/disk01/web/ocssw/build/src/libseawifs/out_band_corr.c (r8202/r3)

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/*

 $Header$
 $Log$



From yeh@calval  Tue Mar 19 16:04:26 1996
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From: yeh@calval (Eueng-nan Yeh)
Message-Id: <199603192104.QAA03350@calval.gsfc.nasa.gov>
Subject: out-of-band subroutine
To: frank
Date: Tue, 19 Mar 1996 16:04:18 -0500 (EST)
Reply-To: yeh@calval (Eueng-nan Yeh)
Organization: NASA/Goddard/Laboratory for Hydrospheric Processes/SeaWiFS
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Status: RO

*/


#include <stdio.h>
#define NBAND 8
#define NSAMPLE 1285


#ifdef __STDC__
int out_band_corr(float r[8][1285],float oxygen,int xsample)
#else
int out_band_corr(r,oxygen,xsample)
/************************************************************2*******
/To perform out-of-band correction
/-------------------------------------------------------------
/Inputs:
/  r  float[8][1285]  level-1 radiances (band 1 to 8) per line.
/  oxygen  float      Oxygen correction factor; =1 if r(765nm) already 
/                     corrected; =1.12 if not.
/  xsample int        Number of data points per line (max 1285).
/Outputs:
/  r  float[8][1285]  Out-of-band corrected radiances per line.
/  Return value=-1 for open data file failure; otherwise O.K.
/-------------------------------------------------------------
/
/  Created by Eueng-nan Yeh      GSC/SAIC          10/10/95
/
/%***********************************************************2******/
float r[NBAND][NSAMPLE];
float oxygen;
int   xsample;
#endif /* __STDC__ */
{
  int   i,m,id=1;

  float wl[9]={412.,443.,490.,510.,555.,670.,765.,865.,965.};
/*Spectral response of band 8 divided into six components. */
  float s[6]={0.583,0.829,6.251,13.533,1013.592,9.374};
  float s5[3]={5.261,488.215,7.475};
  float s6[3]={2.592,491.802,2.112}; 
/*Out of band ratio==within-band response/total response*/
  float br[8]={0.9943,0.9949,0.9930,0.9934,0.9734,0.9856,0.9844,0.9417};
  float x,ra,r5,r6,r8,r9,br5,br6,br8;
  if(id==1){      /*simple method */
    ra=(wl[8]-wl[7])/(wl[7]-wl[6]);
    for(m=0; m<xsample; m++) {                  /*process one line*/
      r5=r[4][m];
      r6=r[5][m];
      r8=r[7][m];
      for(i=0; i<8; i++) r[i][m] *= br[i];      /*adjust 0-7 first */
      r9=r[7][m]+ra*(r[7][m]-oxygen*r[6][m]);   /*r[6] for wl=765nm */ 
      x=r[7][m]*s[4];
      br8=x/(r[0][m]*s[0]+r[3][m]*s[1]+r[4][m]*s[2]
            +oxygen*r[6][m]*s[3]+x+r9*s[5]);
      r[7][m] = r8* br8;
      x=r[5][m]*s6[1];         /* band 6*/
      br6=x/(r[2][m]*s6[0]+x+r[7][m]*s6[2]);
      r[5][m] = r6*br6;
      x=r[4][m]*s5[1];         /* band 5*/
      br5=x/(r[1][m]*s5[0]+x+r[5][m]*s5[2]);
      r[4][m] = r5*br5;
    }
  }
  return(0);
}

#ifdef TEST_OOB
void main()
{
  int i,j;
/* Typical SeaWiFS radiances TM 1 Table 1 or TM 22 Table 26.  */
  float rad[NBAND][NSAMPLE]={{9.10, 9.10,9.10},{8.41,8.41,8.41}
   ,{6.56,6.56,6.56},{5.64,5.64,5.64}
   ,{4.57,4.57,4.57},{2.46,2.46,2.46}
   ,{1.61,1.61,1.61},{1.0,1.0,1.09}};
  float r[NBAND][NSAMPLE],oxygen=1.12; /*oxygen absorption correc. factor*/
  float ra[NBAND];

  for(i=0; i<8; i++) printf("%7.5f  ",rad[i][2]);
  printf("\n");
  for(i=0;i<8;i++) for(j=0;j<3;j++) r[i][j]=rad[i][j];
  out_band_corr(r,oxygen,3);
  for(i=0; i<8; i++) printf("%7.5f  ",r[i][2]);
  printf("\n");
  for(i=0; i<8; i++) ra[i]=r[i][2]/rad[i][2];
  for(i=0; i<8; i++) printf("%7.5f  ",ra[i]);
  printf("\n\n");

  exit(0);
}
#endif /* TEST_OOB */

/* Test Result

From yeh@calval  Tue Mar 19 16:09:54 1996
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From: yeh@calval (Eueng-nan Yeh)
Message-Id: <199603192109.QAA04098@calval.gsfc.nasa.gov>
Subject: out-of-band result
To: frank
Date: Tue, 19 Mar 1996 16:09:47 -0500 (EST)
Reply-To: yeh@calval (Eueng-nan Yeh)
Organization: NASA/Goddard/Laboratory for Hydrospheric Processes/SeaWiFS
X-Mailer: ELM [version 2.4 PL0]
MIME-Version: 1.0
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Content-Length: 220       
Status: RO

9.10000  8.41000  6.56000  5.64000  4.57000  2.46000  1.61000  1.09000  
9.04813  8.36711  6.51408  5.60278  4.44292  2.42131  1.58488  1.02651  
0.99430  0.99490  0.99300  0.99340  0.97219  0.98427  0.98440  0.94175  

*/