Solar Terrestrial Activity Report

Activity chart

Last major update issued on March 1, 2016 at 04:30 UT.

Charts (* = updated daily) Data and archive
  Solar wind (*) Solar and geomagnetic data - last month (*)
  Electron fluence (*) Archived daily reports and monthly data from 2003.01 (February 1, 2016)
Solar cycle Solar cycles 23-24 (March 1, 2016) Historical solar and geomagnetic data charts 1954-2006 (April 5, 2007)
  Cycle 24 progress (March 1, 2016) Noon SDO sunspot count 1K Reference: 4K (large file) (*)
  Solar cycles 1-24 (July 17, 2015) POES auroral activity level October 2009 - December 2012
  Comparison of cycles 21, 22, 23 and 24 (March 1, 2016) 3rd SSN Workshop, Tucson, 2013
  Comparison of cycles 12, 13, 14, 16 and 24 (March 1, 2016) 4th SSN Workshop, Locarno, 2014
  Solar polar fields vs. solar cycles (January 29, 2016)  

Recent activity

The geomagnetic field was quiet on February 29. Solar wind speed at ACE ranged between 302 and 367 km/s. A coronal hole stream associated with CH717 was observed arriving at ACE just before 04 UT on March 1 and was preceded by weak effects from a co-rotating interaction region.

Solar flux at 20h UTC on 2.8 GHz was 90.9 (decreasing 11.2 over the last solar rotation). The 90 day 10.7 flux at 1 AU was 103.6. The Potsdam WDC planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.0). Three hour interval K indices: 20111002 (planetary), 20122212 (Boulder).

The background x-ray flux is at the class B2 level.

At the time of counting spots (see image time), spots were observed in 8 active regions using 2K resolution (SN: 127) and 5 active regions using 1K resolution (SN: 71) SDO images on the visible solar disk.

Region 12506 [S07W19] decayed slowly and quietly.
Region 12508 [N06W06] was quiet and stable.
New region 12509 [N09E17] rotated into view on February 25 and was numbered by SPWC 4 days later as the region began to decay.

Spotted regions not numbered (or interpreted differently) by SWPC:
S5124 [S25W34] was quiet and stable.
S5140 [S15E38] was quiet and stable.
New region S5141 [N09E11] emerged just west of AR 12509.
New region S5142 [N04E85] rotated partly into view.
New region S5143 [N24W06] was observed with a tiny spot.

C2+ flares:

Magnitude Peak time (UT) Location AR Recorded by Comment
           

Flare activity (SDO/EVE/ESP XRS-B proxy)

Coronal mass ejections (CMEs)

February 27-29: No obviously Earth directed CMEs were observed in available LASCO 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 recurrent trans equatorial coronal hole (CH717) was in an Earth facing position on February 26-27. A northern hemisphere coronal hole (CH719) will likely rotate into an Earth facing position on March 1. A trans equatorial coronal hole (CH718) will likely rotate across the central meridian on March 2.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over upper middle latitudes is fair. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet to active on March 1 and quiet to unsettled on March 2 due to effects from CH717. Quiet conditions are likely on March 3 becoming quiet to unsettled on March due to effects from CH719.

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). 4K 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 overlays
Comment
SWPC Magnetic
(SDO)
SWPC STAR Current Previous
2K 1K
S5121 2016.02.19       N12W51            
S5124 2016.02.21   5   S25W34 0007   BXO  
12506 2016.02.22
2016.02.24
9 19 12 S06W20 0130 DAI DSO images/AR_12506_20160229_2345.png images/AR_12506_20160228_2345.png

 

12509 2016.02.25
2016.02.29
4 6 2 N09E17 0020 BXO DRO  
S5131 2016.02.25       N20W20            
12508 2016.02.26
2016.02.28
1 7 3 N07W05 0010 AXX CRO area: 0025
S5134 2016.02.26       S07E19            
S5136 2016.02.27       S02W18            
S5137 2016.02.27       S21W10            
S5138 2016.02.28       N20E04          
S5139 2016.02.28       S01W52          
S5140 2016.02.28   2   S15E38 0003   BXO  
S5141 2016.02.29   5 3 N09E11 0015   DRO    
S5142 2016.02.29   2 1 N04E85 0060   CRO    
S5143 2016.02.29   1   N24W06 0001   AXX    
Total spot count: 14 47 21  
Sunspot number: 44 127 71  (total spot count + 10 * number of spotted regions)
Weighted SN: 19 64 38  (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): 48 57 57 k * (sunspot number)
As of February 19, 2015: k = 1.1 for SWPC, k = 0.45 for MSN 2K, k = 0.80 for MSN 1K (MSN=Magnetic Sunspot Number)

Monthly solar cycle data

Month Average solar flux International sunspot number
(WDC-SILSO) (4)
Smoothed sunspot number (4) Average ap
(3)
Measured 1 AU
2014.02 170.3
(cycle peak)
166.3 146.1 (cycle peak) 110.5 (+1.2) 10.70
2014.04 143.9 144.8 112.5 116.4 (+2.1) (solar max) 7.88
2014.12 158.7 153.8 112.9 92.2 (-2.5) 11.24
2015.01 141.9 137.3 93.0 89.3 (-2.9) 9.46
2015.02 129.1 126.0 66.7 86.1 (-3.2) 9.92
2015.03 125.9 124.6 54.5 82.2 (-3.9) 16.14
2015.04 128.8 129.7 75.3 78.8 (-3.4) 10.73
2015.05 120.0 122.6 88.8 76.0 (-2.8) 8.29
2015.06 122.3 126.1 66.5 72.0 (-4.0) 13.15
2015.07 107.0 110.8 66.4 68.2 (-3.8) 8.83
2015.08 105.4 108.0 64.6 66.3 (-1.9) 14.58
2015.09 101.7 102.7 78.1 (66.0 projected, -0.3) 15.78
2015.10 104.1 103.3 61.7 (65.3 projected, -0.7) 14.02
2015.11 109.3 106.9 63.2 (63.2 projected, -2.1) 12.09
2015.12 113.1 109.5 57.7 (61.5 projected, -1.7) 14.29
2016.01 103.4 100.1 56.6 (59.8 projected, -1.7) 9.4
2016.02 103.6 101.0 57.2 (57.4 projected, -2.4) 9.2
2016.03 ()   (2A/2B) / 77.8 (2C) (54.5 projected, -3.1) ()

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).
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.
4) Updated to new data set from WDC-SILSO on July 1, 2015

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 Universal Time. Comments and suggestions are always welcome.

SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.