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Daily Report 2023/9/4
[Summary/Forecast]
Solar activity was moderate and it is expected to be moderate on 4 Sep.
Geomagnetic activity in Japan was active level and it is expected to be active level on 4 Sep.
Ionospheric condition over Japan was disturbed and it is expected to be quiet level on 4 Sep.
The geomagnetic storm which started gradually around 6 UT on 2 Sep still continues now.
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[Solar flare]
AR3413 rotated away behind west limb.
Several M-class flares occurred on AR3413 for the past 24 hours.
The largest one was the M6.0 flare that occurred at 08:36 UT on 3 Sep.
Several C-class flares were observed on AR3413 and other regions.
AR3415 will rotate behind west limb.
AR3420 and AR3421 appeared.
Relative sunspot number of AR3417 has decreased.
New active region in the northern hemisphere will appear from east limb in the next 24 hours according to SDO/AIA094.
An M-class flare is expected on AR3413.
Therefore, solar activity is expected to be moderate for the next 24 hours.
- Remarkable flare for the past 3 days
Begin. Max. End. AR#(Loc). XRA/FLA. Solar radio bursts. Related event.
02:54 on 1 Sep 03:51 on 1 Sep 04:47 on 1 Sep 3413 (N14W73) M1.2 II, IV CME
06:33 on 2 Sep 07:12 on 2 Sep 07:38 on 2 Sep 3413 (N10W82) M3.3/SF - CME
00:14 on 3 Sep 00:23 on 3 Sep 00:33 on 3 Sep 3413 (west limb) M1.1 III CME
08:09 on 3 Sep 08:36 on 3 Sep 08:49 on 3 Sep 3413 (west limb) M6.0 III CME
- Today/yesterday active regions (from NOAA)
AR#. Location. Sunspot area. Sunspot num. Class. Magtype.
3415 S09W83 120/120 2/ 2 Cso/Dso beta/ beta
3417 S08W08 40/ 80 4/ 16 Cso/Dsi beta/ beta
3418 N21E10 10/ 10 1/ 1 Hsx/Hsx alpha/alpha
3419 N24W53 10/ 10 3/ 3 Bxo/Bxo beta/ beta
3420 S20E16 30/--- 4/--- Cso/--- beta/ ---
3421 N15E14 20/--- 5/--- Bxo/--- beta/ ---
[Glossary]
- AR: Active Region
[Reference]
- Solar X-ray flux by GOES
https://www.swpc.noaa.gov/products/goes-x-ray-flux
- Solar images taken by STEREO
https://stereo-ssc.nascom.nasa.gov/beacon/beacon_secchi.shtml
- The latest flare list by NOAA/SWPC
https://www.swpc.noaa.gov/products/solar-and-geophysical-event-reports
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[Solar wind/Geomagnetic storm]
The maximum K-index was 4 for the past 24 hours according to Kakioka Magnetic Observatory.
The geomagnetic storm with gradual commencement that occurred around 6 UT on 2 Sep continues now.
The maximum range of H component of geomagnetic field so far is about 101 nT.
The solar wind speed decreased from 530 km/s to 450 km/s.
IMF intensity ranged between 2 nT and 9 nT. IMF Bz occasionally pointed southward and was around -7 nT.
The solar wind density ranged between 6 /cm^3 and 26 /cm^3.
IMF and solar wind disturbances associated with a partial-halo CME that erupted at around 3 UT on 1 Sep can come along, which lead the geomagnetic field to be slightly disturbed.
Therefore, geomagnetic activity in Japan is expected to be active level for the next 24 hours.
[Glossary]
- CME: Coronal Mass Ejection
[Reference]
- Solar wind observation by DSCOVR/ACE
https://www.swpc.noaa.gov/products/real-time-solar-wind
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[Solar proton]
High-energy proton flux (greater than 10 MeV) at geostationary orbit was at low level with the flux of smaller than 1 PFU according to GOES observation.
The proton flux is expected to be below 10 PFU for the next 24 hours.
[Glossary]
- PFU [particles/cm^2/s/sr]: Proton Flux Unit
[Reference]
- High energy proton flux by GOES
https://www.swpc.noaa.gov/products/goes-proton-flux
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[Radiation belt electron]
The 24-hour fluence of electrons (greater than 2 MeV) at geostationary orbit was moderate level (3.89 x 10^7 particles/cm^2/sr) according to GOES.
The electron fluence over the next 24 hours is expected to decrease and become low level because geomagnetic disturbance is expected.
[Glossary]
- Fluence [particles/cm^2/sr]: time integrated value of flux [particles/cm^2/s/sr]
[Reference]
- High energy electron flux by GOES
https://swc.nict.go.jp/trend/electron.html
https://www.swpc.noaa.gov/products/goes-electron-flux
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[Ionospheric storm]
Ionospheric storm detected by using F-layer critical frequency (foF2) is listed as follows.
0-10 UT on 3 Sep. : Low level at Wakkanai.
0-1 UT on 3 Sep. : Low level at Kokubunji.
3-8 UT on 3 Sep. : Low level at Kokubunji.
Ionospheric storm detected by using total electron content (TEC) over Japan is listed as follows.
1-8 UT on 3 Sep. : Low level at 27-47N latitudes.
Quiet ionospheric condition is predicted in the next 24 hours, although active geomagnetic condition is predicted.
[Reference]
- Real-time updates on ionospheric conditions, etc.
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[Short wave fadeout (SWF)/Dellinger phenomenon]
SWF was not observed for the last 24 hours. Moderate probability of SWF occurrence (30-50%) associated with M-class flare for the next 24 hours is predicted.
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[Sporadic-E layer]
Strong sporadic E was observed during the last 24 hours, as listed below.
Wakkanai
3 Sep. 06:00 UT
Kokubunji
3 Sep. 11:15-11:45 UT
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[Shortwave propagation week forecast]
Shortwave propagation week forecast (Announcement day: 9/ 1)
Date: 2 3 4 5 6 7 8
Dellinger phenomenon: 1 1 1 0 0 0 0
Shortwave propagation: 4 4 4 4 4 4 4
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[Solar activity index]
Solar activity indices on September 3
The relative sunspot number (SILSO/ROB) was 94. The average relative sunspot number (SILSO/ROB) in August was 114.9.
The total sunspot area (SWPC/NOAA) was 230. F10.7 (DRAO/NRC) was 130.5.
The sum of geomagnetic K-indices (Kakioka Magnetic Observatory, Japan Meteorological Agency) was 23. The maximum K-index was 4.
Predicted relative sunspot numbers for September, October, and November, used for shortwave propagation prediction, are 154, 160, and 167, respectively.
