SPDM - Snow Probability Distributed Model – MATLAB Implementation

This repository contains a MATLAB implementation of a version of the Probability Distributed Moisture (PDM) model, a lumped conceptual hydrological model. The model employs a degree day approach for the snow module and is based on the PDM model's probability distribution of storage capacity for soil moisture accounting, linked to a routing component consisting of two parallel linear reservoirs.

The implementation follows the concepts described in:

• Moore, R. J. (1985), The probability-distributed principle and runoff production at point and basin scales, Hydrological Sciences Journal, 30 (2), 273–297.
• Moore, R. J. (2007), The PDM rainfall–runoff model, Hydrology and Earth System Sciences,11 (1), 483–499. doi: 10.5194/hess-11-483-2007.
• Book by TW, Rainfall-Runoff Modelling In Gauged And Ungauged Catchments?

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Contents

The repository includes MATLAB .m files implementing different components of the model:

• Snow module – snow_degree.m - uses degree day factor that defines the amount of snow melt per day per unit increase in temperature
• Soil moisture module – sma_pd3.m - uses PDM's probability-distributed storage capacity for soil moisture accounting; a Pareto distribution is assumed since it is the one most commonly used
• Routing module – r_2par.m - uses PDM's fraction of effective rainfall going through two parallel linear reservoirs for streamflow routing
• Performance metrics – NSE.m, and abias.m - functions for calculating Nash-Sutcliffe Efficiency (NSE) and absolute bias.
• Reservoir module – r_cres.m - simulation of conceptual reservoir behavior
• Latin hypercube sampling - lhcube.m - generates a Latin hypercube of N datapoints in the M-dimensional hypercube
• Info files – information about modules
• Input conditions and parameters – Step0input.m - function for creating and saving input structure.

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Model Inputs and Outputs

• Inputs:

  • Daily precipitation
  • Daily temperature
  • Potential evapotranspiration

• Output:

  • Simulated streamflow at the catchment outlet

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How to Use

1. Clone the repository:

   git clone https://github.com/thorsten1971/pdm-matlab.git

2. Open MATLAB and add the repository folder to the MATLAB path
3. Modify input files and parameter settings as needed for your catchment