SIDC Weekly Bulletin

:Issued: 2013 May 22 1519 UTC
:Product: documentation at http://www.sidc.be/products/bul
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# SIDC Weekly bulletin on Solar and Geomagnetic activity             #
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WEEK 646 from 2013 May 12
SOLAR ACTIVITY
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Solar activity was dominated by NOAA AR 1748 (with beta-gamma-delta
configuration most of the week), that produced several M-class flares and
four X-class flares. The first one occurred while the AR was still behind
the east limb on May 13 at 02:17 UT. The next one was an X2.8 with peak at
16:05 UT on May 13. The third one an X3.2 at 01:11 UT on May 14. Finally,
the fourth X-class flare occurred on May 15, it was an X1.2 solar flare
peaking at 01:48 UT. All four flares were associated with radio bursts and
fast limb CMEs. The proton flux threshold of 10 protons/cm2-s-sr was
crossed on May 15, and stayed slightly above it for 4 days. On May 17, a
CME erupted in relation with an M3.2 flare from NOAA AR 1748, at 08:57 UT.
GEOMAGNETIC ACTIVITY
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A CME from May 12 arrived to the Earth with weak signatures on May 15,
producing active geomagnetic conditions (otherwise quiet to unsettled
levels were seen in the beginning of the week). A shock arrived to the
Earth at 00:30 UT on May 18, it corresponded to the CME from May 15, it
caused Kp = 5, between 00:00 UT and 06:00UT, while the local Dourbes K
value went up to 4. The CME from May 17 arrived to the Earth on May 19 at
22:23 UT and produced active geomagnetic conditions.
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DAILY INDICES
DATE           RC   EISN  10CM   Ak   BKG    M   X
2013 May 12   ///    021   147   006   B8.5   2   0   
2013 May 13   147    015   150   006   C1.1   1   3   
2013 May 14   176    020   148   009   B7.1   0   1   
2013 May 15   ///    027   146   011   B7.7   0   1   
2013 May 16   ///    018   145   024   B6.0   1   0   
2013 May 17   200    014   136   012   B5.7   1   0   
2013 May 18   ///    016   132   019   B4.8   0   0   
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# 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 SUMMARY
DAY BEGIN MAX  END  LOC    XRAY OP  10CM RADIO BURST TYPES     Catania NOAA
12  2017  2032 2103 ////// M1.9     III/2                      1748
12  2237  2244 2252 ////// M1.2     1748
13  0153  0217 0232 ////// X1.7     III/2VII/3II/1CTM/1        1748
13  1157  1203 1209 ////// M1.3     1748
13  1548  1605 1616 N11E85 X2.8 1N  II/2IV/2                   1748
13  2359  0111 0120 ////// X3.2     1748
14  0000  0111 0120 ////// X3.2     II/1IV/1III/3              1748
15  0125  0148 0158 N12E64 X1.2 2N  IV/2II/1                   1748
16  2136  2153 2203 N13E41 M1.3 1N  III/1                      1748
17  0843  0857 0919 N12E57 M3.2 2B  IV/2II/2                   1748
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