Model Change Bulletin              
              
                                   MCB#2                         7/18/91

                           CTSCREEN (dated 91107)


     This Model Change Bulletin documents the changes made to the CTSCREEN 
model and its associated programs since their original installation as
CTSCREEN (dated 91051) on the SCRAM bulletin board.  In the earlier
model version, the effective stack height was not being reset to its initial
value.  This occurred after finishing calculations for receptors utilizing
transitional plume rise.  These changes correct that problem.  Concentration
results should vary from previous model version results depending upon the
height of the receptor with respect to the plume height.  Also, several
improvements have been made to the menu driven program used in running the
model.  

Model Changes Implemented:
=========================

CTSCREEN: 

1.   In the main program, CTSCREEN, two of the header lines were changed to
reflect the new CTSCREEN julian date and model change bulletin number.  The
following two lines were changed from:

C                          CTSCREEN (DATED 91051)                           *
C             *** SEE CTSCREEN MODEL CHANGE BULLETIN MCB#1 ***              *

to:

C                          CTSCREEN (DATED 91107)                           *
C             *** SEE CTSCREEN MODEL CHANGE BULLETIN MCB#2 ***              *


2.  In the DAYSCR.FOR subroutine, the following changes were made to 
correctly model situations in which transitional plume rise is used.

        a) The coding was changed from:

C  RISE, XFIN ARE RETURNED

to:

C  ADDED FLAG ITRANPR - A 1 MEANS THAT TRANPR WAS CALLED.  THIS IS 
C  NECESSARY BECAUSE IF WE RESET THE EFFECTIVE STACK HEIGHT ARRAY,
C  WE NEED TO RESET IT AFTER OUR CALCULATIONS FOR THIS RECEPTOR ARE
C  COMPLETED -DJB 4/16/91

C  RISE, XFIN ARE RETURNED


        b) The coding was changed from:

       IF (XP .GE. XF .OR. FB .EQ. 0.0) THEN
         TRISE = -999.0

to:

       IF (XP .GE. XF .OR. FB .EQ. 0.0) THEN
         ITRANPR = 0
         TRISE = -999.0


        c) The coding was changed from:

       ELSE 
         CALL TRANPR(XP,TRISE)

to:

       ELSE 
         ITRANPR = 1
         CALL TRANPR(XP,TRISE)


        d) The coding was changed from:

         IF (RISE .NE. TRISE) XF = XP
         HPL = HS + RISE
         EFFSH(1) = HPL
         EFFSH(2) = HPL
         EFFSH(3) = 2.0*XMH - HPL
         EFFSH(4) = 2.0*XMH - HPL
         EFFSH(5) = 2.0*XMH + HPL
         EFFSH(6) = 2.0*XMH + HPL
       ENDIF            

to:

         IF (RISE .NE. TRISE) XF = XP
         HPLTR = HS + RISE
         EFFSH(1) = HPLTR
         EFFSH(2) = HPLTR
         EFFSH(3) = 2.0*XMH - HPLTR
         EFFSH(4) = 2.0*XMH - HPLTR
         EFFSH(5) = 2.0*XMH + HPLTR
         EFFSH(6) = 2.0*XMH + HPLTR
       ENDIF            


        e) The coding was changed from:

260    CONTINUE

to:

C IF WE CALLED TRANPR (ITRANPR = 1) THE RESET THE EFFSH ARRAY USING
C FINAL PLUME HEIGHT (HPL) FOR NXT RECEPTOR 
        IF (ITRANPR .GT. 0) THEN
          EFFSH(1) = HPL
          EFFSH(2) = HPL
          EFFSH(3) = 2.0*XMH - HPL
          EFFSH(4) = 2.0*XMH - HPL
          EFFSH(5) = 2.0*XMH + HPL
          EFFSH(6) = 2.0*XMH + HPL
        ENDIF

260    CONTINUE


3.  In the PAGE.FOR subroutine the CTSCREEN julian date was updated to reflect 
the model update. The coding was changed from: 

6010   FORMAT('1','CTSCREEN Dated(91051)',T72,'PAGE',1X,I3/)

to:

6010   FORMAT('1','CTSCREEN Dated(91107)',T72,'PAGE',1X,I3/)



4.  In the NITCALC subroutine the message indicating an endless loop in path 
was corrected.  

        a)  The code was changed from:

365         CONTINUE
        IF (IFLOW .EQ. 1) WRITE(IOUT,9365) JYR, JMO, JDY, KJCD, JHR
        IF (IFLOW .EQ. 2) THEN
          WRITE(IOUT,9366) NS,NHL,JYR,JMO,JDY,KJCD,JHR
          WRITE(0,9366) NS,NHL,JYR,JMO,JDY,KJCD,JHR
        ENDIF

to:

365         CONTINUE
        IF (IFLOW .EQ. 1) THEN
          IF (ISCRN .EQ. 0) THEN
            WRITE(IOUT,9365) KYR, KMO, KDY, KJCD, KHR
          ELSE
            WRITE(IOUT,9364) ISIM
          ENDIF
        ENDIF
        IF (IFLOW .EQ. 2) THEN
          IF (ISCRN .EQ. 0) THEN
            WRITE(IOUT,9366) NS,NHL,KYR,KMO,KDY,KJCD,KHR
            WRITE(0,9366) NS,NHL,KYR,KMO,KDY,KJCD,KHR
          ELSE
            WRITE(IOUT,9367)NS,NHL,ISIM
            WRITE(0,9367)NS,NHL,ISIM
          ENDIF
        ENDIF


        b) The code was changed from:

8020    FORMAT(1X,I3,' WRAP N/A (PLUME MISSES HILL)')
9365    FORMAT(/' FLOW FIELD ALGORITHM SUBJECTED TO INPUT DATA BEYOND ',

to:

8020    FORMAT(1X,I3,' WRAP N/A (PLUME MISSES HILL)')
9364    FORMAT(/' FLOW FIELD ALGORITHM SUBJECTED TO INPUT DATA BEYOND ',
     *  'ITS DESIGN CRITERIA;',/,' NO PREDICTIONS: SIMULATION = ',I10/)
9365    FORMAT(/' FLOW FIELD ALGORITHM SUBJECTED TO INPUT DATA BEYOND ',


        c) The code was changed from:

     *  I2,'  MONTH = ',I2,'  DAY = ',I2,'  JCD = ',I3,'  HOUR = ',I2/)
9375    FORMAT(/' WIND SPEED LT 1 M/S, NO PREDICTIONS THIS HOUR',

to:

     *  I2,'  MONTH = ',I2,'  DAY = ',I2,'  JCD = ',I3,'  HOUR = ',I2/)
9367    FORMAT(/' ENDLESS LOOP IN PATH; STACK ',I2,' HILL ',I2,
     *  /' NO PREDICTIONS: SIMULATION = ',I10/)
9375    FORMAT(/' WIND SPEED LT 1 M/S, NO PREDICTIONS THIS HOUR',



5.  In the CONCALC.FOR subroutine the code was changed from:

       ENDIF     

to:

C    IF CONC(1) = -999 THERE WAS A PROBLEM, GO ON TO NEXT WIND DIRECTION
          IF (CONC(1) .LT. 0) GOTO 999

       ENDIF