DEFINITION MODULE SoilWatBal;
(*******************************************************************
Module SoilWatBal (Version 1.0)
Copyright (c) 1995-2006 by Dimitrios Gyalistras and ETH Zurich.
Purpose Compute monthly and annual soil water balance
based on monthly temperature and precipitation
inputs.
Remarks All calculations are based on a simple bucket-type
model for soil water content.
This module was based on the submodels ForClim-E
of the forest patch models ForClim_V2.4.0.2 and
ForClim_V2.6.
Procedures ending with a "T" test the input
data for plausibility and correctness,
recognize missing input data as
DMConversions.UndefREAL's, and return
UndefREAL's if not succesful, but otherwise
perform exactly the same calculations as
their faster counterparts without a "T".
References:
Thornthwaite, C. W. & Mather, J. R., 1957.
Instructions and tables for computing potential
evapotranspiration and the water balance.
Publ. Climatol., 10: 183-311.
Fischlin, A., Bugmann, H. & Gyalistras, D., 1995.
Sensitivity of a forest ecosystem model to climate
parametrization schemes. Env. Poll., 87: 267-282.
Bugmann, H. & Cramer, W., 1998.
Improving the behaviour of forest gap models
along drought gradients.
ForestÊEcol.Ê&ÊManage. 103(2-3): 247-263.
Programming
o Design
Dimitrios Gyalistras 07/12/1995
o Implementation
Dimitrios Gyalistras 08/12/1995
ETH Zurich
Systems Ecology
CHN E 35.1
Universitaetstrasse 16
8092 Zurich
SWITZERLAND
URLs:
<mailto:RAMSES@env.ethz.ch>
<http://www.sysecol.ethz.ch>
<http://www.sysecol.ethz.ch/SimSoftware/RAMSES>
Last revision of definition: 21/09/1997 DG
*******************************************************************)
PROCEDURE GetSitePars(
(*PET1,2*) VAR latitude : REAL; (* geographical latitude [deg] *)
(*PET1,2*) VAR saModifier : REAL; (* slope/aspect modifier [--] *)
(*SWB 1 *) VAR fieldCap : REAL; (* field capacity [mm] *)
(*SWB 2 *) VAR bucketSize : REAL); (* bucket size [mm] *)
PROCEDURE SetSitePars( latitude : REAL;
saModifier : REAL;
fieldCap : REAL;
bucketSize : REAL;
VAR errTxt : ARRAY OF CHAR ): BOOLEAN;
(*
Get/Set site-specific parameters.
*)
(*----------------------------------------------------------------------------*)
TYPE
ValueType = ( cur, deflt, min, max );
PROCEDURE GetSWBPars( valueType : ValueType;
(*PET1,2*) VAR k1 : REAL; (* heat index multiplier [1/degC] *)
(*PET1,2*) VAR k2 : REAL; (* heat index exponent [-] *)
(*PET1,2*) VAR k3 : REAL; (* PET exponent coefficient [-] *)
(*PET1,2*) VAR k4 : REAL; (* -"- [-] *)
(*PET1,2*) VAR k5 : REAL; (* -"- [-] *)
(*PET1,2*) VAR k6 : REAL; (* -"- [-] *)
(*PET1,2*) VAR kPM : REAL; (* PET multiplier [-] *)
(*SWB 1 *) VAR k7 : REAL; (* used for calc. of water deficit [-] *)
(*SWB 1 *) VAR k8 : REAL; (* -"- [-] *)
(*SWB 2 *) VAR kIcpt : REAL; (* precip. fract. intercepted [-] *)
(*SWB 2 *) VAR kCw : REAL ); (* maximum transpiration rate [mm/month] *)
PROCEDURE SetSWBPars( k1, k2, k3, k4, k5, k6, kPM : REAL;
k7, k8, kIcpt, kCw : REAL;
VAR errTxt : ARRAY OF CHAR ): BOOLEAN;
(*
Get/set the parameters for the calculation of the soil water balance.
*)
(*----------------------------------------------------------------------------*)
PROCEDURE CalcHeatIndex ( VAR monTemper : ARRAY OF REAL; (* VAR for speed-up only *)
VAR heatIndex : REAL );
PROCEDURE CalcHeatIndexT( VAR monTemper : ARRAY OF REAL; (* VAR for speed-up only *)
VAR heatIndex : REAL;
VAR errTxt : ARRAY OF CHAR ): BOOLEAN;
(*
Computes heat index for calculation of potential evapotranspiration (PET).
*)
(*----------------------------------------------------------------------------*)
PROCEDURE CalcPET1( VAR monTemper : ARRAY OF REAL; (* monthly mean temperature [degC], VAR for speed-up only *)
heatIndex : REAL; (* heat index *)
VAR monPET : ARRAY OF REAL); (* potential evapotranspiration [mm/month] *)
PROCEDURE CalcPET1T( VAR monTemper : ARRAY OF REAL; (* VAR for speed-up only *)
heatIndex : REAL; (* heat index *)
VAR monPET : ARRAY OF REAL;
VAR errTxt : ARRAY OF CHAR ): BOOLEAN;
(*
Computes monthly PET for all months of the year according to ForClim_V2.4.0.2.
NOTE: This procedure is offered for compatibility with ForClim_V2.4.*.
It is however partially buggy, conceptually questionable, and numerically
sub-optimal, such that it should not be used normally.
See allso comments on CalcPET2 below.
*)
PROCEDURE CalcMonthlySWB1 (
monthNr : INTEGER;
initialSM : REAL; (* soil moisture at begin of month [mm] *)
initialSWD : REAL; (* soil water deficit at begin of month [mm] *)
monPET : REAL; (* monthly PET [mm/month] *)
monPrecip : REAL; (* monthly total precipitation [mm] *)
VAR monAET : REAL; (* monthly actual evapotranspiration [mm/month] *)
VAR newSM : REAL; (* soil moisture at end of month [mm] *)
VAR newSWD : REAL); (* soil water deficit at end of month [mm] *)
PROCEDURE CalcMonthlySWB1T(
monthNr : INTEGER;
initialSM : REAL;
initialSWD : REAL;
monPET : REAL;
monPrecip : REAL;
VAR monAET : REAL;
VAR newSM : REAL;
VAR newSWD : REAL;
VAR errTxt : ARRAY OF CHAR ): BOOLEAN;
(*
Computes monthly soil water balance according to ForClim_V2.4.0.2.
*)
PROCEDURE CalcAnnualSWB1 (
initialSM : REAL; (* soil moisture at begin of the year [mm] *)
VAR monPET : ARRAY OF REAL; (* monthly PET, VAR for speed-up only *)
VAR monPrecip : ARRAY OF REAL; (* monthly precip, VAR for speed-up only *)
VAR annPET : REAL; (* annual mean PET [mm/month] *)
VAR annAET : REAL; (* annual mean AET [mm/month] *)
VAR newSM : REAL); (* soil moisture at end of year [mm] *)
PROCEDURE CalcAnnualSWB1T(
initialSM : REAL;
VAR monPET : ARRAY OF REAL;
VAR monPrecip : ARRAY OF REAL;
VAR annPET : REAL;
VAR annAET : REAL;
VAR newSM : REAL;
VAR errTxt : ARRAY OF CHAR): BOOLEAN;
(*
Computes annual soil water balance according to ForClim_V2.4.0.2.
*)
(*----------------------------------------------------------------------------*)
PROCEDURE CalcPET2 ( monthNr : INTEGER;
heatIndex : REAL;
monTemper : REAL; (* monthly mean temperature [degC] *)
VAR monPET : REAL); (* potential evapotranspiration [mm/month] *)
PROCEDURE CalcPET2T( monthNr : INTEGER;
heatIndex : REAL;
monTemper : REAL;
VAR monPET : REAL;
VAR errTxt : ARRAY OF CHAR ): BOOLEAN;
(*
Computes monthly PET according to ForClim_V2.6.
The procedure differs from CalcPET1 in two respects:
(1) "latitude" is restricted to MIN(latitude,50.0). This was
a bug in CalcPET1, fixed by hb in ForClimE at 17/2/1995.
(2) The "heatIndex" presents in this procedure a site-specific
climatic parameter, i.e. it does not vary from year to year.
In CalcPET1 the heatIndex is determined anew for each individual
year, which is actually inconsistent with Thornthwait's original
parameterization.
(3) The auxiliary variable "heatIndex^3" is computed directly, not
using procedure "Power".
*)
PROCEDURE CalcMonthlySWB2 (
initialSM : REAL; (* soil moisture at begin of month [mm] *)
monPET : REAL; (* monthly PET [mm/month] *)
monPrecip : REAL; (* monthly total precipitation [mm] *)
VAR monAET : REAL; (* monthly actual evapotranspiration [mm/month] *)
VAR monEvapOffVeg : REAL; (* monthly evap. off vegetation [mm/month] *)
VAR monETFromSoil : REAL; (* monthly evapotransp. off the soil [mm/month] *)
VAR monRunoff : REAL; (* monthly runoff [mm/month] *)
VAR newSM : REAL); (* soil moisture at end of month [mm] *)
PROCEDURE CalcMonthlySWB2T(
initialSM : REAL;
monPET : REAL;
monPrecip : REAL;
VAR monAET : REAL;
VAR monEvapOffVeg : REAL;
VAR monETFromSoil : REAL;
VAR monRunoff : REAL;
VAR newSM : REAL;
VAR errTxt : ARRAY OF CHAR ): BOOLEAN;
(*
Computes monthly soil water balance according to ForClim_V2.6.
*)
PROCEDURE CalcAnnualSWB2 (
initialSM : REAL; (* soil moisture at begin of the year [mm] *)
VAR monPET : ARRAY OF REAL; (* monthly PET, VAR for speed-up only *)
VAR monPrecip : ARRAY OF REAL; (* monthly precip, VAR for speed-up only *)
VAR annPET : REAL; (* annual mean PET [mm/month] *)
VAR annAET : REAL; (* annual mean AET [mm/month] *)
VAR annEvapOffVeg : REAL; (* annual mean evap. off vegetation [mm/month] *)
VAR annETFromSoil : REAL; (* annual mean evapotransp. off the soil [mm/month] *)
VAR annRunoff : REAL; (* annual mean runoff [mm/month] *)
VAR newSM : REAL); (* soil moisture at end of year [mm] *)
PROCEDURE CalcAnnualSWB2T(
initialSM : REAL;
VAR monPET : ARRAY OF REAL;
VAR monPrecip : ARRAY OF REAL;
VAR annPET : REAL;
VAR annAET : REAL;
VAR annEvapOffVeg : REAL;
VAR annETFromSoil : REAL;
VAR annRunoff : REAL;
VAR newSM : REAL;
VAR errTxt : ARRAY OF CHAR): BOOLEAN;
(*
Computes annual soil water balance according to ForClim_V2.6.
*)
END SoilWatBal.
RAMSES
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