mercoledì 23 marzo 2011

SIDC Weekly Bulletin

:Issued: 2011 Mar 22 1303 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 533 from 2011 Mar 14 

SOLAR ACTIVITY
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The solar activity was high in the beginning of the week, mainly due to Catania sunspot groups 22 and 26 (NOAA ARs 1166 and 1169). These sunspot groups produced numerous C-class flares on March 14-16. Catania sunspot group 26 (NOAA AR 1169) produced two M-class flares (M4.2 and M1.0 on March 14 and 15 respectively). The CMEs associated with these flares were not directed to the Earth. Further on, the flaring activity of the Sun decreased. The solar X-ray background flux decreased, and no flaring activity above the C-level was detected during March 17-20. On March 20, the solar X-ray background flux started to grow due to a returning active region at the south-east limb (NOAA AR 1165 during the previous rotation).

A partial halo CME was first detected in the LASCO C2 field of view at 12:48 UT on March 17. According to STEREO/SECCHI data, it was originating on the far side of the Sun, therefore, it had no geomagnetic consequences.

GEOMAGNETIC ACTIVITY
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After the period of elevated solar wind speed on March 14 and early on March 15, the Earth entered the slow solar wind flow, where it stayed until the end of the week. The geomagnetic conditions were quiet throughout the whole week.

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DAILY INDICES
DATE          RC  EISN  10CM  Ak  BKG    M  X
2011 Mar 14  ///    035  107  002  B3.8  1  0
2011 Mar 15  056    029  102  002  B3.5  1  0
2011 Mar 16  023    022  95  002  B2.9  0  0
2011 Mar 17  ///    025  90  006  B2.5  0  0
2011 Mar 18  052    016  88  003  B1.4  0  0
2011 Mar 19  054    018  89  004  B1.2  0  0
2011 Mar 20  ///    020  92  008  B2.2  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
14  1930  1952 1954 N18W48 M4.2 1N                                  26  1169
15  0018  0022 0024        M1.0                                    26  1169


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# 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                                          #
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