Ground evaporation formula (Water Overlay): Difference between revisions

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: <math>e_{w,t}</math> = the [[Evaporation_m_(Water_Overlay)|evaporation rate]] of the [[weather]] at time t
: <math>e_{w,t}</math> = the [[Evaporation_m_(Water_Overlay)|evaporation rate]] of the [[weather]] at time t
: <math>f_o</math> = the calculated feddes oxygen stress factor, calculated using the 3rd and 4th [[Root_depth_m_(Water_Overlay)|root depths]] and the feddes trapezium interpolation model and the ground water depth.
: <math>f_o</math> = the calculated feddes oxygen stress factor, calculated using the 3rd and 4th [[Root_depth_m_(Water_Overlay)|root depths]] and the feddes trapezium interpolation model and the ground water depth.
: <math>d_{b,c}</math> = The ground bottom distance of the cell c, defined by a [[Bottom distance prequel (Water Overlay)|Bottom distance prequel]] or a general [[Ground_bottom_distance_m_(Water_Overlay)|GROUND_BOTTOM_DISTANCE_M]] of the Water Overlay.
: <math>d_{s}</math> = the column height of the saturated zone covered by the roots
: <math>d_{r,n}</math> = the nth [[Root_depth_m_(Water_Overlay)|root depth value]].
: <math>f_s</math> = the calculated feddes saturated zone root update factor, calculated using the 1st and 2nd [[Root_depth_m_(Water_Overlay)|root depths]] and the feddes trapezium interpolation model and the ground water depth.
: <math>f_s</math> = the calculated feddes saturated zone root update factor, calculated using the 1st and 2nd [[Root_depth_m_(Water_Overlay)|root depths]] and the feddes trapezium interpolation model and the ground water depth.
: <math>d_{r,n}</math> = the nth [[Root_depth_m_(Water_Overlay)|root depth value]].
: <math>h_u</math> = the amount of water in the unsaturated zone.
: <math>h_u</math> = the amount of water in the unsaturated zone.
: <math>E_{max}</math> = the potential max evaporation
: <math>E_{max}</math> = the potential max evaporation
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: <math>E_{s}</math> = the evaporation in the saturated zone
: <math>E_{s}</math> = the evaporation in the saturated zone
: <math>E_{g}</math> = the total evaporation from the underground.
: <math>E_{g}</math> = the total evaporation from the underground.
: <math>d_{b,c}</math> = The ground bottom distance of the cell c, defined by a [[Bottom distance prequel (Water Overlay)|Bottom distance prequel]] or a general [[Ground_bottom_distance_m_(Water_Overlay)|GROUND_BOTTOM_DISTANCE_M]] of the Water Overlay.
 
: <math>d_{s}</math> = the column height of the saturated zone covered by the roots


==Related==
==Related==

Revision as of 13:02, 25 January 2024

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:

Potential evaporation saturated:

Evaporation saturated zone:

Evaporation total is the sum of evaporation in the saturated and unsaturated zone:

where

= the datum height of the surface of cell c, set by the elevation or a Terrain elevation prequel.
= the ground water level (datum height) at time t.
= the depth of the ground water level, which is equal to the column height of the unsaturated zone at time t.
= the transpiration factor of the buildings (plants) on the surface, or the surface terrain's transpiration factor if none present.
= the evaporation rate of the weather at time t
= the calculated feddes oxygen stress factor, calculated using the 3rd and 4th root depths and the feddes trapezium interpolation model and the ground water depth.
= The ground bottom distance of the cell c, defined by a Bottom distance prequel or a general GROUND_BOTTOM_DISTANCE_M of the Water Overlay.
= the column height of the saturated zone covered by the roots
= the nth root depth value.
= the calculated feddes saturated zone root update factor, calculated using the 1st and 2nd root depths and the feddes trapezium interpolation model and the ground water depth.
= the amount of water in the unsaturated zone.
= the potential max evaporation
= the evaporation in the unsaturated zone
= the potential evaporation in the saturated zone
= the evaporation in the saturated zone
= the total evaporation from the underground.


Related

The following topics are related to this formula.

Formulas
Groundwater level formula
Models
Underground model
Evaporation model