Solar Terrestrial Activity Report

Activity chart

Last major update issued on November 2, 2012 at 05:00 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)]
[Solar cycles 23-24 (last update November 1, 2012)] [Cycle 24 progress (last update November 1, 2012) ]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update November 1, 2012)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update November 1, 2012)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update October 1, 2012)]

[POES auroral activity level since October 2009 - updated October 7, 2012]
[Solar polar fields vs solar cycles - updated June 27, 2011]

Recent activity

The geomagnetic field was unsettled to minor storm on November 1. Solar wind speed at SOHO ranged between 342 and 434 km/s under the influence of CME effects.

Solar flux measured at 20h UTC on 2.8 GHz was 98.4 (decreasing 7.8 over the last solar rotation). The Potsdam WDC planetary A index was 25 (STAR Ap - based on the mean of three hour interval ap indices: 24.8). Three hour interval K indices: 33344544 (planetary), 32343422 (Boulder).

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

At midnight UTC the visible solar disk had 8 spotted active regions (in 2K resolution SDO images).

Region 11598 [S11W77] decayed slowly and quietly as it rotated to the southwest limb.
Region 11599 [S12W50] was quiet and stable.
Region 11601 [S13W27] added a few spots.
Region 11602 [S20E26] gained a few tiny spots.
New region 11603 [N08W17] emerged on October 30 and was numbered by SWPC 2 days later.

Spotted regions not numbered by NOAA/SWPC:
S2020 [N11W05] gained a few tiny spots.
New region S2025 [N16E64] emerged with a few spots.
New region S2026 [S36W29] emerged with a single tiny spot in an old plage area.

Coronal mass ejections (CMEs)

October 30 - November 1: 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 coronal hole (CH543) was in an Earth facing position on October 31 and has moved southwards over the last days and could merge with CH544. A recurrent coronal hole (CH544) in the southern hemisphere was in an Earth facing position on November 1.

Coronal hole map

The above coronal hole map is based on a method where coronal holes are detected automatically. While the method may need some fine tuning, it has significant advantages over detecting coronal holes manually. The main improvement is the ability to detect coronal holes at and just beyond the solar limbs. Early results using this method for SDO images over a span of several weeks indicate a good match between coronal holes observed over the visible disk and their extent and position at the east and west limbs. Note that the polar coronal holes are easily detected using this method, the extent and intensity of both CHs are consistent with other data sources.

Propagation

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

Forecast

The geomagnetic field is expected to be mostly quiet on November 2. Quiet to unsettled is possible on November 3 due to effects from CH543, becoming unsettled to minor storm on November 4-5 as a stream from CH544 reaches Earth.

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: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% probability.

Active solar regions

Click on image for higher resolution image) 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 (blue-green) 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 STAR SDO SWPC STAR Current Previous
2K 1K
11598 2012.10.20 2 3 3 S11W77 0160 HSX CAO

 

11599 2012.10.22
2012.10.23
1 2 1 S11W49 0100 HSX HSX area: 0180
11601 2012.10.25
2012.10.29
  6   S10W33 0000   AXX location: S13W27
S2015 2012.10.27       S21W59           plage
11602 2012.10.28
2012.10.29
3 8 3 S19E27 0080 CAO CAO  
S2017 2012.10.28       N15W53           plage
S2019 2012.10.28       N10W34           plage
S2020 2012.10.29   4   N11W05 0000   BXO  
S2021 2012.10.29       N17W17           plage
S2022 2012.10.30       N03E26           plage
11603 2012.10.30
2012.11.01
2 3 2 N08W18 0010 BXO BXO  
S2024 2012.10.30       N34W29           plage
S2025 2012.11.01   3 1 N16E64 0010   BXO    
S2026 2012.11.01   1   S36W29 0000   AXX    
Total spot count: 8 30 10  
Sunspot number: 48 110 60  (total spot count + 10 * number of spotted regions)
Weighted SN: 23 45 25  (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): 28 39 33 k * (sunspot number). k = 0.6 for SWPC, k = 0.35 for STAR SDO 2K, k = 0.55 for STAR SDO 1K

Monthly solar cycle data

Month Average measured solar flux International sunspot number (SIDC) Smoothed sunspot number Average ap
(3)
2011.09 133.8 78.0 59.5 (+0.5) 12.27
2011.10 137.3 88.0 59.9 (+0.4) 8.28
2011.11 153.5 96.7 61.1 (+1.2) 5.55
2011.12 141.3 73.0 63.4 (+2.3) 3.78
2012.01 132.5 58.3 65.5 (+2.1) 7.15
2012.02 106.5 32.9 66.9 (+1.4)
possible cycle 24 max
8.81
2012.03 114.7 64.3 66.8 (-0.1) 16.08
2012.04 113.0 55.2 64.6 (-2.2) 10.10
2012.05 121.5 69.0 (61.2 projected, -3.4) 7.06
2012.06 119.6 64.5 (58.8 projected, -2.4) 10.08
2012.07 133.9 66.5 (58.6 projected, -0.2) 13.90
2012.08 115.4 63.1 (60.4 projected, +1.8) 7.96
2012.09 122.9 61.5 (61.8 projected, +1.4) 8.07
2012.10 123.3 53.3 (61.5 projected, -0.3) 10.40
2012.11 98.4 (1) 1.6 (2A) / 48.0 (2B) / 50.1 (2C) (61.2 projected, -0.3) (24.75)

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 SIDC 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 Potsdam WDC ap indices.

This report has been prepared by Jan Alvestad. It is based on 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.