From: oler@rho.uleth.ca (Cary Oler)
Subject: Daily Summary of Solar Geophysical Activity for 11 September
Apparently-To: sci-space-news@ames.arc.nasa.gov
Followup-To: sci.space
Organization: University of Lethbridge
Date: Sat, 12 Sep 1992 03:01:23 GMT

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                 DAILY SUMMARY OF SOLAR GEOPHYSICAL ACTIVITY

                              11 SEPTEMBER, 1992

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                  (Based In-Part On SESC Observational Data)


SOLAR AND GEOPHYSICAL ACTIVITY INDICES FOR 11 SEPTEMBER
-------------------------------------------------------

!!BEGIN!! (1.0) S.T.D. Solar Geophysical Data Broadcast for DAY 255, 09/11/92
10.7 FLUX=118.6  90-AVG=124        SSN=090      BKI=5462 2321  BAI=024
BGND-XRAY=B3.1     FLU1=1.1E+06  FLU10=1.2E+04  PKI=6564 4433  PAI=035
  BOU-DEV=112,059,122,018,019,033,012,008   DEV-AVG=047 NT     SWF=02:006
 XRAY-MAX= M1.4   @ 0609UT    XRAY-MIN= B2.7   @ 2356UT   XRAY-AVG= B6.8
NEUTN-MAX= +001%  @ 1545UT   NEUTN-MIN= -004%  @ 2030UT  NEUTN-AVG= -1.2%
  PCA-MAX= +0.1DB @ 1605UT     PCA-MIN= -0.2DB @ 1455UT    PCA-AVG= +0.0DB
BOUTF-MAX=55502NT @ 0102UT   BOUTF-MIN=55366NT @ 1656UT  BOUTF-AVG=55427NT
GOES7-MAX=E:+117NT@ 0623UT   GOES7-MIN=N:-007NT@ 0101UT  G7-AVG=+071,+060,+012
GOES6-MAX=P:+120NT@ 1839UT   GOES6-MIN=E:-037NT@ 0716UT  G6-AVG=+080,+007,+044
 FLUXFCST=STD:120,120,120;SESC:115,115,110 BAI/PAI-FCST=020,025,020/025,030,020
    KFCST=3344 4333 4455 4444  27DAY-AP=011,010   27DAY-KP=2241 2233 2243 2222
 WARNINGS=*MAJFLR;*SWF;*GSTRM
   ALERTS=**MINFLR:M1.0@0302UTC;**MINFLR:M1.4@0609UTC;**SWEEP:II=2@0022UTC;
          **SWEEP:II=2@0608UTC;**MAJSTRM:ENDED@1500UTC;**TENFLR:140SFU@0609
!!END-DATA!!


SYNOPSIS OF ACTIVITY
--------------------

     Solar activity was moderate today.  Two optically uncorrelated M-class
flares were observed early in the UT day.  The first was an M1.0 event at
03:02 UT.  The second was an M1.4 x-ray event at 06:09 UT and was accompanied
by a moderate Type II sweep at 06:08 UT and a tenflare of 140 sfu.  Another
Type II sweep was observed a few hours earlier and appears to have been tied
to a C1 flare at 01:08 UT.  This latter event may have been associated with a
bright surge on the southwest limb that extended to 0.25 solar radii.

     Region 7276 (N15E26) exhibited minor growth today, but did not change
significantly in structure.  A weak delta configuration appears to exist in
the region.  The spot group is still capable of M-class flares.  There is a
slight chance the group may also support an isolated major M-class flare.

     Other activity of interest included the disappearance of a filament
between 22:35 UT on 10 September and 13:13 UT on 11 September.  The filament
was centered near S25W16 prior to its eruption.

     No new regions were assigned today.

     The ARO 10.7 cm interferometer shows an essentially radio-quiet western
hemisphere.  Region 7276 is associated with the strongest emissions.  Region
7279 (S07E32) also shows moderate 10.7 cm emissions.  These two regions
constitute the major component of the 10.7 cm solar radio flux.  No
significant change in the solar radio flux is expected over the next 72
hours.  Variations will be primarily dependent on changes in these two
regions and possible arrivals of new regions around the east limb.

     Solar activity is expected to continue low to moderate.  Region 7276 is
capable of producing occasional minor M-class flares.  The potential exists
for a major flare from this group.

     The geomagnetic field continued at minor to major storm levels through
the first 9 to 12 hours of the UT day.  Thereafter, conditions stabilized to
mostly unsettled conditions.  By the end of the UT day, the field was quiet
to unsettled.  The major geomagnetic storm ended at 15:00 UT.  The
geomagnetic field is expected to be quiet to occasionally active over the
next 24 hours.  A well placed coronal hole could begin to increase activity
on 13 September.  This should maintain mostly active conditions through 14 or
15 September.

     Levels of auroral activity finally began to subside during the local
evening and early morning hours of 10/11 September.  By 15:00 UT, activity
had diminished to the point where middle latitude observations were no longer
possible.  The warning for middle latitude auroral activity was allowed to
expire at 19:00 UT.  Activity may become mildly enhanced again on 13
September if the disturbance noted above materializes.

     Degraded HF propagation conditions continued over most regions
throughout the day.  Some signal stabilization was observed over the middle
latitude signal paths late in the UT day, although MUFs and general
conditions remain far below normal.  Improvements are expected over the
middle latitudes on 12 September.  High and polar latitudes should also see
some modest improvements on 12 September, although nothing particularly
substantial is expected until after approximately 15 September when levels of
geomagnetic activity begin to subside following the coronal hole disturbance
anticipated on 13 September.  MUFs will remain depressed by between 15 and 35
percent over the next 72 hours.


COPIES OF JOINT USAF/NOAA SESC SOLAR GEOPHYSICAL REPORTS
========================================================

REGIONS WITH SUNSPOTS (LOCATIONS VALID AT 11/2400Z)
---------------------------------------------------
NMBR LOCATION  LO  AREA  Z   LL   NN MAG TYPE
7276  N15E26  262  0210 EKI  12  034 BETA-GAMMA-DELTA
7277  S11W11  299  0000 BXO  03  002 BETA
7278  N11W18  306  0000 AXX  00  001 ALPHA
7279  S07E32  256  0000 AXX  00  001 ALPHA
7280  S14E66  222  0120 CSO  11  002 BETA
REGIONS DUE TO RETURN 12 SEPTEMBER TO 14 SEPTEMBER
NMBR LAT    LO
7268 N05   176


LISTING OF SOLAR ENERGETIC EVENTS FOR 11 SEPTEMBER
--------------------------------------------------
BEGIN  MAX  END  RGN   LOC   XRAY  OP 245MHZ 10CM   SWEEP SWF
 0012 0012 0013                         9100        II
 0024 0024 0025                          640
 0253 0302 0309              M1.0        130
 0603 0609 0616              M1.4       7100 140    II
 1446 1450 1453 7276  N14E28 B9.7  SF    430
 2203 2207 2209              C1.3        780


POSSIBLE CORONAL MASS EJECTION EVENTS FOR 11 SEPTEMBER
------------------------------------------------------
           UT TIME                 OPTICAL          XRAY    RADIO
 BEGIN        MAX      END     LOCATION   TYPE   SIZE  DUR  II IV
10/A2235           B11/1313     S25W16     DSF
11/ 0012               0022     S01W90     RSP   C1.1   72   2
11/B0608              A0610                RSP   M1.4   13   2


INFERRED CORONAL HOLES (LOCATIONS VALID AT 11/2400Z)
----------------------------------------------------
               ISOLATED HOLES AND POLAR EXTENSIONS
      EAST   SOUTH  WEST   NORTH  CAR  TYPE  POL  AREA   OBSN
                 NO DATA AVAILABLE FOR ANALYSIS


**  End of Daily Report  **