Rainfall shuffler

CLEM.RainfallShuffler

Provides a random sequence of years to use to access pasture production

This component is provided to shuffle the rainfall sequence on an annual basis. This approach is a proxy for stochastic rainfall by keeping monthly rainfall together but randomly selecting the year to use. This assumes that there is relationship between years and so rainfall from year to year is independent. There is some evidence this is an appropriate response in northern Australia. This simple approach is provided for projects needing to investigate the impact of rainfall sequence and therefore pasture production on the system where a range of rainfall sequences are either not available or we are forced to use the historical rainfall sequence that was used to build the pasture production data-cube. You will need to run the model multiple times and use a random number seed in the Random number generator linked to the clock.

This component adds functionality to the Pasture data reader SQLite component.

This is an advanced feature for specific projects! Please ensure all assumptions behind this approach are relevant to your simulation.

The following parameters are used to define this component

The month that represents the start of the rainfall year. This allows a summer wet season (e.g. July-June) to be considered rather than a calendar year (January to December)

RequiredJanuarytoDecember

This property will ensure the rainfall is NOT shuffled for a specified iteration of a multi-run experiment simulation. This allows the historic (unshuffled) sequence of rainfall to be included in an experiment where a number of runs (iterations, set in Experiment factors and linked to Random number generator.Iteration property) are performed with a random realisation of annual rainfall.

To ensure rainfall shuffling isn't ignored unexpectedly, this value will default to -1 and therefore will never match the default Iteration value (0) when no Experiment is run with iterations, or any of the usual expected iteration values (>=0) unless the user sets iterations to start at -1.

Integerwithin range of iterations specified by experiment

The following components are required to use this activity

A Random number generator must be provided in the simulation tree for this component as a simulation-based random number sequence is required to shuffle the rainfall.

A Pasture data reader SQLite is the only data reader that supports shuffled rainfall.

See also