medfate (version 0.2.2)

swbprocesses: Soil infiltration and bare soil evaporation

Description

Function swb.SoilInfiltration calculates the amount of net precipitation that infiltrates into the topsoil, according to the USDA SCS curve number method (Boughton 1989). The remaining is assumed to be lost as surface runoff. Function swb.SoilEvaporation calculates the amount of evaporation from bare soil, following Ritchie (1972).

Usage

swb.SoilInfiltration(NetPrec, Ssoil) 
swb.SoilEvaporation(DEF,PETs, Gsoil)

Arguments

NetPrec

A numeric vector of (daily) net precipitation (in mm of water).

Ssoil

Soil water storage capacity (can be referred to topsoil) (in mm of water).

DEF

Water deficit in the (topsoil) layer.

PETs

Potential evapotranspiration at the soil surface.

Gsoil

Gamma parameter (maximum daily evaporation).

Value

Function swb.SoilInfiltration a vector of the same length as NetPrec containing the daily amount of water that infiltrates into the soil (in mm of water). Function swb.SoilEvaporation returns the amount of water evaporated from the soil.

Details

See description of infiltration and soil evaporation processes in De Caceres et al. (submitted).

References

Boughton (1989). A review of the USDA SCS curve number method. - Australian Journal of Soil Research 27: 511-523.

De C<U+00E1>ceres M, Mart<U+00ED>nez-Vilalta J, Coll L, Llorens P, Casals P, Poyatos R, Pausas JG, Brotons L. (submitted) Coupling a water balance model with forest inventory data to evaluate plant drought stress at the regional level. Agricultural and Forest Meteorology.

Ritchie (1972). Model for predicting evaporation from a row crop with incomplete cover. - Water resources research.

See Also

swb

Examples

# NOT RUN {
SoilDepth = c(200,400,800,1200,1500)

#TOPSOIL LAYERS
d1 = pmin(SoilDepth, 300) #<300
#SUBSOIL LAYERS
d2 = pmax(0, pmin(SoilDepth-300,1200)) #300-1500 mm
#ROCK LAYER
d3 = 4000-(d1+d2) #From SoilDepth down to 4.0 m

TS_clay = 15
TS_sand = 25
SS_clay = 15
SS_sand = 25
RL_clay = 15
RL_sand = 25
TS_gravel = 20
SS_gravel = 40
RL_gravel = 95

Theta_FC1=soil.psi2theta(TS_clay, TS_sand, -33) #in m3/m3
Theta_FC2=soil.psi2theta(SS_clay, SS_sand, -33) #in m3/m3
Theta_FC3=soil.psi2theta(RL_clay, RL_sand, -33) #in m3/m3
pcTS_gravel = 1-(TS_gravel/100)
pcSS_gravel = 1-(SS_gravel/100)
pcRL_gravel = 1-(RL_gravel/100)
MaxVol1 = (d1*Theta_FC1*pcTS_gravel)
MaxVol2 = (d2*Theta_FC2*pcSS_gravel)
MaxVol3 = (d3*Theta_FC3*pcRL_gravel)
V = MaxVol1+MaxVol2+MaxVol3

par(mar=c(5,5,1,1), mfrow=c(1,2))
NP = seq(0,60, by=1)
plot(NP,swb.SoilInfiltration(NP, V[1]), type="l", xlim=c(0,60), ylim=c(0,60), 
     ylab="Infiltration (mm)", xlab="Net rainfall (mm)", frame=FALSE)
lines(NP,swb.SoilInfiltration(NP, V[2]), lty=2)
lines(NP,swb.SoilInfiltration(NP, V[3]), lty=3)
lines(NP,swb.SoilInfiltration(NP, V[4]), lty=4)
lines(NP,swb.SoilInfiltration(NP, V[5]), lty=5)
legend("topleft", bty="n", lty=1:5, legend=c(paste("d =", SoilDepth, "Vsoil =",round(V),"mm")))
plot(NP,NP-swb.SoilInfiltration(NP, V[1]), type="l", xlim=c(0,60), ylim=c(0,60), 
     ylab="Runoff (mm)", xlab="Net rainfall (mm)", frame=FALSE)
lines(NP,NP-swb.SoilInfiltration(NP, V[2]), lty=2)
lines(NP,NP-swb.SoilInfiltration(NP, V[3]), lty=3)
lines(NP,NP-swb.SoilInfiltration(NP, V[4]), lty=4)
lines(NP,NP-swb.SoilInfiltration(NP, V[5]), lty=5)
legend("topleft", bty="n", lty=1:5, legend=c(paste("d =", SoilDepth,"Vsoil =",round(V),"mm")))


# }