Solar Terrestrial Activity Report

Last major update issued on November 7, 2012 at 05:55 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 on November 6. Solar wind speed at SOHO ranged between 271 and 335 km/s. Solar wind speed increased slowly during the latter half of the day and a minor disturbance began early on November 7.

Solar flux measured at 20h UTC on 2.8 GHz was 98.7 (decreasing 13.3 over the last solar rotation). The Potsdam WDC planetary A index was 5 (STAR Ap - based on the mean of three hour interval ap indices: 4.9). Three hour interval K indices: 11111212 (planetary), 00122312 (Boulder).

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

At midnight UTC the visible solar disk had 9 spotted active regions (in 2K resolution SDO images).

Region 11602 [S22W36] reemerged with tiny spots.
Region 11604 [N08E09] was quiet and stable.
Region 11605 [N17W02] decayed slowly and quietly.
Region 11606 [S17E20] was quiet and stable.
Region 11607 [N12W59] developed slowly and was mostly quiet.
Region 11608 [S21E51] was quiet and stable.
New region 11609 [S15E73] rotated partly into view on November 5.

Spotted regions not numbered by NOAA/SWPC:
New region S2036 [S23E68] emerged near the southeast limb.
New region S2037 [N23W23] emerged with a tiny spot.

Coronal mass ejections (CMEs)

November 4-6: 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

An area with poorly defined corona rotated across the central meridian on November 5 and could cause a minor enhancement in geomagnetic activity on November 8-9.

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 to fair. Propagation on long distance northeast-southwest paths is poor to fair.

Forecast

The geomagnetic field is expected to be quiet to unsettled with a chance of active intervals on November 7 and mostly quiet on November 8-9. There's a small chance of unsettled intervals on Nov. 8-9 due to a weak coronal hole stream.

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
11602	2012.10.28 2012.10.29		4		S19W43	0000		BXO			location: S22W36
S2022	2012.10.30				N02W42						plage
11603	2012.10.30 2012.11.01				N08W88						plage
11605	2012.11.01 2012.11.04	1	4	1	N18W04	0010	AXX	BXO
11604	2012.11.02 2012.11.03		3	1	N07E05	0000		BXO
S2028	2012.11.02				N26W09						plage
11606	2012.11.04	1	5	2	S15E18	0010	AXX	BXO			location: S17E20
11608	2012.11.04 2012.11.05	1	1	1	S20E48	0020	HRX	HRX			location: S21E51
S2030	2012.11.04				N07W49						plage
11607	2012.11.04 2012.11.05	7	7	4	N12W61	0060	CSO	DAO
S2032	2012.11.04				N12W58						plage
S2033	2012.11.05				S18E31						plage
11609	2012.11.05 2012.11.06	1	4	3	S14E71	0030	HRX	DRO
S2035	2012.11.05				S12W43						plage
S2036	2012.11.06		2	2	S23E68	0020		CRO
S2037	2012.11.06		1		N23W23	0000		AXX
Total spot count:		11	31	14
Sunspot number:		61	121	84	(total spot count + 10 * number of spotted regions)
Weighted SN:		22	45	28	(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):		37	42	46	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.