
2013.10  132.1 131.2 85.6 75.0 (+1.9) 7.71
2013.11  148.3 145.1 77.6 75.4 (+0.4) 5.68
2013.12 147.7 143.1 90.3 76.0 (+0.6) 4.68
2014.01 157.4 152.4 81.8 77.3 (+1.3) 5.44
2014.02 170.3
(cycle peak)
166.3 102.3 (cycle peak) 78.4 (+1.1) 10.70
2014.03 149.9 148.5 91.9 80.8 (+2.4) 4.88
2014.04 143.9 144.8 84.7 81.9 (+1.1)
(likely solar max)
7.88
2014.05 129.7 132.9 75.2 80.5 (-1.4) 5.75
2014.06 122.0 125.8 71.0 79.7 (-0.8) 6.72
2014.07 137.4 141.8 72.5 78.6 (-1.1) 4.50
2014.08 124.7 127.9 74.7 75.6 (-3.0) 7.71
2014.09 146.6 148.1 87.6 (71.6 projected, -4.0) 9.78
2014.10 153.4 152.9 60.6 (69.2 projected, -2.4) 8.96
2014.11 154.8 151.4 70.1 (67.4 projected, -1.8) 9.33
2014.12 158.7 153.8 78.0 (66.3 projected, -1.1) 11.24
2015.01 141.9 137.3 67.0 (65.1 projected, -1.2) 9.46
2015.02 129.1 126.0 44.8 (63.6 projected, -1.5) 9.92
2015.03 (122.0)   31.9 (2A) / 47.1 (2B) / 51.8 (2C) (61.6 projected, -2.0) (17.9)

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.