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 |
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:Issued: 2021 Apr 19 1457 UTC :Product: documentation at http://www.sidc.be/products/bul #--------------------------------------------------------------------# # SIDC Weekly bulletin on Solar and Geomagnetic activity # #--------------------------------------------------------------------# WEEK 1059 from 2021 Apr 12 SOLAR ACTIVITY --------------- The solar activity was at very low levels over the entire week. There were in total 3 active regions on the solar disk, namely NOAA AR 2814 (Catania 87), AR 2815 and AR 2816. All of them exhibited bipolar magnetic field and were classifies as magnetic type Beta. The flaring activity remained below C-class flare level throughout the entire week. The highest activity registered was a B9.7 class flare originating from behind the east limb (S21E88) on April 17th with a peak time 17:17 UTC. This flare was associated with a back-sided CME and a type II radio emission. No Earth-directed Coronal Mass Ejections (CMEs) were detected in the available chronograph imagery for the entire week. The greater than 10 MeV proton flux remained at background levels over the entire week. The greater than 2 MeV electron flux crosses the 1000 pfu threshold on April 17th and registered prolonged period with values above 10000 on April 18th. The electron fluence was at nominal levels until April 18th when moderate levels were reached. GEOMAGNETIC ACTIVITY --------------------- The solar wind parameters (based on DSCOVR and ACE data) reflected a slow solar wind regime until April 15th, when a drop of the temperature, increase in the magnetic field and density, and some increase in the solar wind speed suggested the arrival of an ICME at Earth. The source for the ICME was identified as a coronal mass ejection setting off the west solar limb in the UTC morning of April 10th. On April 16th enhancements in the solar wind speed, temperature and magnetic field values were registered with the mixed arrival of two high speed streams (HSSs) emanating from a small equatorial negative-polarity coronal hole and from a high-latitude extension of the souther polar coronal hole (with negative polarity as well). Enhanced solar wind speed and temperature prevailed throughout the rest of the week with registered high solar wind velocity of up to 668 km/s. The geomagnetic conditions were mostly quiet until April 15th, when the ICME arrival caused an isolated period of minor geomagnetic storm based on the global NOAA Kp index between 21:00 UTC on April 14th and 00:00 UTC on April 15th. Locally in Dourbes only active conditions were detected on that day. From 18:00 UTC on April 16th throughout 09:00 UTC on April 17th the arrival of the HSSs resulted in multiple periods with minor geomagnetic storm levels, as registered by NOAA Kp and K Dourbes indices. Mostly active to unsettled conditions prevailed throughout the rest of the week. --------------------------------------------------------------------------- DAILY INDICES DATE RC EISN 10CM Ak BKG M X 2021 Apr 12 /// 016 083 006 A2.7 0 0 2021 Apr 13 024 019 073 006 A2.5 0 0 2021 Apr 14 021 020 074 008 A3.7 0 0 2021 Apr 15 /// 025 072 014 A4.7 0 0 2021 Apr 16 /// 037 077 020 A4.8 0 0 2021 Apr 17 /// 018 075 031 A4.4 0 0 2021 Apr 18 /// 017 078 020 A7.4 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) --------------------------------------------------------------------------- NOTICEABLE EVENTS SUMMARY DAY BEGIN MAX END LOC XRAY OP 10CM Catania/NOAA RADIO_BURST_TYPES NONE #--------------------------------------------------------------------# # Solar Influences Data analysis Center - RWC Belgium # # Royal Observatory of Belgium # # # # Website http://www.sidc.be. # # E-mail sidc-support@oma.be # # To unsubscribe http://www.sidc.be/registration/unsub.php # # # # Legal notices: # # - Intellectual Property Rights: # # http://www.astro.oma.be/common/internet/en/data-policy-en.pdf # # - Liability Disclaimer: # # http://www.astro.oma.be/common/internet/en/disclaimer-en.pdf # # - Use and processing of your personal information: # # http://www.astro.oma.be/common/internet/en/privacy-policy-en.pdf # #--------------------------------------------------------------------#
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.