User:Tgibbs/Workflows

SCHISM in SMS

SCHISM Model Overview

SCHISM (Semi-implicit Cross-scale Hydroscience Integrated System Model) is a flexible, open-source modeling system used to simulate a range of hydrodynamic and environmental processes. It is integrated with the Aquaveo Surface-water Modeling System (SMS), supporting 2D and 3D simulations.

Interface Overview

The SCHISM interface within SMS contains these key components:

• Model Control Dialog - Main interface for defining simulation parameters.
• Project Explorer - Organizes model coverages, simulations, and files.
• Map and Mesh Views - Interactive visualization of spatial data and mesh structures.
• Simulation Menu and Toolbar - Tools for creating, linking, running, and managing simulations.

SCHISM Model Control Dialog

The Model Control dialog in SMS organizes simulation setup into four main tabs:

• Sections list – A list of sections that can be turned on or off:
  • CORE – Turn on to make the CORE section visible.
  • OPT – Turn on to make the OPT section visible.
  • SCHOUT – Turn on to make the SCHOUT section visible.
  • OTHER – Turn on to make the OTHER section visible.

CORE

Exmaple of the CORE section in the SCHISM Model Control dialog

This section includes the following options.

• Pre-preprocessing flag (pre) – Pre-processing flag (1 = on; 0 = off). ipre=0: normal run. The pre-processing flag is used for checking integrity of the horizontal grid and some inputs.
• Barotropic flag (ibc) – If ibc=1, a barotropic model is used, and the transport equation may (when ibtp=1) or may not (when ibtp=0) be solved; in the former case, S and T are treated as passive tracers.
• Baroclinic flag (ibtp) – If ibc=0, a baroclinic model is used and regardless of the value for ibtp, the transport equation is solved.
• Total simultion time in days (rnday) – The total simulation time designated in days.
• Time step in seconds (dt) – Time step in seconds. This is the main time step in SCHISM.
• msc2 –
• mdc2 –
• # of tracers for GEN (ntracer_gen) –
• # of tracers for AGE (ntracer_age) –
• # of tracers for SED3D (sed_class) –
• # of tracers for EcoSim (eco_class) –
• Global output step spool (nspool) –
• Global stack spool (ihfskip) –

OPT

Exmaple of the OPT section in the SCHISM Model Control dialog

This section contains the following options:

• Start Time / End Time - Simulation duration (Format: YYYY-MM-DD HH:MM:SS).
• Time Step - Time step length in seconds.
• Number of Time Steps - Number of time steps to run.
• Restart Option - Choose to restart or continue from a saved state.
• Coordinate System - Defines the spatial reference for input and output.

SCHOUT

Exmaple of the SCHOUT section in the SCHISM Model Control dialog

• Hydrodynamics Mode - Select between 2D or 3D simulation.
• Salinity and Temperature - Toggle scalar transport of salinity and temperature.
• Sediment Transport - Enable sediment transport modeling.
• Wind Forcing - Input wind data through time series or constants.
• Heat Exchange - Enable heat flux between water surface and atmosphere.

OTHER Tab

• Time Integration Scheme - Choose time stepping method (semi-implicit or explicit).
• Solver Iterations - Set max number of iterations per time step.
• Convergence Criteria - Set tolerance for solver convergence.
• Slope Limiters - Control gradient steepness for stability.
• Courant Control - Apply Courant number limits for stability.

Coverages and Arc Properties

Coverages define geographic features, such as boundaries and forcing conditions. There are two official types of coverages in SCHISM. These define different spatial and boundary configurations.

• Boundary Conditions
• Upwind Solver Coverage

Boundary Conditions Coverage

This coverage is used to specify boundary-related input data for the simulation. It includes settings for external forcing, discharge, and meteorological conditions.

• Open Boundary: Designates boundaries with external forcing (e.g., tides).
• River Inflow: Assigns river discharge to specified boundary arcs.
• Meteorological Forcing: Enables surface forcing from wind or heat fluxes.
• Land Boundaries - Represent no-flow or wall-type boundaries.
• Tidal/Stage Boundaries - Input water level conditions (e.g., time series, harmonic constituents).
• Flow Boundaries - Set discharge inflows/outflows.
• Scalar Boundaries - Input scalar values (salinity, temperature).

Each boundary condition allows for specific input fields such as time series assignment, units, and reference elevation.

Arc Properties

Example of the SCHISM Arc Properties dialog

Arc properties specify flow and connection rules for arcs within SCHISM coverages. Each arc within a boundary condition coverage has properties:

• Boundary Type: Defines if the arc is an inflow, outflow, or internal open boundary.
• Flow Rate: Sets a fixed or time-varying inflow rate.
• Elevation Constraint: Applies elevation-based rules to arc segments.
• Arc Type - Defines arc behavior (land, tidal, flow, scalar).
• Input Values - Define constant or time-series input values for elevation, discharge, etc.

Simulation Menu

Menu Controls

SCHISM Simulation Menu Options

Menu Option	Description
New Simulation	Initializes a new SCHISM simulation item.
Load Simulation	Opens a pre-existing SCHISM simulation.
Delete Simulation	Removes the selected simulation from the project.
Link Coverage	Associates map coverages (e.g., boundary, materials) with the simulation.
Run Simulation	Executes the simulation using defined model parameters.
Export Files	Writes all SCHISM input files needed for a run.
Simulation Properties	Opens the Model Control dialog for configuration.
Save Simulation	Saves current settings and configuration.

Resources

• SCHISM Manual