Solar Terrestrial Activity Report

Last major update issued on November 25, 2012 at 07:40 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 minor storm on November 24. Solar wind speed at SOHO ranged between 346 and 451 km/s under the influence of CME effects. The interplanetary magnetic field was northwards after noon causing a decrease in the disturbance level.

Solar flux measured at 20h UTC on 2.8 GHz was 118.0 (increasing 1.0 over the last solar rotation). The Potsdam WDC planetary A index was 14 (STAR Ap - based on the mean of three hour interval ap indices: 14.3). Three hour interval K indices: 54323211 (planetary), 44434311 (Boulder).

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

At midnight UTC the visible solar disk had 12 spotted active regions (in 2K resolution SDO images).

Region 11618 [N09W40] decayed slowly and was mostly quiet.
Region 11619 [N10W84] was quiet and stable.
Region 11620 [S13E01] gained a few spots and was quiet.
New region 11621 [N15E78] rotated into view.

Spotted regions not numbered by NOAA/SWPC:
S2059 [N08W35] was quiet and stable. The leader spot decayed a little and is still at the southeast edge of a trailing AR 11618 penumbra.
S2066 [S08W23] reemerged with a tiny spot.
S2068 [N16W80] decayed slowly and quietly.
S2070 [S23E47] decayed and lost the leader spots.
New region S2072 [S17E52] emerged with a tiny spot.
New region S2073 [S11E33] emerged with a tiny spot.
New region S2074 [N15E09] emerged with a tiny spot.
New region S2075 [S05W05] emerged with a tiny spot.

Coronal mass ejections (CMEs)

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.
November 24: 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 recurrent trans equatorial coronal hole (CH546) will likely rotate into an Earth facing position on November 27.

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 poor.

Forecast

The geomagnetic field is expected to be quiet to unsettled on November 25-26 due to CME effects, there's a chance of active intervals. Quiet conditions are likely on November 27-28.

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	5			N19W69	0020	DAO				spotless
11618	2012.11.15 2012.11.17	22	33	17	N08W41	0340	EKC	DAC
11619	2012.11.15 2012.11.17	4	1	1	N13W78	0100	ESO	HSX			location: N10W84 SWPC data does not match reality
S2059	2012.11.16		4	2	N08W35	0020		CRO
S2060	2012.11.17				S13W42						plage
S2061	2012.11.18				S33W32						plage
11620	2012.11.18 2012.11.20	5	13	8	S12W00	0020	CSO	CRO			area: 0050
S2064	2012.11.19				S21E07						plage
S2065	2012.11.19				N13W49						plage
S2066	2012.11.20		1		S08W23	0000					plage
S2067	2012.11.21				S17W13						plage
S2068	2012.11.21		2	2	N16W80	0020		HRX
S2069	2012.11.22				N18W23						plage
S2070	2012.11.23		1		S23E47	0000		AXX
S2071	2012.11.23				S20E05						plage
11621	2012.11.24	1	1	1	N15E78	0060	HAX	HSX			area: 0180
S2072	2012.11.24		1	1	S17E52	0000		AXX
S2073	2012.11.24		1	1	S11E23	0000		AXX
S2074	2012.11.24		1	1	N15E09	0000		AXX
S2075	2012.11.24		1		S05W05	0000		AXX
Total spot count:		37	60	34
Sunspot number:		87	180	124	(total spot count + 10 * number of spotted regions)
Weighted SN:		67	84	58	(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):		52	63	68	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.