/******************************************************************************
* @brief Calculate the transpiration from the canopy.
*****************************************************************************/
void
transpiration(layer_data_struct *layer,
veg_var_struct *veg_var,
unsigned short veg_class,
double rad,
double vpd,
double net_short,
double air_temp,
double ra,
double dryFrac,
double delta_t,
double elevation,
double *Wmax,
double *Wcr,
double *Wpwp,
double *layerevap,
double *frost_fract,
double *root,
double shortwave,
double Catm,
double *CanopLayerBnd)
{
extern veg_lib_struct *vic_run_veg_lib;
extern option_struct options;
extern parameters_struct param;
size_t i;
size_t frost_area;
double gsm_inv; /* soil moisture stress factor */
double moist1, moist2; /* tmp holding of moisture */
double evap; /* tmp holding for evap total */
double Wcr1; /* tmp holding of critical water for upper layers */
double root_sum; /* proportion of roots in moist>Wcr zones */
double spare_evap; /* evap for 2nd distribution */
double avail_moist[MAX_LAYERS]; /* moisture available for trans */
double ice[MAX_LAYERS];
double gc;
double *gsLayer = NULL;
size_t cidx;
/**********************************************************************
EVAPOTRANSPIRATION
Calculation of the evapotranspirations
2.18
First part: Soil moistures and root fractions of both layers
influence each other
Re-written to allow for multi-layers.
**********************************************************************/
/**************************************************
Set ice content in all individual layers
**************************************************/
for (i = 0; i < options.Nlayer; i++) {
ice[i] = 0;
for (frost_area = 0; frost_area < options.Nfrost; frost_area++) {
ice[i] += layer[i].ice[frost_area] * frost_fract[frost_area];
}
}
/**************************************************
Compute moisture content in combined upper layers
**************************************************/
moist1 = 0.0;
Wcr1 = 0.0;
for (i = 0; i < options.Nlayer - 1; i++) {
if (root[i] > 0.) {
avail_moist[i] = 0;
for (frost_area = 0; frost_area < options.Nfrost; frost_area++) {
avail_moist[i] +=
((layer[i].moist -
layer[i].ice[frost_area]) * frost_fract[frost_area]);
}
moist1 += avail_moist[i];
Wcr1 += Wcr[i];
}
else {
avail_moist[i] = 0.;
}
}
/*****************************************
Compute moisture content in lowest layer
*****************************************/
i = options.Nlayer - 1;
moist2 = 0;
for (frost_area = 0; frost_area < options.Nfrost; frost_area++) {
moist2 +=
((layer[i].moist -
layer[i].ice[frost_area]) * frost_fract[frost_area]);
}
avail_moist[i] = moist2;
/** Set photosynthesis inhibition factor **/
if (layer[0].moist > vic_run_veg_lib[veg_class].Wnpp_inhib * Wmax[0]) {
veg_var->NPPfactor = vic_run_veg_lib[veg_class].NPPfactor_sat +
(1 - vic_run_veg_lib[veg_class].NPPfactor_sat) *
(Wmax[0] - layer[0].moist) / (Wmax[0] -
vic_run_veg_lib[
veg_class].
Wnpp_inhib *
Wmax[0]);
}
else {
veg_var->NPPfactor = 1.0;
}
/******************************************************************
CASE 1: Moisture in both layers exceeds Wcr, or Moisture in
layer with more than half of the roots exceeds Wcr.
Potential evapotranspiration not hindered by soil dryness. If
layer with less than half the roots is dryer than Wcr, extra
evaporation is taken from the wetter layer. Otherwise layers
contribute to evapotransipration based on root fraction.
******************************************************************/
if (options.SHARE_LAYER_MOIST &&
((moist1 >= Wcr1 && moist2 >= Wcr[options.Nlayer - 1] && Wcr1 > 0.) ||
(moist1 >= Wcr1 && (1 - root[options.Nlayer - 1]) >= 0.5) ||
(moist2 >= Wcr[options.Nlayer - 1] && root[options.Nlayer - 1] >=
0.5))) {
gsm_inv = 1.0;
/* compute whole-canopy stomatal resistance */
if (!options.CARBON || options.RC_MODE == RC_JARVIS) {
/* Jarvis scheme, using resistance factors from Wigmosta et al., 1994 */
veg_var->rc = calc_rc(vic_run_veg_lib[veg_class].rmin, net_short,
vic_run_veg_lib[veg_class].RGL, air_temp, vpd,
veg_var->LAI, gsm_inv, false);
if (options.CARBON) {
for (cidx = 0; cidx < options.Ncanopy; cidx++) {
if (veg_var->LAI > 0) {
veg_var->rsLayer[cidx] = veg_var->rc / veg_var->LAI;
}
else {
veg_var->rsLayer[cidx] = param.HUGE_RESIST;
}
if (veg_var->rsLayer[cidx] > param.CANOPY_RSMAX) {
veg_var->rsLayer[cidx] = param.CANOPY_RSMAX;
}
}
}
}
else {
/* Compute rc based on photosynthetic demand from Knorr 1997 */
calc_rc_ps(vic_run_veg_lib[veg_class].Ctype,
vic_run_veg_lib[veg_class].MaxCarboxRate,
vic_run_veg_lib[veg_class].MaxETransport,
vic_run_veg_lib[veg_class].CO2Specificity,
veg_var->NscaleFactor, air_temp, shortwave,
veg_var->aPARLayer, elevation, Catm,
CanopLayerBnd, veg_var->LAI, gsm_inv, vpd,
veg_var->rsLayer, &(veg_var->rc));
}
/* compute transpiration */
evap = penman(air_temp, elevation, rad, vpd, ra, veg_var->rc,
vic_run_veg_lib[veg_class].rarc) *
delta_t / CONST_CDAY * dryFrac;
/** divide up evap based on root distribution **/
/** Note the indexing of the roots **/
root_sum = 1.0;
spare_evap = 0.0;
for (i = 0; i < options.Nlayer; i++) {
if (avail_moist[i] >= Wcr[i]) {
layerevap[i] = evap * (double) root[i];
}
else {
if (avail_moist[i] >= Wpwp[i]) {
gsm_inv = (avail_moist[i] - Wpwp[i]) /
(Wcr[i] - Wpwp[i]);
}
else {
gsm_inv = 0.0;
}
layerevap[i] = evap * gsm_inv * (double) root[i];
root_sum -= root[i];
spare_evap = evap * (double) root[i] * (1.0 - gsm_inv);
}
}
/** Assign excess evaporation to wetter layer **/
if (spare_evap > 0.0) {
for (i = 0; i < options.Nlayer; i++) {
if (avail_moist[i] >= Wcr[i]) {
layerevap[i] += (double) root[i] * spare_evap / root_sum;
}
}
}
}
/*********************************************************************
CASE 2: Independent evapotranspirations
Evapotranspiration is restricted by low soil moisture. Evaporation
is computed independantly from each soil layer.
*********************************************************************/
else {
/* Initialize conductances for aggregation over soil layers */
gc = 0;
if (options.CARBON) {
gsLayer = calloc(options.Ncanopy, sizeof(*gsLayer));
check_alloc_status(gsLayer, "Memory allocation error.");
for (cidx = 0; cidx < options.Ncanopy; cidx++) {
gsLayer[cidx] = 0;
}
}
for (i = 0; i < options.Nlayer; i++) {
/** Set evaporation restriction factor **/
if (avail_moist[i] >= Wcr[i]) {
gsm_inv = 1.0;
}
else if (avail_moist[i] >= Wpwp[i] && avail_moist[i] < Wcr[i]) {
gsm_inv = (avail_moist[i] - Wpwp[i]) / (Wcr[i] - Wpwp[i]);
}
else {
gsm_inv = 0.0;
}
if (gsm_inv > 0.0) {
/* compute whole-canopy stomatal resistance */
if (!options.CARBON || options.RC_MODE == RC_JARVIS) {
/* Jarvis scheme, using resistance factors from Wigmosta et al., 1994 */
veg_var->rc = calc_rc(vic_run_veg_lib[veg_class].rmin,
net_short,
vic_run_veg_lib[veg_class].RGL,
air_temp, vpd,
veg_var->LAI, gsm_inv, false);
if (options.CARBON) {
for (cidx = 0; cidx < options.Ncanopy; cidx++) {
if (veg_var->LAI > 0) {
veg_var->rsLayer[cidx] = veg_var->rc /
veg_var->LAI;
}
else {
veg_var->rsLayer[cidx] = param.HUGE_RESIST;
}
if (veg_var->rsLayer[cidx] > param.CANOPY_RSMAX) {
veg_var->rsLayer[cidx] = param.CANOPY_RSMAX;
}
}
}
}
else {
/* Compute rc based on photosynthetic demand from Knorr 1997 */
calc_rc_ps(vic_run_veg_lib[veg_class].Ctype,
vic_run_veg_lib[veg_class].MaxCarboxRate,
vic_run_veg_lib[veg_class].MaxETransport,
vic_run_veg_lib[veg_class].CO2Specificity,
veg_var->NscaleFactor, air_temp, shortwave,
veg_var->aPARLayer, elevation, Catm,
CanopLayerBnd, veg_var->LAI, gsm_inv, vpd,
veg_var->rsLayer, &(veg_var->rc));
}
/* compute transpiration */
layerevap[i] = penman(air_temp, elevation, rad, vpd, ra,
veg_var->rc,
vic_run_veg_lib[veg_class].rarc) *
delta_t / CONST_CDAY * dryFrac *
(double) root[i];
if (veg_var->rc > 0) {
gc += 1 / (veg_var->rc);
}
else {
gc += param.HUGE_RESIST;
}
if (options.CARBON) {
for (cidx = 0; cidx < options.Ncanopy; cidx++) {
if (veg_var->rsLayer[cidx] > 0) {
gsLayer[cidx] += 1 / (veg_var->rsLayer[cidx]);
}
else {
gsLayer[cidx] += param.HUGE_RESIST;
}
}
}
}
else {
layerevap[i] = 0.0;
gc += 0;
if (options.CARBON) {
for (cidx = 0; cidx < options.Ncanopy; cidx++) {
gsLayer[cidx] += 0;
}
}
}
} // end loop over layers
/* Now, take the inverse of the conductance */
if (gc > 0) {
veg_var->rc = 1 / gc;
}
else {
veg_var->rc = param.HUGE_RESIST;
}
if (veg_var->rc > param.CANOPY_RSMAX) {
veg_var->rc = param.CANOPY_RSMAX;
}
if (options.CARBON) {
for (cidx = 0; cidx < options.Ncanopy; cidx++) {
if (gsLayer[cidx] > 0) {
veg_var->rsLayer[cidx] = 1 / gsLayer[cidx];
}
else {
veg_var->rsLayer[cidx] = param.HUGE_RESIST;
}
if (veg_var->rsLayer[cidx] > param.CANOPY_RSMAX) {
veg_var->rsLayer[cidx] = param.CANOPY_RSMAX;
}
}
}
if (options.CARBON) {
free((char *) gsLayer);
}
}
/****************************************************************
Check that evapotransipration does not cause soil moisture to
fall below wilting point.
****************************************************************/
for (i = 0; i < options.Nlayer; i++) {
if (ice[i] > 0) {
if (ice[i] >= Wpwp[i]) {
// ice content greater than wilting point can use all unfrozen moist
if (layerevap[i] > avail_moist[i]) {
layerevap[i] = avail_moist[i];
}
}
else {
// ice content less than wilting point restrict loss of unfrozen moist
if (layerevap[i] > layer[i].moist - Wpwp[i]) {
layerevap[i] = layer[i].moist - Wpwp[i];
}
}
}
else {
// No ice restrict loss of unfrozen moist
if (layerevap[i] > layer[i].moist - Wpwp[i]) {
layerevap[i] = layer[i].moist - Wpwp[i];
}
}
if (layerevap[i] < 0.0) {
layerevap[i] = 0.0;
}
}
}
void transpiration(layer_data_struct *layer,
veg_var_struct *veg_var,
int veg_class,
int month,
double rad,
double vpd,
double net_short,
double air_temp,
double ra,
double ppt,
double dryFrac,
double delta_t,
double elevation,
double *depth,
double *Wmax,
double *Wcr,
double *Wpwp,
double *layerevap,
double *frost_fract,
float *root,
double shortwave,
double Catm,
double *CanopLayerBnd)
/**********************************************************************
Computes evapotranspiration for unfrozen soils
Allows for multiple layers.
modifications:
6-8-2000 Modified to use spatially distributed soil frost if
present. KAC
2006-Oct-16 Modified to initialize ice[] for all soil layers
before computing available moisture (to avoid using
uninitialized values later on). TJB
2009-Jun-09 Moved computation of canopy resistance rc out of penman()
and into separate function calc_rc(). TJB
2013-Jul-25 Save dryFrac for use elsewhere. TJB
2013-Jul-25 Added photosynthesis terms. TJB
2014-Apr-25 Switched LAI from veg_lib to veg_var. TJB
**********************************************************************/
{
extern veg_lib_struct *veg_lib;
extern option_struct options;
int i;
int frost_area;
double gsm_inv; /* soil moisture stress factor */
double moist1, moist2; /* tmp holding of moisture */
double evap; /* tmp holding for evap total */
double Wcr1; /* tmp holding of critical water for upper layers */
double root_sum; /* proportion of roots in moist>Wcr zones */
double spare_evap; /* evap for 2nd distribution */
double avail_moist[MAX_LAYERS]; /* moisture available for trans */
double ice[MAX_LAYERS];
double gc;
double *gsLayer;
int cidx;
int flag_irr;
/**********************************************************************
EVAPOTRANSPIRATION
Calculation of the evapotranspirations
2.18
First part: Soil moistures and root fractions of both layers
influence each other
Re-written to allow for multi-layers.
**********************************************************************/
flag_irr = veg_lib[veg_class].irr_active[month-1];
/**************************************************
Set ice content in all individual layers
**************************************************/
for(i=0;i<options.Nlayer;i++){
ice[i] = 0;
for ( frost_area = 0; frost_area < options.Nfrost; frost_area++ ) {
ice[i] += layer[i].ice[frost_area] * frost_fract[frost_area];
}
}
/**************************************************
Compute moisture content in combined upper layers
**************************************************/
moist1 = 0.0;
Wcr1 = 0.0;
for(i=0;i<options.Nlayer-1;i++){
if(root[i] > 0.) {
avail_moist[i] = 0;
for ( frost_area = 0; frost_area < options.Nfrost; frost_area++ ) {
avail_moist[i] += ((layer[i].moist - layer[i].ice[frost_area]) * frost_fract[frost_area]);
}
moist1+=avail_moist[i];
Wcr1 += Wcr[i];
}
else avail_moist[i]=0.;
}
/*****************************************
Compute moisture content in lowest layer
*****************************************/
i = options.Nlayer - 1;
moist2 = 0;
for ( frost_area = 0; frost_area < options.Nfrost; frost_area++ )
moist2 += ((layer[i].moist - layer[i].ice[frost_area]) * frost_fract[frost_area]);
avail_moist[i]=moist2;
/** Set photosynthesis inhibition factor **/
if (layer[0].moist > veg_lib[veg_class].Wnpp_inhib*Wmax[0])
veg_var->NPPfactor = veg_lib[veg_class].NPPfactor_sat + (1 - veg_lib[veg_class].NPPfactor_sat) * (Wmax[0] - layer[0].moist) / (Wmax[0] - veg_lib[veg_class].Wnpp_inhib*Wmax[0]);
else
veg_var->NPPfactor = 1.0;
/******************************************************************
CASE 1: Moisture in both layers exceeds Wcr, or Moisture in
layer with more than half of the roots exceeds Wcr.
Potential evapotranspiration not hindered by soil dryness. If
layer with less than half the roots is dryer than Wcr, extra
evaporation is taken from the wetter layer. Otherwise layers
contribute to evapotransipration based on root fraction.
******************************************************************/
if( options.SHARE_LAYER_MOIST &&
( (moist1>=Wcr1 && moist2>=Wcr[options.Nlayer-1] && Wcr1>0.) ||
(moist1>=Wcr1 && (1-root[options.Nlayer-1])>= 0.5) ||
(moist2>=Wcr[options.Nlayer-1] && root[options.Nlayer-1]>=0.5) ) ) {
gsm_inv=1.0;
/* compute whole-canopy stomatal resistance */
if (!options.CARBON || options.RC_MODE == RC_JARVIS) {
/* Jarvis scheme, using resistance factors from Wigmosta et al., 1994 */
veg_var->rc = calc_rc(veg_lib[veg_class].rmin, net_short,
veg_lib[veg_class].RGL, air_temp, vpd,
veg_var->LAI, gsm_inv, FALSE,flag_irr);
if (options.CARBON) {
for (cidx=0; cidx<options.Ncanopy; cidx++) {
if (veg_var->LAI > 0)
veg_var->rsLayer[cidx] = veg_var->rc / veg_var->LAI;
else
veg_var->rsLayer[cidx] = HUGE_RESIST;
if (veg_var->rsLayer[cidx] > RSMAX) veg_var->rsLayer[cidx] = RSMAX;
}
}
}
else {
/* Compute rc based on photosynthetic demand from Knorr 1997 */
calc_rc_ps(veg_lib[veg_class].Ctype, veg_lib[veg_class].MaxCarboxRate,
veg_lib[veg_class].MaxETransport, veg_lib[veg_class].CO2Specificity,
veg_var->NscaleFactor, air_temp, shortwave, veg_var->aPARLayer, elevation, Catm,
CanopLayerBnd, veg_var->LAI, gsm_inv, vpd, veg_var->rsLayer, &(veg_var->rc));
}
/* compute transpiration */
evap = penman(air_temp, elevation, rad, vpd, ra, veg_var->rc,
veg_lib[veg_class].rarc) * delta_t / SEC_PER_DAY * dryFrac;
/** divide up evap based on root distribution **/
/** Note the indexing of the roots **/
root_sum=1.0;
spare_evap=0.0;
for(i=0;i<options.Nlayer;i++){
if(avail_moist[i]>=Wcr[i]){
layerevap[i]=evap*(double)root[i];
}
else {
if (avail_moist[i] >= Wpwp[i])
gsm_inv = (avail_moist[i] - Wpwp[i]) /
(Wcr[i] - Wpwp[i]);
else
gsm_inv=0.0;
layerevap[i] = evap*gsm_inv*(double)root[i];
root_sum -= root[i];
spare_evap = evap*(double)root[i]*(1.0-gsm_inv);
}
}
/** Assign excess evaporation to wetter layer **/
if(spare_evap>0.0){
for(i=0;i<options.Nlayer;i++){
if(avail_moist[i] >= Wcr[i]){
layerevap[i] += (double)root[i]*spare_evap/root_sum;
}
}
}
}
/*********************************************************************
CASE 2: Independent evapotranspirations
Evapotranspiration is restricted by low soil moisture. Evaporation
is computed independantly from each soil layer.
*********************************************************************/
else {
/* Initialize conductances for aggregation over soil layers */
gc = 0;
if (options.CARBON) {
gsLayer = (double *)calloc(options.Ncanopy, sizeof(double));
for (cidx=0; cidx<options.Ncanopy; cidx++) {
gsLayer[cidx] = 0;
}
}
for (i=0;i<options.Nlayer;i++) {
/** Set evaporation restriction factor **/
if(avail_moist[i] >= Wcr[i])
gsm_inv = 1.0;
else if(avail_moist[i] >= Wpwp[i] && avail_moist[i] < Wcr[i])
gsm_inv = (avail_moist[i] - Wpwp[i]) / (Wcr[i] - Wpwp[i]);
else
gsm_inv = 0.0;
if(gsm_inv > 0.0){
/* compute whole-canopy stomatal resistance */
if (!options.CARBON || options.RC_MODE == RC_JARVIS) {
/* Jarvis scheme, using resistance factors from Wigmosta et al., 1994 */
veg_var->rc = calc_rc(veg_lib[veg_class].rmin, net_short,
veg_lib[veg_class].RGL, air_temp, vpd,
veg_var->LAI, gsm_inv, FALSE,flag_irr);
if (options.CARBON) {
for (cidx=0; cidx<options.Ncanopy; cidx++) {
if (veg_var->LAI > 0)
veg_var->rsLayer[cidx] = veg_var->rc / veg_var->LAI;
else
veg_var->rsLayer[cidx] = HUGE_RESIST;
if (veg_var->rsLayer[cidx] > RSMAX) veg_var->rsLayer[cidx] = RSMAX;
}
}
}
else {
/* Compute rc based on photosynthetic demand from Knorr 1997 */
calc_rc_ps(veg_lib[veg_class].Ctype, veg_lib[veg_class].MaxCarboxRate,
veg_lib[veg_class].MaxETransport, veg_lib[veg_class].CO2Specificity,
veg_var->NscaleFactor, air_temp, shortwave, veg_var->aPARLayer, elevation, Catm,
CanopLayerBnd, veg_var->LAI, gsm_inv, vpd, veg_var->rsLayer, &(veg_var->rc));
}
/* compute transpiration */
layerevap[i] = penman(air_temp, elevation, rad, vpd, ra, veg_var->rc,
veg_lib[veg_class].rarc) * delta_t / SEC_PER_DAY * dryFrac * (double)root[i];
if (veg_var->rc > 0)
gc += 1/(veg_var->rc);
else
gc += HUGE_RESIST;
if (options.CARBON) {
for (cidx=0; cidx<options.Ncanopy; cidx++) {
if (veg_var->rsLayer[cidx] > 0)
gsLayer[cidx] += 1/(veg_var->rsLayer[cidx]);
else
gsLayer[cidx] += HUGE_RESIST;
}
}
}
else {
layerevap[i] = 0.0;
gc += 0;
if (options.CARBON) {
for (cidx=0; cidx<options.Ncanopy; cidx++) {
gsLayer[cidx] += 0;
}
}
}
} // end loop over layers
/* Now, take the inverse of the conductance */
if (gc > 0)
veg_var->rc = 1/gc;
else
veg_var->rc = HUGE_RESIST;
if (veg_var->rc > RSMAX) veg_var->rc = RSMAX;
if (options.CARBON) {
for (cidx=0; cidx<options.Ncanopy; cidx++) {
if (gsLayer[cidx] > 0)
veg_var->rsLayer[cidx] = 1/gsLayer[cidx];
else
veg_var->rsLayer[cidx] = HUGE_RESIST;
if (veg_var->rsLayer[cidx] > RSMAX) veg_var->rsLayer[cidx] = RSMAX;
}
}
if (options.CARBON) free((char *)gsLayer);
}
/****************************************************************
Check that evapotransipration does not cause soil moisture to
fall below wilting point.
****************************************************************/
for ( i = 0; i < options.Nlayer; i++ ) {
if ( ice[i] > 0 ) {
if ( ice[i] >= Wpwp[i] ) {
// ice content greater than wilting point can use all unfrozen moist
if ( layerevap[i] > avail_moist[i] ) layerevap[i] = avail_moist[i];
}
else {
// ice content less than wilting point restrict loss of unfrozen moist
if ( layerevap[i] > layer[i].moist - Wpwp[i] )
layerevap[i] = layer[i].moist - Wpwp[i];
}
}
else {
// No ice restrict loss of unfrozen moist
if ( layerevap[i] > layer[i].moist - Wpwp[i] )
layerevap[i] = layer[i].moist - Wpwp[i];
}
if ( layerevap[i] < 0.0 ) layerevap[i] = 0.0;
}
}
