Ground evaporation formula (Water Overlay): Difference between revisions
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Feddes oxygen stress factor: | Feddes oxygen stress factor: | ||
<math>f_o = | <math>f_o = | ||
\begin{cases} | \begin{cases} | ||
1.0 & \text{if } d_{gw,t} \text{ is } | 1.0 & \text{if } d_{gw,t} \text{ is } \geq d_{r,3} \\ | ||
\frac{d_{gw,t} - d_{r,4}}{d_{r,3} - d_{r,4}} & \text{if } d_{gw,t} \text{ is } | \frac{d_{gw,t} - d_{r,4}}{d_{r,3} - d_{r,4}} & \text{if } d_{gw,t} \text{ is } \geq d_{r,4} \\ | ||
0.0 & \text{otherwise} | 0.0 & \text{otherwise} | ||
\end{cases} | \end{cases} | ||
</math> | </math> | ||
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<math>f_s = | <math>f_s = | ||
\begin{cases} | \begin{cases} | ||
0.0 & \text{if } d_{gw,t} \text{ is } >= d_{r,1 | 0.0 & \text{if } d_{gw,t} \text{ is } >= d_{r,1} \\ | ||
1.0 - \frac{d_{gw,t} - d_{r,2}}{d_{r,1} - d_{r,2}} & \text{if } d_{gw,t} \text{ is } >= d_{r,2 | 1.0 - \frac{d_{gw,t} - d_{r,2}}{d_{r,1} - d_{r,2}} & \text{if } d_{gw,t} \text{ is } >= d_{r,2} \\ | ||
1.0 & \text{otherwise} | 1.0 & \text{otherwise} | ||
\end{cases} | \end{cases} | ||
</math> | </math> | ||
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Evaporation saturated: | Evaporation saturated: | ||
<math>h_{s} = w_{g,t} - ( b_{s} - d_{gb} )</math> | <math>h_{s} = w_{g,t} - ( b_{s} - d_{gb} )</math> | ||
<math>h_{r} = max( 0.0 , w_{g,t} - ( b_{s} - d_{r,1} ))</math> | <math>h_{r} = max( 0.0 , w_{g,t} - ( b_{s} - d_{r,1} ))</math> | ||
<math>E_{sp} = (E_{max} - E_{u}) \cdot f_s</math> | <math>E_{sp} = (E_{max} - E_{u}) \cdot f_s</math> | ||
<math>E_{s} = max (0.0 , min ( E_{sp}, h_{s}\cdot f_{gw}, h_r \cdot f_{gw}</math> | <math>E_{s} = max (0.0 , min ( E_{sp}, h_{s}\cdot f_{gw}, h_r \cdot f_{gw}</math> | ||
Revision as of 13:02, 25 February 2021
Underground evaporation is calculated per cell.
For all underground evaporation calculation, the ground water depth at time t is used.
Feddes oxygen stress factor:
Feddes saturated zone root update factor:
Max potential evaporation:
Evaporation unsaturated: Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle E_{u} = \begin{cases} 0.0 & \text{if } d_{us} \text{ is } <= 0.0} \\ min(E_{max}, h_u \cdot \frac{d_{r,1}}{d_{gw,t}})& \text{otherwise} \\ \end{cases} }
Evaporation saturated:
Evaporation total is the sum of evaporation in the saturated and unsaturated zone:
where
- is the datum height of the surface.
- is the underground water level.
- is the column height of the unsaturated zone.
- is the transpiration factor of the buildings (plants) on the surface, or the surface terrain's
[Terrain_water_evaporation_factor_(Water_Overlay)|transpiration factor]] if none present.
- is the evaporation rate of the weather at time t
- is the feddes oxygen stress factor, calculated using the 3rd and 4th root depths and the feddes trapezium interpolation model and the ground water depth.
Related
The following topics are related to this formula.
- Formulas
- Groundwater level formula
- Models
- Underground model
- Evaporation model
- Models
- Surface • Ground • Rain • Evaporation • Infiltration • Elevation • Breach • Sewer • Storage • Tracer flow • Border • Order
- Model formulas
- Timestep • Season • Surface water level • Groundwater level
- Flow formulas
- Surface flow • Surface infiltration • Ground flow • Ground infiltration • Surface evaporation • Ground evaporation • Ground bottom flow
- Hydraulic structure formulas
- Culvert • Weir • Breach growth • Breach flow • Pump • Sewer Overflow • Inlet • Drainage
- Related