SAGA-GIS Tool Library Documentation (v7.8.2)

Tool 01: A Simple Litter System

A simple litter system model using the euler method. Carbon storage C is calculated in dependency of litter fall rate (Cinput) and rate constant for litter loss (Closs) as:
C(t + 1) = C(t) + (Cinput - Closs * C(t)) * dt

Typical values:

- Tropical Rainforest:
-- Litter fall rate: 500 [g/m2/a]
-- Litter loss rate: 2.0 [1/a]

- Temperate forest:
-- Litter fall rate: 240 [g/m2/a]
-- Litter loss rate: 0.4 [1/a]

- Boreal forest:
-- Litter fall rate: 50 [g/m2/a]
-- Litter loss rate: 0.05 [1/a]

Reference:
Hugget, R.J. (1993): 'Modelling the Human Impact on Nature', Oxford University Press.

Parameters

 NameTypeIdentifierDescriptionConstraints
OutputResultsTable, outputTABLE--
OptionsTime SpanFloating pointTIME_SPAN-Minimum: 0.000000
Default: 100.000000
Time Interval [a]Floating pointTIME_STEP-Minimum: 0.000000
Default: 0.100000
Initial Litter Storage [g/m²]Floating pointC_INIT-Minimum: 0.000000
Default: 0.000000
Litterfall Rate [g/m²/a]Floating pointC_INPUT-Minimum: 0.000000
Default: 240.000000
Rate Constant for Litter Loss [1/a]Floating pointC_OUTPUT-Minimum: 0.000000
Default: 0.400000

Command-line

Usage: saga_cmd sim_ecosystems_hugget 0 [-TABLE <str>] [-TIME_SPAN <double>] [-TIME_STEP <double>] [-C_INIT <double>] [-C_INPUT <double>] [-C_OUTPUT <double>]
  -TABLE:<str>       	Results
	Table, output
  -TIME_SPAN:<double>	Time Span
	Floating point
	Minimum: 0.000000
	Default: 100.000000
  -TIME_STEP:<double>	Time Interval [a]
	Floating point
	Minimum: 0.000000
	Default: 0.100000
  -C_INIT:<double>   	Initial Litter Storage [g/m²]
	Floating point
	Minimum: 0.000000
	Default: 0.000000
  -C_INPUT:<double>  	Litterfall Rate [g/m²/a]
	Floating point
	Minimum: 0.000000
	Default: 240.000000
  -C_OUTPUT:<double> 	Rate Constant for Litter Loss [1/a]
	Floating point
	Minimum: 0.000000
	Default: 0.400000