# tracers2D Section

This section configures **2D tracer simulations**, including **diffusion**, **advection**, and **input files**.

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 | **Parameter** | **Description** |
 |---------------|----------------|
 | `tracers_computation` | Flag to enable/disable 2D tracer computations (`TRUE`, `FALSE`). |
 | `start` | Start time for tracer simulation (default: `0.0`, units to be verified). |
 | `interval` | Interval for tracer output (default: `1800 s`). |
 | `time_integration` | Time integration scheme for tracers (`FORWARD`, `LEAPFROG`, `EULER-BF`). |
 | `input_file` | Input file for tracers (default: `tracers.dat`). |
 | `initialisation_file` | Initialization file for tracers. |
 | `horizontal_diffusion_mode` | Mode for horizontal diffusion (`DEFAULT`, `NONE`, `SMAGORINSKY`, `CONSTANT`, `UPWINDING`). |
 | `horizontal_diffusion_coefficient` | Coefficient for horizontal diffusion (default: `0.0 m²/s`). |
 | `smagorinsky_coefficient` | Smagorinsky coefficient for tracers (default: `2.8`, dimensionless). |
 | `upwind_coefficient` | Upwind coefficient for tracers (default: `0.1`, dimensionless). |