Climate related parameters

Sea-level (eustatic) forcing

Note

By default, the sea-level position in goSPL is set to 0 m. If you wish to set it to another position you can use the position key that changes the sea-level to a new value relative to sea-level. Another option consists in defining your own sea-level curve (curve) or using a published one (e.g. Haq curve for example).

Declaration example:

sea:
    position: 0.
    curve: 'sealevel.csv'

The sea-level declaration is defined with 2 optional parameters:

1. the relative sea-level position in meters (optional), its default value is set to 0.0

2. a sea-level curve e.g. a file containing 2 columns (time and sea-level position). Not required in case no sea-level fluctuations needs to be specified.

Important

The sea-level curve is defined as a 2 columns csv file containing in the first column the time in years (it doesn’t need to be regularly temporally spaced) and in the second the sea-level position for the given time. When goSPL interprets this file, it will interpolate linearly between the defined times to find the position of the sea-level for every time step.

Climatic (rainfall) forcing conditions

Declaration example:

climate:
    - start: 1000.
      map: ['rain_map','r']
    - start: 20000.
      uniform: 1.

The climatic forcing is defined in a similar fashion as the tectonic one. It is based on a sequence of events with each event starting at a given time (start in years) and corresponding to a given precipitation condition. This could either be an uniform rainfall over the entire mesh (uniform) or a precipitation mesh map. The rainfall values have to be in metres per year and the precipitation is updated at every time step (defined by dt).

Important

When defining a precipitation grid, one needs to use the npz format and needs to specify the key corresponding to the precipitation variable in the file. In the above example this key is 'r'. The precipitation grid needs to define values for all vertices in the mesh.

Orographic precipitation definition

Warning

The orographic precipitation is only available for 2D grids and will not be working for global models.

goSPL implements the Linear Theory of Orographic Precipitation following Smith & Barstad (2004).

Note

The model includes airflow dynamics, condensed water advection, and downslope evaporation. It consists of two vertically-integrated steady-state advection equations describing:

1. the cloud water density and

2. the hydrometeor density.

Solving these equations using Fourier transform techniques, derives a single formula relating terrain and precipitation.

Declaration example:

orography:
    regdx: 200.
    latitude: 40.0
    wind_speed: 10.0
    wind_dir: 0
    nm: 0.005
    env_lapse_rate: -4
    moist_lapse_rate: -7
    ref_density: 7.4e-3
    hw:  5000
    conv_time: 1000.
    fall_time: 1000.
    oro_precip_base: 7.0
    oro_precip_min: 0.01
    rainfall_frequency: 1

This part of the input file define the parameters for the orographic rain:

1. regdx: the resolution of the regular grid used to perform the orographic rain calculation.

Important

If both orographic rain and flexure are turned-on then the regdx values will have to be the same.

2. latitude: average latitude used to compute the Coriolis factors [degrees btw -90 and 90]; default 0

3. wind_speed: wind speed in m/s; default 10

4. wind_dir: wind direction [0: north, 270: west]; default 0

5. nm: moist stability frequency [1/s]; default 0.01

6. env_lapse_rate: environmental lapse rate [degrees Celsius/km]; default -4.0

7. moist_lapse_rate: moist adiabatic lapse rate [degrees Celsius/km]; default -7.0

8. ref_density: reference saturation water vapor density [kg/m^3]; default 7.4e-3

9. hw: water vapor scale height [m]; default 3400

10. conv_time: cloud water to hydrometeor conversion time [s]; default 1000

11. fall_time: hydrometeor fallout time [s]; default 1000

12. oro_precip_base: non-orographic, uniform precipitation rate [mm/h]; default 7.

13. oro_precip_min: minimum precipitation [mm/h] when precipitation rate <= 0; default 0.01

14. rainfall_frequency: number of storm of 1 hour duration per day; default 1

Warning

In case you missed it above: when flexure and orographic rain capabilities are defined in the same simulation, you will need to have the same grid resolution (regdx) for each definition.