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Fortran

SUBROUTINE DIEOFFS(TOFDAY,DAYOFY,DELT,T90)
C Calculates faecal coliform dieoff T90 based on solar radiation during
C the time interval DELT(sec).
C Input Time of day (hrs) TOFDAY, Day of year (1-366) DAYOFY.
C Output T90 (hrs)
REAL TOFDAY,DAYOFY,LAT,LONG,ELEVAT,DELT,DELTH,STANM
REAL TSOLHR,T90
COMMON/INPUTS/LAT,LONG,ELEVAT,STANM
COMMON/MET/WETBLB,ATMPR,DRYBLB,CLOUD,DAT
LAT=-33.8
LONG=151.3
ELEVAT=0.0 ! Elevation (m)
DELTH=DELT/3600.
STANM=150.0 ! Longitude corresponding to standard time
WETBLB=20.0 ! Dry bulb temp
DRYBLB=17.5 ! Wet bulb temp (depends on humidity)
CLOUD=0.0 ! Cloud cover (0-1)
ATMPR=1015. ! Atm pressure
DAT=0.07 ! Dust attenuation
C Dieoff-Solar Radiation Parameters
C Ref. Caldwell-Connell Engineers (1980) Fig. 7.6
A=3.3
B=-0.7
CALL HEATEX(TOFDAY,DAYOFY,DELT,TSOLHR)
C Convert radiation in DELT to hourly solar radiation in MJ/m2
TSOLHR=TSOLHR/1000./DELTH
C PRINT*,TSOLHR
C Calculate the T90
IF (TSOLHR.LT.0.08) THEN
T90=20.
ELSE
T90=A*(TSOLHR**(B))
ENDIF
RETURN
END