Particle Cross Section Regression Line
Posted: July 11th, 2013, 11:15 am
How is the location of the red regression line shown in the particle cross section plot determined?
The computation of the regression line through the particle positions is determined using the following fortran routine....
DO N=1,NUMTIM
! time period index record
READ(32)NUMPAR,NUMPOL,IYR,IMO,IDA,IHR
CNTR=0.0
SUMX=0.0
SUMY=0.0
SUMXY=0.0
SUMX2=0.0
SUMY2=0.0
DO J=1,NUMPAR
READ(32)(MASS(I),I=1,NUMPOL)
READ(32)TLAT,TLON,ZLVL,SIGH,SIGV,SIGX
READ(32)PAGE,HDWP,PTYP,PGRD,NSORT
IF(SUM(MASS).GT.0.0)THEN
CALL CLL2XY(PARMAP,TLAT,TLON,X1,Y1)
! regression sums
CNTR=CNTR+1.0
SUMX=SUMX+X1
SUMY=SUMY+Y1
SUMXY=SUMXY+X1*Y1
SUMX2=SUMX2+X1*X1
SUMY2=SUMY2+Y1*Y1
END IF
END DO
! regression line to determine cross-section
IF(CNTR.GE.2.0)THEN
SLOPE(N)=(CNTR*SUMXY-SUMX*SUMY)/(CNTR*SUMX2-SUMX*SUMX)
YNODE(N)=SUMY/CNTR-SLOPE(N)*SUMX/CNTR
ELSE
SLOPE(N)=1.0
YNODE(N)=0.0
END IF
END DO