code: private double svp( double temp ) {
          double SVP;
  
          SVP = A_SVP * Math.exp((B_SVP * temp) / (C_SVP + temp));
  
          if (temp < 0)
              SVP *= 1.0 + .00972 * temp + .000042 * temp * temp;
  
          return (SVP);
      }
docs: This routine computes the saturated vapor pressure using Handbook of Hydrology eqn 4.2.2 (Pressure in kPa)
  
  @param temp temperature.
  @return saturated vapor pressure.