164
Carlos A. Gracia, Estfbaliz Tello, Santiago Sabate and Juan Bellot
12.1.1 Input Data
The input data of GOTILWA comprise three different sets (Table 12.1). A first
data set is the climate data: daily values of maximum and minimum temperature cae), rainfall (mm day-I), duration of rain (min day-I), solar irradiance (MJ day-I) and potential evapotranspiration (Eo, mm day-I). Daily Eo is
used to calculate the evaporative coefficient (Specht 1972) and the actual
evapotranspiration (E.). If Eo is not available, GOTILWA estimates the daily
values using the method of Samani and Heargreaves (1985), based on the use
of maximum and minimum temperature and solar irradiance above the atmosphere, as described by McKenney and Rosenberg (1993).
Table 12.1. Input variables used by GOTILWA to simulate forest growth
Climatic variables
Maximum daily temperature
Minimum daily temperature
Precipitation
Irradiance
Duration of rainfall
Potential evapotranspiration
Catchment or stand variables
Altitude at highest point
Altitude of discharge point
Horizontal distance between these points
Length of discharge front
Soil depth at highest point
Soil depth at discharge point
Maximum soil water storage capacity
Minimum soil water storage capacity
Soil hydraulic conductivity
Tree variables and functions
Throughfall function
Interception function
Stemflow function
Aboveground biomass function
Ratio belowgroundlaboveground biomass
Fraction cross-sectional area of sapwood
Leaf area per unit of sapwood
Leaf specific mass
Fine root biomass/leaf biomass
Water use efficiency at maximum PAR
Water use efficiency at minimum PAR
Mobile carbon stored in leaves
Mobile carbon stored in woody tissues
Fraction of incident PAR reaching the soil
Fraction of respiring sapwood
°C
°C
mmday-l
MJ day-l
min day-l
mmday-l
ma.s.!.
ma.s.!.
m
m
m
m
m
m
m day-l
T= a R + b Dr+c
I = a LA R e cR
S = [ 1 - e a LA 1 [b (R ,- I)c 1
B = a Db
Unitless
Unitless
m 2 cm- 2
mgcm- 2
Unitless
mmol CO2 mol- l H20
mmol CO2 mor l H20
gl100 g
gl100 g
%
Value per one
T, throughfall; I, interception; S, stemflow; R, rainfall; D" duration of rainfall; LA, leaf area; D,
tree dbh.
Carlos A. Gracia, Estfbaliz Tello, Santiago Sabate and Juan Bellot
12.1.1 Input Data
The input data of GOTILWA comprise three different sets (Table 12.1). A first
data set is the climate data: daily values of maximum and minimum temperature cae), rainfall (mm day-I), duration of rain (min day-I), solar irradiance (MJ day-I) and potential evapotranspiration (Eo, mm day-I). Daily Eo is
used to calculate the evaporative coefficient (Specht 1972) and the actual
evapotranspiration (E.). If Eo is not available, GOTILWA estimates the daily
values using the method of Samani and Heargreaves (1985), based on the use
of maximum and minimum temperature and solar irradiance above the atmosphere, as described by McKenney and Rosenberg (1993).
Table 12.1. Input variables used by GOTILWA to simulate forest growth
Climatic variables
Maximum daily temperature
Minimum daily temperature
Precipitation
Irradiance
Duration of rainfall
Potential evapotranspiration
Catchment or stand variables
Altitude at highest point
Altitude of discharge point
Horizontal distance between these points
Length of discharge front
Soil depth at highest point
Soil depth at discharge point
Maximum soil water storage capacity
Minimum soil water storage capacity
Soil hydraulic conductivity
Tree variables and functions
Throughfall function
Interception function
Stemflow function
Aboveground biomass function
Ratio belowgroundlaboveground biomass
Fraction cross-sectional area of sapwood
Leaf area per unit of sapwood
Leaf specific mass
Fine root biomass/leaf biomass
Water use efficiency at maximum PAR
Water use efficiency at minimum PAR
Mobile carbon stored in leaves
Mobile carbon stored in woody tissues
Fraction of incident PAR reaching the soil
Fraction of respiring sapwood
°C
°C
mmday-l
MJ day-l
min day-l
mmday-l
ma.s.!.
ma.s.!.
m
m
m
m
m
m
m day-l
T= a R + b Dr+c
I = a LA R e cR
S = [ 1 - e a LA 1 [b (R ,- I)c 1
B = a Db
Unitless
Unitless
m 2 cm- 2
mgcm- 2
Unitless
mmol CO2 mol- l H20
mmol CO2 mor l H20
gl100 g
gl100 g
%
Value per one
T, throughfall; I, interception; S, stemflow; R, rainfall; D" duration of rainfall; LA, leaf area; D,
tree dbh.