:Product: 19980826SGAS.txt
:Issued: 1998 Aug 26 0245 UTC
# Prepared jointly by the U.S. Dept. of Commerce, NOAA,
# Space Environment Center and the U.S. Air Force.
#
JOINT USAF/NOAA SOLAR AND GEOPHYSICAL ACTIVITY SUMMARY
SGAS NUMBER 238 ISSUED AT 0245Z ON 26 AUG 1998
THIS REPORT IS COMPILED FROM DATA RECEIVED AT SWO ON 25 AUG
A.  ENERGETIC EVENTS
BEGIN  MAX  END  RGN   LOC   XRAY  OP 245MHZ 10CM   SWEEP
0000 0000 0135                                        IV
B.  PROTON EVENTS:  GREATER THAN 10 MEV AND GREATER THAN 100 MEV
ALERTS CONTINUE TO BE IN EFFECT FROM THE X1/3B FLARE YESTERDAY.  GT
10 MEV FLUX HAS REACHED VALUES OF 209 PFU AT 25/2300UT, AND APPEARS
TO REMAIN AT A CONSTANT LEVEL.  GT 100 MEV FLUX HAS DECLINED FROM
ITS PEAK OF 3.6 PFU AT 25/0055UT, BUT HAS REMAINED STEADY AT 0.7 PFU
OVER THE LAST 12 HOURS.  WHEN THE SHOCK FROM THE FLARE REACHES
EARTH, PROTON DENSITIES ARE EXPECTED TO CLIMB BY 1 TO 2 ORDERS OF
MAGNITUDE.  THE SHOCK IS EXPECTED BETWEEN 26/1200-2400UT.
C.  GEOMAGNETIC ACTIVITY SUMMARY:  THE SOLAR ACTIVITY OCCURRING LATE
ON AUGUST 24 PRODUCED A SMALL PROTON EVENT THAT EXTENDED UP TO
INCLUDE VERY ENERGETIC PARTICLES.  GREATER THAN 10 MEV PROTONS BEGAN
RISING AT 24/2230 UT AND CROSSED THE SEC EVENT THRESHOLD AT 24/2355
UT.  FLUXES REACHED A MAXIMUM OF 190 PFU AT 25/0435 UT THEN DECLINED
TO ABOUT 100 PFU AND REMAIN STEADY AT THAT LEVEL.  GREATER THAN 100
MEV PROTONS BEGAN RISING AT 24/2230 AND REACHED EVENT THRESHOLD AT
24/2245 UT.  THESE PEAKED AT ABOUT 3.5 PFU AT 23/0055 UT BUT
CURRENTLY REMAIN ELEVATED AT ABOUT ONE PFU.  NEUTRON MONITOR DATA
AND THE GOES ENERGETIC PARTICLE SENSOR MEASURING PROTONS ABOVE 850
MEV SHOWED A SMALL RISE BEGINNING ABOUT 24/2210 UT.  THE THULE
RIOMETER HAS REGISTERED BETWEEN ONE AND TWO DB ABSORPTION SINCE THE
PARTICLE EVENT BEGAN. THE GEOMAGNETIC FIELD HAS BEEN QUIET TO
UNSETTLED.  SMALL PERTURBATIONS PASS THE ACE SATELLITE AT RANDOM
INTERVALS OF ABOUT ONE TO TWO HOURS.  MID-LATITUDE K-INDICES HAVE
RANGED FROM 1 TO FOUR OVER THE PAST 24 HOURS.
D.  STRATWARM:  NONE.
E.  DAILY INDICES: (REAL-TIME PRELIMINARY/ESTIMATED VALUES)
10 CM 122  SSN 109  AFR/AP 009/011   X-RAY BACKGROUND C4.9
DAILY PROTON FLUENCE (FLUX ACCUMULATION OVER 24 HRS)
GT 1 MEV 6.0E+07   GT 10 MEV 1.0E+07 P/(CM2-STER-DAY)
(GOES-8 SATELLITE SYNCHRONOUS ORBIT W75 DEGREES)
DAILY ELECTRON FLUENCE
GT 2 MEV 3.40E+07 E/(CM2-STER-DAY)
(GOES-8 SATELLITE SYNCHRONOUS ORBIT W75 DEGREES)
3 HOUR K-INDICES:
BOULDER 2 4 1 1 2 1 3 2 PLANETARY 3 3 1 2 2 3 3 3
F.  COMMENTS:  NONE.