SIDC Weekly Bulletin

Issued: 2020 Sep 14 1259 UTC
Product: documentation at www.sidc.be/products/bul
#——————————————————————–#

SIDC Weekly bulletin on Solar and Geomagnetic activity #

#——————————————————————–#
WEEK 1028 from 2020 Sep 07
SOLAR ACTIVITY
—————
Solar activity was at very low levels. The Sun was spotless for the entire week. The daily 10.7cm solar radio flux ranged between 68.7 and 70.2 sfu. No earth-directed coronal mass ejections (CMEs) were observed. CME activity from the Sun’s west limb was observed late on 7 and on 8 September, most likely related to activity just behind the west limb (no obvious on-disk source). A narrow extension from the negative polarity southern polar coronal hole (CH) transited the central meridian on 10 September. A small and diffuse negative polarity equatorial CH was near disk center on 13-14 September. The greater than 10 MeV proton flux was at nominal values.
GEOMAGNETIC ACTIVITY
———————
Solar wind parameters were at nominal levels. Solar wind speed decreased from values near 400 km/s to a minimum near 270 km/s on 10 September, then varying between mostly 300-350 km/s. Bz varied between -5 and +6 nT. Two sector boundary crossings were observed, resp. on 8 and on 11 September. The direction of the interplanetary magnetic field was in a predominantly positive sector (away from the Sun) until 8 September, then switched to a negative sector until 11 September, when it switched back to a positive sector. A small disturbance arrived just before the end of the period, driving Bz to -8 nT, and resulting in mostly unsettled intervals. Geomagnetic activity was at mostly quiet levels, with isolated unsettled intervals recorded in both Kp and K Dourbes. The greater than 2 MeV electron flux ranged from High (10.200 pfu on 7 September) to Moderate levels, its daily maximum exceeding the 1000 pfu alert threshold every day of the week.
—————————————————————————
DAILY INDICES
DATE RC EISN 10CM Ak BKG M X
2020 Sep 07 /// 000 070 004 A1.1 0 0
2020 Sep 08 /// 000 070 004 A1.1 0 0
2020 Sep 09 000 000 070 001 //// 0 0
2020 Sep 10 000 000 069 002 //// 0 0
2020 Sep 11 000 000 069 003 //// 0 0
2020 Sep 12 /// 000 069 006 //// 0 0
2020 Sep 13 /// 000 070 008 //// 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

#——————————————————————–#

– #

#

#

Website www.sidc.be. #

E-mail #

To unsubscribe #

#

#

– Intellectual Property Rights: #

#

– Liability Disclaimer: #

#

– Use and processing of your personal information: #

#

#——————————————————————–#