Solar Terrestrial Activity Report

Last major update issued on November 5, 2011 at 06:50 UTC.

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-24 (last update November 1, 2011)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update November 1, 2011)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update November 1, 2011)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update November 2, 2011)]

[POES auroral activity level since October 2009 - updated November 4, 2011]
Annotated geomagnetic activity charts - Carrington rotation 2114 [August-September 2011] - 2115 [September-October 2011] NEW
[Solar polar fields vs solar cycles - updated June 27, 2011]

Recent activity

The geomagnetic field was quiet on November 4. Solar wind speed ranged between 271 and 424 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 163.9 (increasing 45.5 over the last solar rotation). The planetary A index was 4 (STAR Ap - based on the mean of three hour interval ap indices: 4.0). Three hour interval K indices: 00111112 (planetary), 00122212 (Boulder).

The background x-ray flux is at the class C1 level.

At midnight UTC the visible solar disk had 7 spotted regions (in 2K resolution SDO images).

Region 11334 [N13W47] lost the trailing spots and was quiet.
Region 11336 [N13W01] decayed slowly and quietly. The region could soon become spotless
Region 11337 [N18E13] decayed slowly and quietly.
Region 11338 [S13E28] appears to be decaying slowly. None of the trailing spots have penumbra.
Region 11339 [N20E45] is a complex, compact, very large region with the potential to produce major flares. There is a significant magnetic delta structure in the central part. Although the region became less active on November 4, further M class flaring is likely, another X class flare would be no surprise. Flares: C3.8 at 00:11, C2.9 at 19:33, M1.0 at 20:46, C4.6 at 22:43 UTC. The region was the source of a long duration M3.7 event peaking at 03:35 on November 5.

Spotted regions not reported by NOAA/SWPC:
[S1310] rotated into view at the southeast limb on November 4. Location at midnight: S09E78
[S1311] emerged in the northeast quadrant on November 4. Location at midnight: N16E25

A region just behind the northeast limb has M class flare potential. The region produced a C5.4 flare at 01:01 and a C8.6 flare at 03:53 UTC.

Coronal mass ejections (CMEs)

November 2-4: No obviously Earth directed CMEs observed.

Coronal holes

Coronal hole history (since late October 2002)
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago

A small coronal hole (CH482) in the northern hemisphere was in an Earth facing position on October 31-November 1. A small coronal hole (CH484) in the northern hemisphere was in an Earth facing position on November 3.

The above coronal hole map is based on a new method where coronal holes are detected automatically. The method may need some fine tuning, however, 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 the new method, the extent and intensity of both holes 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 quiet to unsettled on November 5-7.

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

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 polarity overlay		Comment
		SWPC	STAR SDO			SWPC	STAR	Current	Previous
11332	2011.10.23 2011.10.24			N31W67						plage
11335	2011.10.28 2011.10.31			N12W40						plage location: N18W35
11336	2011.10.29 2011.10.31		3	N11W02	0000		BXO			location: N13W01
11334	2011.10.29 2011.10.30	2	2	N12W47	0070	HSX	HSX
11337	2011.10.30 2011.10.31	3	12	N18E14	0010	BXO	BXO
11338	2011.10.31 2011.11.01	10	21	S14E28	0240	DSO	CSO			area: 0350
S1304	2011.10.31			N22W46						plage
11339	2011.11.01	33	60	N19E45	1540	FKC	FKC			beta-gamma-delta location: N20E45
S1308	2011.11.03			S23E47						plage
S1309	2011.11.03			S22W01						plage
S1310	2011.11.04		1	S09E78	0080		HSX
S1311	2011.11.04		4	N16E25	0000		BXO
Total spot count:		48	103
Sunspot number:		88	173	(total spot count + 10 * number of spotted regions)
Classification adjusted SN:		68	128	(Sum of total spot count + classification adjustment for each AR. Classification adjustment: X=0, R=3, A/S=5, H/K=10)
Relative sunspot number (Wolf number):		53	78	k * (sunspot number). k = 0.6 for SWPC. k = 0.45 (changed from 0.33 on Nov.1) for STAR SDO

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) Month average to date.
3) Running average based on the preliminary daily SWPC ap indices. Values in red are based on the official NGDC 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.