SIDC Weekly Bulletin

Review of past solar and geomagnetic activity.
Source SIDC (RWC-Belgium)
Frequency Weekly
Format Plain text
Mail header SIDC Weekly Bulletin
SIDC code bul

Archive

Latest issue

:Issued: 2019 Aug 12 1358 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 971 from 2019 Aug 05
SOLAR ACTIVITY
---------------
Solar activity was at very low levels. Two small sunspot groups were
visible on resp. 5-6 (NOAA 2746) and 6-7 (NOAA 2747) August. Both groups
belonged to the old solar cycle 24 and were inactive, though a small
eruption was observed on 7 August in NOAA 2746 when the region was already
spotless. On 4 August, a filament eruption took place at N45W50 close to
the northern polar coronal. The associated coronal mass ejection (CME) was
not directed to Earth. No earth-directed CMEs were observed during the
week. The greater than 10 MeV proton flux was at nominal levels. A positive
polarity equatorial coronal hole (CH) rotated over the west limb around 8
August, whereas a diffuse and patchy negative polarity CH transited the
central meridian (CM) on 7 August.
GEOMAGNETIC ACTIVITY
---------------------
The co-rotating interaction region (CIR) and high speed wind stream (HSS)
from the positive polarity coronal hole (CH) arrived on 5 August. Wind
speeds reached maximum values between 700 and 760 km/s on 5-6 August (ACE),
the highest in more than a year. Wind speeds then gradually decreased to
400 km/s by the end of the period, however with some pronounced
enhancements on 8 and 9-10 August, when values increased back to resp. 570
and 660 km/s. Bz reached -21 nT during the passage of the CIR, then varied
between -6 and +5 nT for the rest of the week. The Interplanetary Magnetic
Field (IMF) was predominately directed away from the Sun (positive sector).
By the end of the period, the wind stream of the negative polarity CH had
not arrived yet.   

The passage of the CIR and HSS of the positive polarity CH resulted in a
minor geomagnetic storm. Kp remained at 5 (minor storm) for 4 consecutive
3-hour intervals, and also in Dourbes the K index reached 5. From 6 August
onwards, geomagnetic activity was at quiet to unsettled levels with K
Dourbes recording an isolated active episode during the 23-02UT interval on
9-10 August.
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DAILY INDICES
DATE           RC   EISN  10CM   Ak   BKG    M   X
2019 Aug 05   ///    013   068   035   A6.5   0   0   
2019 Aug 06   ///    000   068   013   A7.0   0   0   
2019 Aug 07   ///    007   068   008   A7.0   0   0   
2019 Aug 08   ///    000   069   008   A6.9   0   0   
2019 Aug 09   ///    000   067   008   A6.8   0   0   
2019 Aug 10   ///    000   067   010   A6.5   0   0   
2019 Aug 11   ///    000   068   008   A6.5   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 Catania/NOAA RADIO_BURST_TYPES 
NONE
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Details

This report is sent once a week, typically on a monday.
The weekly bulletin gives an overview of solar and geomagnetic activity of the past week and includes a noticeable solar events list.
Check the ISES code book for information on ISES codes.