home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Shareware Overload
/
ShartewareOverload.cdr
/
database
/
bcast100.zip
/
SGDBS.ZIP
/
91-10-28.DLY
< prev
next >
Wrap
Text File
|
1991-10-28
|
7KB
|
120 lines
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
DAILY SUMMARY OF SOLAR GEOPHYSICAL ACTIVITY
28 OCTOBER, 1991
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
(Based In-Part On SESC Observational Data)
SOLAR AND GEOPHYSICAL ACTIVITY INDICES FOR 28 OCTOBER
-----------------------------------------------------
!!BEGIN!! (1.0) S.T.D. Solar Geophysical Data Broadcast for DAY 301, 10/28/91
10.7 FLUX=271.0 90-AVG=196 SSN=307 BKI=5545 7954 BAI=098
BGND-XRAY=C2.6 FLU1=*.*E*** FLU10=3.8E+05 PKI=4556 7854 PAI=086
BOU-DEV=085,099,049,101,209,528,093,042 DEV-AVG=150 NT SWF=07:089
XRAY-MAX= M2.2 @ 1748UT XRAY-MIN= C2.0 @ 2338UT XRAY-AVG= C4.6
NEUTN-MAX= +003% @ 0810UT NEUTN-MIN= -015% @ 2320UT NEUTN-AVG= -4.0%
PCA-MAX= +2.3DB @ 1610UT PCA-MIN= -0.1DB @ 0755UT PCA-AVG= +0.4DB
BOUTF-MAX=55330NT @ 0334UT BOUTF-MIN=55093NT @ 1539UT BOUTF-AVG=55274NT
GOES7-MAX=P:+243NT@ 1759UT GOES7-MIN=N:-208NT@ 1552UT G7-AVG=+076,+053,+016
GOES6-MAX=P:+289NT@ 1606UT GOES6-MIN=P:-083NT@ 1538UT G6-AVG=+102,+000,+031
FLUXFCST=STD:255,245,240;SESC:275,265,255 BAI/PAI-FCST=068,047,030/060,045,030
KFCST=7776 6556 7676 5555 27DAY-AP=046,018 27DAY-KP=5556 5543 3434 3322
WARNINGS=*MAJFLR;*PROTFLR;*PROTON;*PCA;*GSTRM;*AURMIDWRN;*AURLOWWRN
ALERTS=**MINFLR:M1.1@0112;**MINFLR:M1.5@0743;**MINFLR:M2.1@1240;
**MINFLR:M1.0@1529;**MINFLR:M1.3@1619;**MINFLR:M2.2@1749;
**MINFLR:M1.3@2030;**MAGSI:50NT@1054;**245STRM:0000-2400UT;
**TENFLR:260SFU@1230;**MAJSTRM;**PROTN10:40PFU@1440;
**PCA:2.2DB@1530;**FORBUSH:BEGAN@0900
!!END-DATA!!
BRIEF SUMMARY OF EVENTS
-----------------------
Solar activity was high today by virtue of seven minor M-class flares
which erupted out of Region 6891 (S12W06). Region 6891 dissipated most of
its pent-up energy in the form of these frequent M-class events. The largest
event was an M2.2/1N at 17:49 UT. Also of interest was an optically
uncorrelated class M2.1 x-ray event which was observed at 12:40 UT and was
associated with a tenflare of 260 sfu.
Region 6891 exhibited a minor amount of decay today, particularly in the
penumbral area of this region. However, it remains extremely potent and
complex. It is still very capable of producing significant major energetic
events, and may do so again over the next 72 hours should minor flaring
abate.
Region 6892 (S20W06) was also eruptive today, spawning several minor
flares in tandem with Region 6891. Two new regions were assigned today:
Region 6898 (S07W26) and 6899 (S12E39).
Solar activity should continue moderate to high. Region 6891 is
expected to continue to generate minor and/or major solar flares. There is
a 50% probability for a major X-class proton flare over the next 24 to 72
hours. A moderate to high risk for renewed proton and PCA activity exists
over the next week.
A major to severe geomagnetic storm commenced at 10:54 UT with the
arrival of an interplanetary shockwave. The associated sudden magnetic
impulse measured 54 nT at Boulder. Other stations reported similar values
near 50 nT. Geomagnetic activity rapidly intensified to major storm levels.
This event is thought to have been generated possibly by one of the first
energetic flares from Region 6891, perhaps the long duration M1 with an
impressively long Type IV sweep on 26 October. At 15:37 UT, the field
experienced another jolt which pushed K-indices for most middle latitude
regions to values of 8 and 9 (nine is the top of the scale). During the
local afternoon hours, conditions quieted somewhat with frequent magnetic
pulsations observed almost continuously throughout the period.
Geomagnetic activity is expected to remain at major to severe storm
levels throughout the next 12 to 24 hours. Impacts from the other major
solar flares probably have not arrived yet. If and when they arrive, the
field may become further disturbed. This major geomagnetic storm is not
expected to end until approximately 01 November (barring further major
energetic events).
Auroral storming commenced with the arrival of the interplanetary
shockwave discussed above. High levels of activity were observed primarily
over the high and northerly middle latitude regions. Equatorward expansion
of the auroral oval has taken place. High levels of activity are anticipated
for the middle and high latitude regions. As of this writing (03:30 UT),
significant auroral and geomagnetic storming is being observed over most
middle latitude regions. It is too early to determine whether low-latitude
sites are observing activity. A warning has been issued for low latitude
auroral observations. Conditions remain favorable for low latitude auroral
activity.
A strong Forbush decrease of approximately 10 percent (with a brief
excursion to 15 percent) has been observed by the polar neutron monitors. As
of this writing, neutron counts are still near 10 percent. The event began
near 09:00 UT and is expected to continue for at least the next 24 to 48
hours.
A brief satellite proton and PCA event began at 13:00 UT and 15:30 UT
respectively. Both have since abated and are now running near background
levels. The proton event briefly reached a peak flux of 40 pfu at greater
than 10 MeV, while the PCA event briefly reached a level of 2.2 dB.
HF propagation conditions have been significantly degraded since the
arrival of this disturbance. Most regions have reported only fair to poor
propagation conditions, although numerous low latitude regions reported good
to fair conditions during the daylight hours. Conditions will be worst
during the local evening and early morning hours. Significant middle
latitude ionospheric storming could produce temporary blackout conditions.
Overall, middle and high latitude activity should range from fair (over the
middle latitudes during the daylight hours) to blackout or near blackout
conditions (over the high latitude regions during the local night sector).
This disturbance will continue for at least the next 48 to 72 hours. During
this period, the intensity of the disturbance should gradually decline. Low
and middle latitude regions will notice improvements first, followed by the
high and polar latitude regions. Further major energetic flaring could
prolong or renew degraded conditions later this week.
** End of Daily Update **