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solvers:surfaceboundaryenthalpy [2020/05/15 13:13] adriengilbert |
solvers:surfaceboundaryenthalpy [2020/05/18 11:06] (current) adriengilbert |
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* **Solver Fortran File:** '' | * **Solver Fortran File:** '' | ||
- | * **Solver Name:** '' | + | * **Solver Name:** '' |
- | * **Required Output Variable(s): | + | * **Required Output Variable(s): |
+ | * **Optional Output Variable(s): | ||
* **Required Input Variable(s): | * **Required Input Variable(s): | ||
* **Input Data:** Daily air temperature timeserie | * **Input Data:** Daily air temperature timeserie | ||
* **Optional Input Data: | * **Optional Input Data: | ||
+ | |||
+ | For vertically structured 3D mesh only. Works in serial and parallel. | ||
==== General Description ==== | ==== General Description ==== | ||
- | SurfBoundarySolver | + | SurfEnthBoundarySolver |
+ | |||
+ | The solver uses the provided air temperature (and precipitation) daily record to compute the associated mean surface characteristic of the glacier over the time period covered by the provided data time-serie. It can output the following variables: | ||
+ | |||
+ | - '' | ||
+ | - '' | ||
+ | - '' | ||
+ | - '' | ||
+ | - '' | ||
+ | - '' | ||
+ | - '' | ||
+ | - '' | ||
+ | - '' | ||
+ | - '' | ||
+ | |||
+ | The mass balance model is based on a degree day model that takes into account potential solar radiation. Mean Enthalpy at 10m-depth (bellow active layer), is computed by solving the heat equation on a 1D vertical profile forced by a mean annual cycle of air temperature and precipitation determined from the data. This is done for each surface nodes using a Crank-Nicholson scheme on a 6 cm resolution grid at daily time-step. It takes into account of seasonal change of the density profile and allow percolation of water only where density is lower than 800 kg/m3. More details about the model can be found in: | ||
+ | |||
+ | Gilbert, A., Sinisalo, A., Gurung, T. R., Fujita, K., Maharjan, S. B., Sherpa, T. C., & Fukuda, T. (2020). The influence of water percolation through crevasses on the thermal regime of a Himalayan mountain glacier. The Cryosphere, 14(4), 1273–1288. https:// | ||
+ | |||
+ | ==== SIF contents ==== | ||
+ | |||
+ | The parameters are set in the constant section of the sif file : | ||
+ | |||
+ | < | ||
+ | Constants | ||
+ | |||
+ | rho_surf = real 350.0 ! Snow surface density | ||
+ | rho_ice = real 917.0 ! Ice density | ||
+ | rho_w = real 1000.0 ! Water density | ||
+ | Sr = real 0.005 ! Residual water saturation in Snow/Firn | ||
+ | T_ref_enthalpy = real 200.0 ! Use to compute Surf Enth (see Enthalpy solver) | ||
+ | L_heat = real 334000.0 | ||
+ | |||
+ | AirTemperatureFile = File " | ||
+ | PrecipFile = File " | ||
+ | |||
+ | Precip = real 0.300 !Mean annual precipitation if PrecipFile not provided | ||
+ | TempCorrec= real -0.12 !Possibility of shifting temperature to get steady state mass balance for example (optional) | ||
+ | PrecipCorrec = real 1.0 !Possibility of adding a correcting factor on precipitation if PrecipFile provided (optional) | ||
+ | |||
+ | GradTemp = real 0.0065 !Air temperature Lapse Rate (K m^-1) | ||
+ | GradPrecip= real 0.001 !Precipitation Lapse Rate (% m^-1) | ||
+ | z_temp = real 5310.0 !Elevation of temperature measurement from AirTemperatureFile (m) | ||
+ | z_precip = real 5310.0 !Elevation of Precipitation measurement (m) | ||
+ | |||
+ | RadFact_ice = real 0.0000925 ! Melting factor for ice from radiation | ||
+ | RadFact_snow = real $0.0000925/ | ||
+ | Deg_jour = real 0.0114 ! Melting factor from air temperature | ||
+ | |||
+ | seuil_precip = real 2.0 !Rain/ | ||
+ | seuil_fonte = real 0.0 !Melting air temperature threshold (degree C) | ||
+ | |||
+ | firn_param = real 30.0 ! Firn densification factor (yr) | ||
+ | super_ice = real 0.15 ! Superimposed ice factor | ||
+ | |||
+ | Latitude = real 28.82 !Latitude (degree) to compute Potential Solar Radiation | ||
+ | |||
+ | !Possibility to export 1D profile simulation at one node of coordinate (X_output1D, | ||
+ | X_output1D = real x_coordinate | ||
+ | Y_output1D = real y_coordinate | ||
+ | |||
+ | |||
+ | End | ||
+ | </ | ||
+ | |||
+ | The solver needs output from the FlowDepth Solver : | ||
+ | |||
+ | < | ||
+ | Solver 1 | ||
+ | |||
+ | Equation = " | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | ! this sets the direction | ||
+ | ! -1 is negative z-direction (upside down) | ||
+ | ! +1 is positive (downside up) | ||
+ | | ||
+ | Calc Free Surface = Logical True | ||
+ | | ||
+ | End | ||
+ | </ | ||
+ | |||
+ | The solver is called with the following: | ||
+ | |||
+ | < | ||
+ | Solver 2 | ||
+ | |||
+ | Equation = SurfBoundary | ||
+ | Variable = Surf Enth | ||
+ | Variable DOFs = 1 | ||
+ | procedure = " | ||
+ | |||
+ | ! The following variables declaration are optional: | ||
+ | |||
+ | Exported Variable 1 = String "Mass Balance" | ||
+ | Exported Variable 1 DOFs = 1 | ||
+ | |||
+ | Exported Variable 2 = String " | ||
+ | Exported Variable 2 DOFs = 1 | ||
+ | |||
+ | Exported Variable 3 = String " | ||
+ | Exported Variable 3 DOFs = 1 | ||
+ | |||
+ | Exported Variable 4 = String " | ||
+ | Exported Variable 4 DOFs = 1 | ||
+ | |||
+ | Exported Variable 5 = String " | ||
+ | Exported Variable 5 DOFs = 1 | ||
+ | |||
+ | Exported Variable 6 = String " | ||
+ | Exported Variable 6 DOFs = 1 | ||
+ | |||
+ | Exported Variable 7 = String " | ||
+ | Exported Variable 7 DOFs = 1 | ||
+ | |||
+ | Exported Variable 8 = String " | ||
+ | Exported Variable 8 DOFs = 1 | ||
+ | |||
+ | Exported Variable 9 = String " | ||
+ | Exported Variable 9 DOFs = 1 | ||
+ | |||
+ | End | ||
+ | </ | ||
+ | |||
+ | Boundary Condition to setup Dirichlet condition for the Enthalpy Solver: | ||
+ | |||
+ | < | ||
+ | ! Upper Surface | ||
+ | Boundary Condition 2 | ||
+ | Target Boundaries = 2 | ||
+ | |||
+ | Depth = real 0.0 | ||
+ | Enthalpy_h = Equals Surf Enth | ||
+ | |||
+ | End | ||
+ | </ | ||
+ | |||
+ | ==== Examples ==== | ||
+ | An example solving for the enthalpy within the Rika Samba Glacier using the SurfEnthBoundarySolver can be found in '' | ||
- | The solver uses the provided air temperature (and precipitation) daily record to compute the associated mean surface characteristic of the glacier over the time period covered by the provided data time-serie. It outputs the following variables: | + | ==== Reference ==== |
- | - < | + | Gilbert, A., Sinisalo, A., Gurung, T. R., Fujita, K., Maharjan, S. B., Sherpa, T. C., & Fukuda, T. (2020). The influence of water percolation through crevasses on the thermal regime of a Himalayan mountain glacier. The Cryosphere, 14(4), 1273–1288. https://doi.org/10.5194/tc-14-1273-2020 |
- | - Surf Enth (J kg^{-1}) : Enthalpy value bellow active layer. Can be use as a Dirichlet condition in the Enthalpy Solver | + | |
- | - Densi (kg m^{-3}): Density field in 3D | + | |
- | - Firn (m w. eq.) : Firn thickness | + | |
- | - Melting (m w.eq. yr^{-1}) : Surface melting | + | |
- | - Refreeze (m w.eq. yr^{-1}) : Amount of refreezing | + | |
- | - Accu (m w.eq. yr^{-1}) : Snow accumulation | + | |
- | - Rad_fact (m w.eq. (W m^{-2})^{-1}) | + | |
- | - Rain (m w.eq. yr^{-1}) : Amount of rain | + | |
- | | + | |