Solar Terrestrial Activity Report

Last major update issued on November 24, 2012 at 05:10 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 November 4, 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 quiet to active on November 23. Solar wind speed at SOHO ranged between 282 and 402 (est.) km/s. A solar wind shock was observed at ACE at 21:13 UTC, the arrival of the CME observed on November 20

Solar flux measured at 20h UTC on 2.8 GHz was 126.7 (increasing 5.0 over the last solar rotation). The Potsdam WDC planetary A index was 6 (STAR Ap - based on the mean of three hour interval ap indices: 6.0). Three hour interval K indices: 00110014 (planetary), 11121114 (Boulder).

The background x-ray flux was at the class B3 level.

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

Region 11618 [N08W27] decayed further and currently appears to have no magnetic delta structures. C flares are possible.
Region 11619 [N10W70] was quiet and stable.
Region 11620 [S12E16] was quiet and stable.

Spotted regions not numbered by NOAA/SWPC:
S2059 [N08W22] was quiet and stable. The leader spot continues to slide slowly westwards along the southern edge of the trailing penumbra of AR 11618.
S2067 [S17W02] lost the spots observed the previous day and gained a trailing spot further east.
S2068 [N16W63] developed slightly and was quiet. For unknown reasons SWPC seems to count these spots as belonging to AR 11616 even if there clearly is two separate active regions.
New region S2070 [S23E57] emerged with a few spots.
New region S2071 [S20E18] emerged with tiny spots.

Coronal mass ejections (CMEs)

November 21: While most of the ejecta from the CME associated with the M3 event in AR 11618 was directed eastwards, components of the CME could be Earth directed.
November 22: A filament eruption was observed starting in the southeast quadrant just after 08h UTC. LASCO C3 observed a faint and slow CME off the east limb from 10:42 UTC while the CME was visible in STEREO imagery from 10:09 UTC. There may be a very weak Earth directed component associated with this CME.
November 23: A filament eruption in the southern hemisphere was observed starting at 11:42 and peaking just after 14h UTC. In LASCO imagery it is difficult to determine if this CME was geoeffective due to a CME with an origin in an active region behind the northeast limb occurring a little earlier. STEREO imagery indicate that a faint component of the CME could be Earth directed.

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.

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 good.

Forecast

The geomagnetic field is expected to be quiet to active on November 24 due to CME effects and quiet to unsettled on November 25-26 due to weak CME effects.

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
11616	2012.11.13 2012.11.14	4			N19W55	0030	DAO				spotless
11618	2012.11.15 2012.11.17	37	35	22	N08W27	0450	EKC	DKI
11619	2012.11.15 2012.11.17	2	2	2	N13W64	0180	HSX	HSX			location: N10W70
S2059	2012.11.16		5	3	N08W22	0030		CAO
S2060	2012.11.17				S13W29						plage
S2061	2012.11.18				S33W19						plage
11620	2012.11.18 2012.11.20	2	8	3	S13E16	0090	HAX	HAX			area: 0050
S2064	2012.11.19				S21E20						plage
S2065	2012.11.19				N13W36						plage
S2066	2012.11.20				S10W08						plage
S2067	2012.11.21		1		S17W00	0000		AXX
S2068	2012.11.21		6	4	N16W63	0080		DAO
S2069	2012.11.22				N18W10						plage
S2070	2012.11.23		4	1	S23E57	0010		BXO
S2071	2012.11.23		2		S20E18	0000		AXX
Total spot count:		45	63	35
Sunspot number:		85	143	95	(total spot count + 10 * number of spotted regions)
Weighted SN:		70	93	65	(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):		51	50	52	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

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.