estimate_t1.c

超强的大尺度水文模拟工具

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <vicNl.h>

static char vcid[] = "$Id: estimate_T1.c,v 4.2 2000/05/16 21:57:54 vicadmin Exp $";

double estimate_T1(double Ts, 
		   double T1_old,
		   double T2,
		   double D1, 
		   double D2, 
		   double kappa1, 
		   double kappa2, 
		   double Cs1, 
		   double Cs2, 
		   double dp,
		   double delta_t) {
/**********************************************************************
  estimate_T1                Keith Cherkauer          July 15, 1998

  uses Xu Liangs 3-layer energy balance formulation to estimate the 
  temperature between the first and second layers.  Formerly calculated
  independently in each of the surface energy balance equation routines.

  Modifications:
  01-20-00 removed from end of func_surf_energy_bal.c and put into a
           separate file                                           KAC

**********************************************************************/

  double C1;
  double C2;
  double C3;
  double T1;

  C1 = Cs2 * dp / D2 * ( 1. - exp(-D2/dp));
  C2 = - ( 1. - exp(D1/dp) ) * exp(-D2/dp);
  C3 = kappa1/D1 - kappa2/D1 + kappa2/D1*exp(-D1/dp);

  T1 = (kappa1/2./D1/D2*(Ts) + C1/delta_t*T1_old
     + (2.*C2-1.+exp(-D1/dp))*kappa2/2./D1/D2*T2)
     / (C1/delta_t + kappa2/D1/D2*C2 + C3/2./D2);

  return(T1);

}