How is the resolution handled in Model
The model module is the refinement area from the map module to decide the refinement area and using geometrical expansion to set the resolution of the vertical cells. From the maximum number of cells and the amount of vertical cells the horizontal resolution for the refinement area is then set.
Vertical resolution:
In a windfield model we want high resolution close the the ground and lower resolution higher up in the atmosphere. We want to concentrate our computation close to the ground to capture as much effects as possible, while a lower resolution is sufficient close to the boundary layer where there is less effects.
To achieve this the numerical model is using geometrical expansion to decide the vertical size of the cells. This means that each cell is an=arn-1 where an is the n'th cell, a is the lowest cell and r is the 'Height Distributive Factor'.
Horizontal resolution:
The horizontal resolution can only be adjusted as a number of cells for the project, as well as the number of vertical cells.
The each vertical layer will then have the same number of cells and each layer will have #maxnumber of cells / vertical cells. Then the algorithm uses the available cells to create a constant mesh in the refinement area while the cell sizes are gradually larger in the buffer area (Area in the model around the refinement area)
Given an example project with:
- Refinement Area: 5000x5000 meters
- Vertical cells: 30
- Maximum number of cells: 100'000
Will have a resolution in the refinement zone approximately 180 m.
Increasing the number of maximum cells to 10'000'000 gets us a more useable resolution of 11.2 m in the refinement area
