mercoledì 22 dicembre 2010

SIDC Weekly Bulletin

:Issued: 2010 Dec 21 0853 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 520 from 2010 Dec 13 

SOLAR ACTIVITY
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The strongest solar event in this period was a C5.3 flare from active region NOAA 11135 on Dec 15.
Other noteworthy activity was a long duration C2.3 flare on Dec 14 from NOAA 11134.

>From Dec 15-16 onwards, the complex of NOAA active regions 11131, 11133 and 11134 in the
Northern solar hemisphere rotated behind the solar limb, resulting in a downward trend in all
solar indices (F10.7, GOES X-ray curves and the LYRA and SWAP curves).

An SIDC all quiet alert was issued from Saterday Dec 18 onwards.

GEOMAGNETIC ACTIVITY
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Geomagnetic activity was low this week and characterized by the passage of a high speed solar wind
stream. The solar wind started the period at about 400 km/s and went up over 600 km/s on Dec 14.
After that, a gradual decrease was observed down to again 400 km/s by the end of the period.

Geomagnetic activity was strongest on Dec 14 and early Dec 15 with up to 1 episode of K=4. For the
rest of the period geomagnetic activity was typically at K=2 levels.

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DAILY INDICES
DATE          RC  EISN  10CM  Ak  BKG    M  X
2010 Dec 13  048    026  88  010  B1.1  0  0
2010 Dec 14  033    015  90  019  B1.0  0  0
2010 Dec 15  ///    008  87  010  A9.9  0  0
2010 Dec 16  023    015  84  008  A8.9  0  0
2010 Dec 17  011    007  82  006  A6.7  0  0
2010 Dec 18  011    000  81  003  A5.1  0  0
2010 Dec 19  ///    000  81  004  A4.3  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


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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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