# Depth Averaging Results

There are several ways in which to average 3D TUFLOWFV results over depth in order to visualise or output in a more manageable form. This guide explains the main types.

## Contents

## Depth Averaging Types

BLANK |
Sigma |
Depth |
Height |
Elevation |
Top |
Bottom |
---|---|---|---|---|---|---|

Datum |
Water Column |
Water Surface |
Bed Level |
Model Datum |
Water Surface |
Bed Level |

Units |
Scale |
Length Units |
Length Units |
Length Units |
No. Layers |
No. Layers |

### Sigma

**Sigma** depth averaging averages over the water column between 0 (bed level) and 1 (water surface). This allows for scaled differences between cells and can be used to extract such values as the average of *between a quarter and 3 quarters of the water column* - Sigma from 0.25 to 0.75

### Depth

**Depth** depth averaging specifies limits in length units (default meters) downwards from the water surface. This allows a user to pull out results for *between 6 12 meters below the water surface* - depth from 6 to 12m. The depth will be truncated at the bed level for any cells that may otherwise be exceeded.

### Height

**Height** depth averaging specifies limits in length units (default meters) upwards from the bed level. This allows a user to pull out results for *between 6 12 meters above the bed* - height from 6 to 12m. The height will be truncated at the water surface for any cells that may otherwise be exceeded.

### Elevation

**Elevation** depth averaging specifies limits in length units (default meters) between two values relative to the model's datum (ie. MSL or LAT). This allows a user to pull out results irrespective of water level change such as *Between -16 and -10m AMSL* - elevation from -16 to -10m. The limits will be truncated at the water surface and at the bed level for any cells that may otherwise be exceeded.

### Top Layer

**Top** depth averaging specifies limits in whole numbers of layers (from the model) from the top layer down. Single layers need the upper and lower limits to be the same. This allows a user to pull out results for the *top layer* - top layer from 1 to 1. The significance of this will depend on the type and combination of layers within the TUFLOWFV model. These limits will be truncated to the maximum number of layers in a cell for any cells that may otherwise be exceeded.

### Bottom Layer

**Bottom** depth averaging specifies limits in whole numbers of layers (from the model) from the bottom layer upwards. This allows a user to pull out results for the average of *between the second and fourth layers above the bed* - bottom layer from 2 to 4. As with Top layer depth averaging, the significance will depend on the types and combination of layers within the TUFLOWFV model. These limits will be truncated to the maximum number of layers in a cell for any cells that may otherwise be exceeded.

## MATLAB Usage

All of these depth averaging types are available when using the TUFLOWFV MATLAB tools.
Tools such as fvg_sheet and fvg_sheetvec have the properties *ref* and *range*.
a *ref* of 'height' and a *range* of [4 5], would depth average results between 4 and 5m above the bed level.

## TUFLOWFV Output

TUFLOWFV now allows depth averaged .nc and .dat output as well. See the TUFLOWFV Manual for further guidance.