# Model state/output¶

The AeoLiS model state is described by a collection of spatial grid variables with at least one value per horizontal grid cell. Specific model state variables can also be subdivided over bed composition layers and/or grain size fractions. All model state variables can be part of the model netCDF4 output. The current model state variables are listed below.

```
INITIAL_STATE = {
('ny', 'nx') : (
'uw', # [m/s] Wind velocity
'uws', # [m/s] Component of wind velocity in x-direction
'uwn', # [m/s] Component of wind velocity in y-direction
'tau', # [m/s] Wind shear velocity
'taus', # [m/s] Component of wind shear velocity in x-direction
'taun', # [m/s] Component of wind shear velocity in y-direction
'dtaus', # [-] Component of the wind shear perturbation in x-direction
'dtaun', # [-] Component of the wind shear perturbation in y-direction
'udir', # [rad] Wind direction
'zs', # [m] Water level above reference
'Hs', # [m] Wave height
'zne', # NEW! [m] Non-erodible layer
),
}
MODEL_STATE = {
('ny', 'nx') : (
'x', # [m] Real-world x-coordinate of grid cell center
'y', # [m] Real-world y-coordinate of grid cell center
# Gridparams
'xz', # [m] Real-world x-coordinate of grid cell center
'xu', # [m] Real-world x-coordinates of u-points
'xv', # [m] Real-world x-coordinates of v-points
'xc', # [m] Real-world x-oordinates of c-points
'yz', # [m] Real-world y-coordinate of grid cell center
'yu', # [m] Real-world y-coordinates of u-points
'yv', # [m] Real-world y-coordinates of v-points
'yc', # [m] Real-world y-coordinates of c-points
'ds', # [m] Real-world grid cell size in x-direction
'dn', # [m] Real-world grid cell size in y-direction
'dnz', # [m] Distances in n-direction
'dnu', # [m] Distances in n-direction
'dnv', # [m] Distances in n-direction
'dnc', # [m] Distances in n-direction
'dsz', # [m] Distances in s-direction
'dsu', # [m] Distances in s-direction
'dsv', # [m] Distances in s-direction
'dsc', # [m] Distances in s-direction
'dsdnz', # [m^2] Real-world grid cell surface area
'dsdnzi', # [m^-2] Inverse of real-world grid cell surface area
'dsdn', # [m^2] Real-world grid cell surface area
'dsdni', # [m^-2] Inverse of real-world grid cell surface area
'alfaz', # [rad] Real-world grid cell orientation around z
'alfau', # [rad] Real-world grid cell orientation around u
'alfav', # [rad] Real-world grid cell orientation around v
'alfa', # [rad] Real-world grid cell orientation #Sierd_comm in later releases this needs a revision
'zb', # [m] Bed level above reference
'S', # [-] Level of saturation
),
('ny','nx','nfractions') : (
'Cu', # [kg/m^2] Equilibrium sediment concentration integrated over saltation height
'Cuf', # [kg/m^2] Equilibrium sediment concentration integrated over saltation height, assuming the fluid shear velocity threshold
'Ct', # [kg/m^2] Instantaneous sediment concentration integrated over saltation height
'q', # [kg/m/s] Instantaneous sediment flux
'qs', # [kg/m/s] Instantaneous sediment flux in x-direction
'qn', # [kg/m/s] Instantaneous sediment flux in y-direction
'pickup', # [kg/m^2] Sediment entrainment
'w', # [-] Weights of sediment fractions
'w_init', # [-] Initial guess for ``w''
'w_air', # [-] Weights of sediment fractions based on grain size distribution in the air
'w_bed', # [-] Weights of sediment fractions based on grain size distribution in the bed
'uth', # [m/s] Shear velocity threshold
'uthf', # [m/s] Fluid shear velocity threshold
),
('ny','nx','nlayers') : (
'thlyr', # [m] Bed composition layer thickness
'moist', # [-] Moisure content
'salt', # [-] Salt content
),
('ny','nx','nlayers','nfractions') : (
'mass', # [kg/m^2] Sediment mass in bed
)
}
```