| 3 | | The canopy model embedded in PALM can be used to simulate the flow across vegetation canopies.\\ Thereby, the canopy is modeled as a porous viscous medium that removes momentum from the flow (according to Shaw & Schumann, 1992; Watanabe, 2004). The presentation [/wiki/doc/tut/job/canopy#Canopymodel "Canopy model"] provides detailed information on canopy-flow theory and the functionality of the canopy model. An example how to model the flow across a simple canopy block can be found under exercise [/wiki/doc/tut/job/canopy#Exercise9:Canopyflow "Canopy flow"].\\\\ |
| 4 | | Since revision 13XX all components of the canopy model are modularized into module [/browser/palm/trunk/SOURCE/plant_canopy_model.f90 plant_canopy_model_mod]. In this context, the steering parameters for the canopy model are, since revision 13XX, part of the new package {{{canopy_par}}}.\\\\ |
| 5 | | The package and the application of the canopy model is automatically activated by adding the NAMELIST {{{canopy_par}}} to your parameter file, subsequently to the NAMELIST {{{d3par}}}. |
| | 3 | |
| | 4 | The canopy model embedded in PALM can be used to simulate the effect of vegetation canopies on a turbulent flow.\\ Thereby, the canopy is modeled as a porous viscous medium that removes momentum from the flow (according to Shaw & Schumann, 1992; Watanabe, 2004). The presentation [/wiki/doc/tut/job/canopy#Canopymodel "Canopy model"] provides detailed information on canopy-flow theory and the functionality of the canopy model. An example on how to model the flow across a simple canopy block can be found under exercise [/wiki/doc/tut/job/canopy#Exercise9:Canopyflow "Canopy flow"].\\\\ |
| | 5 | |
| | 6 | Starting at revision 13XX (oder Release XX), all parts of the canopy-model-related PALM code are modularized in module [/browser/palm/trunk/SOURCE/plant_canopy_model.f90 plant_canopy_model_mod]. In this context, the newly created package {{{canopy_par}}} now contains all canopy-related input parameters. This means that the canopy model is now steered using the NAMELIST {{{canopy_par}}}, and no longer over the {{{inipar}}}-NAMELIST. Hence, in order to automatically enable the canopy model, NAMELIST {{{canopy_par}}} and the respective canopy parameters must be added to the parameter file ({{{_p3d}}}), subsequently to the NAMELIST {{{d3par}}}. |
| 21 | | Dimensionless coefficient for the construction of the leaf area density (lad) profile, using this beta probability density function (following XXcite):\\\\ |
| 22 | | {{{ |
| 23 | | #!Latex |
| 24 | | \[ lad(z/H) = , \] |
| 25 | | }}} |
| 26 | | This parameter steers together with [/wiki/doc/app/canpar#beta_lad beta_lad] the vertical distribution of leaf area within the canopy volume. [/wiki/doc/app/canpar#alpha_lad alpha_lad] can take values from XX to XX. Furthermore, the desired leaf area index (lai) has to be prescribed by setting [/wiki/doc/app/canpar#lai_beta lai_beta] to a non-zero value.\\\\ |
| 27 | | The leaf area density profile can also be constructed by prescribing vertical gradients ([/wiki/doc/app/canpar#lad_vertical_gradient_level lad_vertical_gradient_level], [/wiki/doc/app/canpar#lad_vertical_gradient lad_vertical_gradient]) of the leaf area density, starting from the prescribed surface value [/wiki/doc/app/canpar#lad_surface lad_surface]. |
| | 22 | Dimensionless coefficient required for the construction of the leaf area density (LAD) profile, using following beta probability density function (following XXcite):\\\\ |
| | 23 | {{{ |
| | 24 | #!Latex |
| | 25 | \[ f_{PDF}(\frac{z}{H},\alpha,\beta) = \frac{(\frac{z}{H})^{\alpha-1}\;(1-\frac{z}{H})^{\beta-1}}{\int_{0}^{1}\;(\frac{z}{H})^{\alpha-1}\;(1-\frac{z}{H})^{\beta-1}\;d(\frac{z}{H})}, \] |
| | 26 | }}} |
| | 27 | where ''z'' is the height above ground, ''H'' is canopy height, and alpha and beta are the coefficients to be presribed. The actual leaf area density values follow from: |
| | 28 | {{{ |
| | 29 | #!Latex |
| | 30 | \[ LAD(\frac{z}{H},\alpha,\beta) = LAI * f_{PDF}(\frac{z}{H},\alpha,\beta), \] |
| | 31 | }}} |
| | 32 | with LAI being the prescribed leaf area index [/wiki/doc/app/canpar#beta_lai \beta_lai] (LAI is the vertical integral over the LAD profile). |
| | 33 | |
| | 34 | [/wiki/doc/app/canpar#beta_lai \beta_lai] has to be set to a non-zero value in order to use the beta probability density function for the LAD-profile construction. |
| | 35 | [/wiki/doc/app/canpar#alpha_lad alpha_lad] steers together with [/wiki/doc/app/canpar#beta_lad beta_lad] the vertical distribution of leaf area within the canopy volume. [/wiki/doc/app/canpar#alpha_lad alpha_lad] can take values from XX to XX. \\\\ |
| | 36 | |
| | 37 | The LAD profile can also be constructed by prescribing vertical gradients ([/wiki/doc/app/canpar#lad_vertical_gradient_level lad_vertical_gradient_level], [/wiki/doc/app/canpar#lad_vertical_gradient lad_vertical_gradient]) of the leaf area density, starting from the prescribed surface value [/wiki/doc/app/canpar#lad_surface lad_surface]. |
| 40 | | Dimensionless coefficient for the construction of the leaf area density (lad) profile, using this beta probability density function (following XXcite):\\\\ |
| 41 | | {{{ |
| 42 | | #!Latex |
| 43 | | \[ lad(z/H) = , \] |
| 44 | | }}} |
| 45 | | This parameter steers together with [/wiki/doc/app/canpar#alpha_lad alpha_lad] the vertical distribution of leaf area within the canopy volume. [/wiki/doc/app/canpar#beta_lad beta_lad] can take values from XX to XX. Furthermore, the desired leaf area index (lai) has to be prescribed by setting [/wiki/doc/app/canpar#lai_beta lai_beta] to a non-zero value.\\\\ |
| | 50 | Dimensionless coefficient required for the construction of the leaf area density (LAD) profile, using following beta probability density function (following XXcite):\\\\ |
| | 51 | {{{ |
| | 52 | #!Latex |
| | 53 | \[ f_{PDF}(\frac{z}{H},\alpha,\beta) = \frac{(\frac{z}{H})^{\alpha-1}\;(1-\frac{z}{H})^{\beta-1}}{\int_{0}^{1}\;(\frac{z}{H})^{\alpha-1}\;(1-\frac{z}{H})^{\beta-1}\;d(\frac{z}{H})}, \] |
| | 54 | }}} |
| | 55 | where ''z'' is the height above ground, ''H'' is canopy height, and alpha and beta are the coefficients to be presribed. The actual leaf area density values follow from: |
| | 56 | {{{ |
| | 57 | #!Latex |
| | 58 | \[ LAD(\frac{z}{H},\alpha,\beta) = LAI * f_{PDF}(\frac{z}{H},\alpha,\beta), \] |
| | 59 | }}} |
| | 60 | with LAI being the prescribed leaf area index [/wiki/doc/app/canpar#beta_lai \beta_lai] (LAI is the vertical integral over the LAD profile). |
| | 61 | |
| | 62 | [/wiki/doc/app/canpar#beta_lai \beta_lai] has to be set to a non-zero value in order to use the beta probability density function for the LAD-profile construction. |
| | 63 | [/wiki/doc/app/canpar#beta_lad beta_lad] steers together with [/wiki/doc/app/canpar#alpha_lad alpha_lad] the vertical distribution of leaf area within the canopy volume. [/wiki/doc/app/canpar#beta_lad beta_lad] can take values from XX to XX. \\\\ |
| | 64 | |
