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: 2023 Mar 20 1745 UTC :Product: documentation at http://www.sidc.be/products/bul #--------------------------------------------------------------------# # SIDC Weekly bulletin on Solar and Geomagnetic activity # #--------------------------------------------------------------------# WEEK 1159 from 2023 Mar 13 SOLAR ACTIVITY --------------- Over the past week the solar flaring activity was at low levels. There were fifteen numbered active regions on the visible disk. They all had relatively simple alpha or beta magnetic field configuration and produced 23 C-class flares and 1 M-class flare. The largest flare over a week was a M1.1 flare, peaking at 15:07 UTC on March 17, associated with NOAA AR3254. The second largest flare was an impulsive C9.4 flare at 07:10 UTC on March 18, produced by NOAA active region 3256. This event was also associated with Type IV radio emission. Two small equatorial coronal holes of positive polarity were visible in the week. The first one transited the central meridian on March 11 and the second one on March 16. A filament eruption in the southeastern quadrant was observed on March 12 around 17:45UTC. The associated CME appeared in SoHO/LASCO C2 coronagraph data from 19:00UTC onwards. The CME was directed to the south and the bulk of the CME was not expected to be Earth directed. However, a glancing blow of the shock was predicted to impact Earth on March 15. Indeed, shock was observed in the solar wind early on March 15, that might be associated to the CME. A full halo CME was seen in LASCO C2 imagery from 03:36 UTC on March 13. This was determined to be a back-sided event and was not expected to arrive to Earth. However, the greater than 10 MeV proton flux levels have been elevated related to this event, reaching minor radiation storm levels. A filament eruption occurred in the northern hemisphere near disc center at around 09:50UTC on March 13. The associated CME, that appears in SoHO/LASCO C2 coronagraph data from 10:48UTC onwards, was directed to the north-west. The bulk of this eruptions was estimated to miss Earth, but there was a chance for a glancing blow early on March 16. However, this was not observed in the in-situ solar wind data. Another filament eruption in the southwestern quadrant was observed on March 17 from around 09:20UTC. The associated CME appears in SoHO/LASCO C2 coronagraph data from 10:23UTC onwards. The CME was directed to the south-west and the bulk of the CME was not expected to be Earth directed, but there was a chance, that a glancing blow of the shock may impact Earth late on on March 19. The greater than 10 MeV proton flux was at nominal levels at the start of the week and got elevated on March 13 following backsided full halo CME, crossing the 10pfu event threshold around 07:45UTC on March 13. The greater than 10 MeV proton flux has reached the maximum value of 22pfu at around 04:25UTC on March 15 and returned to near the nominal levels from around 16:00UTC on March 15. The greater than 2 MeV electron flux was below the 1000 pfu threshold throughout the week. The 24h electron fluence was at normal levels throughout the week. GEOMAGNETIC ACTIVITY --------------------- The solar wind parameters have been indicative of slow solar wind conditions at the start of the week. The solar wind speed showed a gradually decreasing trend, decreasing from 380 km/s to values around 320 km/s. The orientation of the magnetic field was predominantly in the negative sector (field directed towards the Sun) with a variable north-south component Bz ranging between 0 to 6 nT. A high-speed stream from a positive polarity equatorial coronal hole began to influence the Earth from March 14. The solar wind conditions became slightly disturbed with the total interplanetary magnetic field rose to 15 nT at around 04:30UTC on March 14. The north-south component of the magnetic field was variable, ranging between -11 to 13 nT. The solar wind velocity followed an increasing trend, rising from 320 km/s to 410 km/s. The orientation of the magnetic field showed a switch from the negative (field towards the Sun) to positive sector (field away from the Sun). On March 15, around 03:39UTC a shock was observed with solar wind speed jumping from 410 km/s to 550 km/s and the total interplanetary magnetic field jumping from 8 nT to 24 nT. The shock might be associated to the CME that left the Sun on 19:00UTC, March 12. Towards the end of the week, the solar wind speed gradually decreased to values near 420 km/s. The geomagnetic conditions were at quiet to unsettled levels at the start of the week, increasing to active on March 14 – March 16 due to the ICME and high speed steam influences with isolated moderate storm period globally (NOAA- Kp = 6-) and minor storm period locally (K Bel = 5) at around 03:00 UTC and 21:00 UTC on March 15. Conditions then returned to quiet to unsettled levels for the rest of the week. --------------------------------------------------------------------------- DAILY INDICES DATE RC EISN 10CM Ak BKG M X 2023 Mar 13 101 104 143 003 B5.6 0 0 2023 Mar 14 122 111 139 018 B5.9 0 0 2023 Mar 15 135 106 136 028 B5.6 0 0 2023 Mar 16 110 096 135 007 B6.1 0 0 2023 Mar 17 110 071 134 007 B8.4 1 0 2023 Mar 18 /// 044 140 010 B8.7 0 0 2023 Mar 19 /// 074 143 014 B9.5 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 17 1504 1507 1511 S22W65 M1.0 SN 12/3247 #--------------------------------------------------------------------# # 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 # #--------------------------------------------------------------------#
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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.