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- DAILY SUMMARY OF SOLAR GEOPHYSICAL ACTIVITY
-
- 08 SEPTEMBER, 1991
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- (Based In-Part On SESC Observational Data)
-
-
- SOLAR AND GEOPHYSICAL ACTIVITY INDICES FOR 08 SEPTEMBER
- -------------------------------------------------------
-
- !!BEGIN!! (1.0) S.T.D. Solar Geophysical Data Broadcast for DAY 251, 09/08/91
- 10.7 FLUX=196.1 90-AVG=204 SSN=194 BKI=4434 3333 BAI=019
- BGND-XRAY=C3.2 FLU1=1.6E+06 FLU10=1.3E+04 PKI=4324 4443 PAI=023
- BOU-DEV=052,057,030,051,036,037,029,022 DEV-AVG=039 NT SWF=06:177
- XRAY-MAX= X1.0 @ 0912UT XRAY-MIN= C2.6 @ 1524UT XRAY-AVG= C7.2
- NEUTN-MAX= +005% @ 2110UT NEUTN-MIN= +000% @ 2225UT NEUTN-AVG= +1.8%
- PCA-MAX= +0.1DB @ 0305UT PCA-MIN= -0.8DB @ 2015UT PCA-AVG= -0.1DB
- BOUTF-MAX=55324NT @ 2314UT BOUTF-MIN=55244NT @ 1753UT BOUTF-AVG=55299NT
- GOES7-MAX=P:+125NT@ 1727UT GOES7-MIN=N:-029NT@ 1014UT G7-AVG=+071,+057,+002
- GOES6-MAX=P:+125NT@ 2145UT GOES6-MIN=N:-014NT@ 1307UT G6-AVG=+076,+023,+013
- FLUXFCST=STD:218,225,230;SESC:210,210,205 BAI/PAI-FCST=020,030,030/035,050,075
- KFCST=4445 5444 4445 5444 28DAY-AP=052,018 28DAY-KP=2555 5665 4243 4322
- WARNINGS=*MAJFLR;*PROTON;*PCA;*GSTRM;*AURMIDWRN;*AURLOWWCH
- ALERTS=**MAJFLR:X1.0/2N,S11W50(6818),0905-0912-0935,II=2@0919,IV=1@0946;
- **TENFLR:390SFU@0907,DUR=11;**MINFLR:M2.1@0154;**MINFLR:M1.0@0818;
- **MINFLR:M1.1@0831;**MINFLR:M2.7@1144;**MINFLR:M1.6@2044
- !!END-DATA!!
-
-
- BRIEF SUMMARY OF EVENTS
- -----------------------
-
- The highlight of the day was a class X1.0/2N tenflare at 09:12 UT that
- was accompanied by minor radio emissions. Of the emissions observed, an
- impressive Type II sweep was observed. Although this Type II did not have a
- particularly strong radio signature, the speed of the estimated disturbance
- propagating outward was an impressive 1,000 kilometers per second. A weak
- Type IV sweep frequency event was also observed at 09:46 UT. Overall, this
- major flare was not particularly impressive, given its size. The duration of
- the flare was a rather impulsive 30 minutes.
-
- Region 6818 (S12W65) which spawned this major event, continued to
- exhibit growth and increased in magnetic complexity during the UT day. It is
- now a beta-gamma-delta magnetic group with the delta occurring in the leader
- spot complex. This corresponds to the hottest plage area observed in the
- region.
-
- The only optically uncorrelated M-class flare occurred at 20:44 UT. A
- likely source lies just beyond the east limb with the complex of regions
- (6781, 6782, 6786 and 6795) which are due to return over the next 24 hours.
- Region 6786 previously produced 5 M-class events on its last rotation, but
- was rather small in size when it departed the west limb about two weeks ago.
-
- Two new regions were numbered today. Region 6823 (N03E17) rapidly
- developed today and spawned several high-level C-class flares. The other
- active region numbered today was Region 6824 (S21E71) which rotated into view
- and produced some surge activity.
-
- Further major flaring from Region 6818 is possible. M-class flaring
- will also continue.
-
- Geomagnetic activity today was unsettled to active. Conditions on 09
- September should be mostly active with a few possible periods of minor
- storming over the higher latitudes. On 10 September, activity is expected
- to increase to minor storm levels. By 11 September, minor to major storming
- is possible. The combined effects of a well placed coronal hole, several
- disappearing solar filaments on 05 September, and the recent major X-class
- flares are expected to be responsible for the increased activity levels.
-
- Auroral activity warnings and watches have been issued for the middle
- and low latitudes respectively. A respectable amount of auroral activity is
- expected to accompany this activity. High to northerly middle latitudes
- should witness the most energetic activity. However, the accompanying
- luminosity should be sufficient to be observed over the middle to possibly
- the lower latitudes. Activity is expected to peak on 10 or 11 September.
- Lunar phase will not interfere with observations.
-
- HF signals will become degraded over the high and middle latitude
- regions. Degradation will be greatest during the local evening and early
- morning hours. A fairly significant amount of auroral flutter, fading and
- noise can be expected over these regions. Low latitudes can expect mostly
- good to fair propagation conditions, but with notable flutter and fading from
- signals traversing the higher latitude paths.
-
- VHF auroral backscatter will become a definite possibility over the
- middle latitudes if this disturbance reaches forecasted levels of activity.
-
-
- ** End of Daily Update **
-