:Issued: 2012 Jan 03 1109 UTC
:Product: documentation at http://www.sidc.be/products/bul
#--------------------------------------------------------------------#
# SIDC Weekly bulletin on Solar and Geomagnetic activity #
#--------------------------------------------------------------------#
WEEK 574 from 2011 Dec 26
SOLAR ACTIVITY
--------------
The last week of the year started with flaring at M-level. An M1.5 flare was observed in NOAA AR 11387 (no Catania number), peaking at 02:27 UT on December 26th. This region also produced an M2.3 flare on the same day with peak time 20:30 UT. Also on December 26, a long duration C5.7 flare at 11:50 UT occurred, associated with a filament activation to the northeast of AR 11384. In the following days NOAA ARs 11387 and 11386 produced several C-flares. Starting from December 28, NOAA AR 11389 became the main source of activity. It produced an M1.9 flare at 13:50 UT and an M2.0 flare at 21:51 on December 29, as well as an M1.2 flare at 03:09 on December 30. The same region produced an M2.4 flare on December 31 at 13:15 UT and an M1.5 flare at 16:26 UT.
A filament in the form of an 'O' was present in the northern hemisphere during the week before. It partially erupted on Dec 24 from 23:29UT. Starting from Dec 25, 06:29 UT the remaining part of the filament rose and was ejected. Based on STEREO A/B COR2 data, the speed of the first ejection was estimated between 400 and 500 km/s. The second ejection was less powerful. Since the filament was located near the central meridian, the CME's were Earth-directed. NOAA AR 11387 produced an M4.0 flare on December 25 at 18:16 UT. This eruption was associated with a CME towards the south-west and a proton flux enhancement which did not reach the >10 Mev threshold. The filament activation on December 26 was followed by a CME observed by STEREOa/b COR2 and SOHO/LASCO coronographs. CACTUS estimates the speed of this earth-directed CME around 470 km/s. More CME's were observed during the past week, but these were not Earth-directed.
GEOMAGNETIC ACTIVITY
---------------------
Due to the arrivals of (glancing blows from) the CME's observed on December 25 and 26, we expected unsettled to active geomagnetic conditions starting from December 27th late. Throughout the week, however, geomagnetic conditions have remained very quiet, due to a relatively low solar wind speed and positive southward component of the magnetic field. The southern polar coronal hole had a big extension towards the equator, but no clear disturbance of the solar wind was noticed during this week due to this.
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DAILY INDICES
DATE RC EISN 10CM Ak BKG M X
2011 Dec 26 /// 072 146 000 B6.5 2 0
2011 Dec 27 /// 076 140 000 B5.5 0 0
2011 Dec 28 /// 072 145 004 B5.7 0 0
2011 Dec 29 /// 075 147 010 B6.5 2 0
2011 Dec 30 /// 063 141 008 B5.6 1 0
2011 Dec 31 /// 061 133 007 B3.8 2 0
2012 Jan 01 /// 048 130 005 B4.4 0 0
# RC : Sunspot index (Wolf Number) from Catania Observatory (Italy)
# EISN : Estimated International Sunspot Number
# 10cm : 10.7 cm radioflux (DRAO, Canada)
# Ak : Ak Index Wingst (Germany)
# BKG : Background GOES X-ray level (NOAA, USA)
# M,X : Number of X-ray flares in M and X class, see below (NOAA, USA)
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NOTICEABLE EVENTS
DAY BEGIN MAX END LOC XRAY OP TENCM TYPE Cat NOAA NOTE
26 0213 0227 0236 S21W33 M1.5 1N VI/1 1387
26 2012 2030 2036 S21W42 M2.3 SF III/1 1387
29 1340 1350 1401 M1.9 1389
29 2143 2151 2159 S27E65 M2.0 SF 1389
30 0303 0309 0313 S27E64 M1.2 SN 1389
31 1309 1315 1319 S25E46 M2.4 SF 150 1389
31 1616 1626 1634 S26E42 M1.5 1F 2 1389
#--------------------------------------------------------------------#
# Solar Influences Data analysis Center - RWC Belgium #
# Royal Observatory of Belgium #
# Fax : 32 (0) 2 373 0 224 #
# Tel.: 32 (0) 2 373 0 491 #
#--------------------------------------------------------------------#
:Product: documentation at http://www.sidc.be/products/bul
#--------------------------------------------------------------------#
# SIDC Weekly bulletin on Solar and Geomagnetic activity #
#--------------------------------------------------------------------#
WEEK 574 from 2011 Dec 26
SOLAR ACTIVITY
--------------
The last week of the year started with flaring at M-level. An M1.5 flare was observed in NOAA AR 11387 (no Catania number), peaking at 02:27 UT on December 26th. This region also produced an M2.3 flare on the same day with peak time 20:30 UT. Also on December 26, a long duration C5.7 flare at 11:50 UT occurred, associated with a filament activation to the northeast of AR 11384. In the following days NOAA ARs 11387 and 11386 produced several C-flares. Starting from December 28, NOAA AR 11389 became the main source of activity. It produced an M1.9 flare at 13:50 UT and an M2.0 flare at 21:51 on December 29, as well as an M1.2 flare at 03:09 on December 30. The same region produced an M2.4 flare on December 31 at 13:15 UT and an M1.5 flare at 16:26 UT.
A filament in the form of an 'O' was present in the northern hemisphere during the week before. It partially erupted on Dec 24 from 23:29UT. Starting from Dec 25, 06:29 UT the remaining part of the filament rose and was ejected. Based on STEREO A/B COR2 data, the speed of the first ejection was estimated between 400 and 500 km/s. The second ejection was less powerful. Since the filament was located near the central meridian, the CME's were Earth-directed. NOAA AR 11387 produced an M4.0 flare on December 25 at 18:16 UT. This eruption was associated with a CME towards the south-west and a proton flux enhancement which did not reach the >10 Mev threshold. The filament activation on December 26 was followed by a CME observed by STEREOa/b COR2 and SOHO/LASCO coronographs. CACTUS estimates the speed of this earth-directed CME around 470 km/s. More CME's were observed during the past week, but these were not Earth-directed.
GEOMAGNETIC ACTIVITY
---------------------
Due to the arrivals of (glancing blows from) the CME's observed on December 25 and 26, we expected unsettled to active geomagnetic conditions starting from December 27th late. Throughout the week, however, geomagnetic conditions have remained very quiet, due to a relatively low solar wind speed and positive southward component of the magnetic field. The southern polar coronal hole had a big extension towards the equator, but no clear disturbance of the solar wind was noticed during this week due to this.
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DAILY INDICES
DATE RC EISN 10CM Ak BKG M X
2011 Dec 26 /// 072 146 000 B6.5 2 0
2011 Dec 27 /// 076 140 000 B5.5 0 0
2011 Dec 28 /// 072 145 004 B5.7 0 0
2011 Dec 29 /// 075 147 010 B6.5 2 0
2011 Dec 30 /// 063 141 008 B5.6 1 0
2011 Dec 31 /// 061 133 007 B3.8 2 0
2012 Jan 01 /// 048 130 005 B4.4 0 0
# RC : Sunspot index (Wolf Number) from Catania Observatory (Italy)
# EISN : Estimated International Sunspot Number
# 10cm : 10.7 cm radioflux (DRAO, Canada)
# Ak : Ak Index Wingst (Germany)
# BKG : Background GOES X-ray level (NOAA, USA)
# M,X : Number of X-ray flares in M and X class, see below (NOAA, USA)
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NOTICEABLE EVENTS
DAY BEGIN MAX END LOC XRAY OP TENCM TYPE Cat NOAA NOTE
26 0213 0227 0236 S21W33 M1.5 1N VI/1 1387
26 2012 2030 2036 S21W42 M2.3 SF III/1 1387
29 1340 1350 1401 M1.9 1389
29 2143 2151 2159 S27E65 M2.0 SF 1389
30 0303 0309 0313 S27E64 M1.2 SN 1389
31 1309 1315 1319 S25E46 M2.4 SF 150 1389
31 1616 1626 1634 S26E42 M1.5 1F 2 1389
#--------------------------------------------------------------------#
# Solar Influences Data analysis Center - RWC Belgium #
# Royal Observatory of Belgium #
# Fax : 32 (0) 2 373 0 224 #
# Tel.: 32 (0) 2 373 0 491 #
#--------------------------------------------------------------------#