Start | Index | Overview • PREV | UP | NEXT The actual \(CO_2\) is calculated by a linear function
\[ \begin{equation} CO_2(Year) = Slope \cdot (Year-StartYear) + StartValue \label{co2} \end{equation} \]The LUE is calculated in dependence of CO2 by the formula:
\[ \begin{eqnarray} \lambda & = & 100 g MJ^{-1} \\ LUE(CO_2) & = & \lambda \frac{CO_2}{CO_2 +b_1 e^{-b_2 CO_2}} \label{lue} \end{eqnarray} \]Finally the LUE-curve is stretched by a factor so that it meets the reference values
\[ \begin{eqnarray} f & = & \frac{LUE(ReferenceCO_2Value)}{ReferenceLueValue} \label{factor} \\ LUE & = & LUE(CO_2(Year)) \cdot f \label{finallue} \end{eqnarray} \]If you want to switch of the Co2 effect (e.g. if you use want to use the same solution with projects to calculate with and without Co2 effect), then you can parameterize the component, so that the calculated LUE corresponds the given one:
For clarity reasons however, it is recommended to use different solutions and to remove the simcomponent from the solution, if you don't want to calculate Co2 effect.
Stockle, C.O., Williams, J.R., Rosenberg, N.J., Jones, C.A., 1992. A method for estimating the direct and climatic effects of rising atmospheric carbon dioxide on growth and yield of crops, Agr. Sys. 38 (3), 225–238. See http://dx.doi.org/10.1016/0308-521X(92)90067-X
| Content Type | Name | Description | Data Type | Unit | Min Value | Max Value | Default Value |
|---|---|---|---|---|---|---|---|
| constant | cReferenceCo2Value | Used to rescale the curve to meet the reference point \(\eqref{factor}\). | DOUBLE | ppm | 0.0 | 2000.0 | 350.0 |
| constant | cReferenceLueValue | Used to rescale the curve to meet the reference point \(\eqref{factor}\). | DOUBLE | g/MJ | 0.0 | 10.0 | 3.0 |
| constant | cSlope | Slope to calculate CO2 amount of given year by linear function in \(\eqref{co2}\). | DOUBLE | ppm/a | -1000.0 | 1000.0 | 3.5 |
| constant | cStartValue | Reference CO2 amount of the StartYear, starting point of the line \(\eqref{co2}\) | DOUBLE | ppm | 0.0 | 2000.0 | 350.0 |
| constant | cStartYear | Reference year, starting point of the line \(\eqref{co2}\) | INT | a | 0 | 10000 | 1990 |
| constant | c_b1 | Parameter \(b_1\) to dertemine the shape of curve \(\eqref{lue}\) | DOUBLE | 1 | 0.0 | 1000000.0 | 6928.0 |
| constant | c_b2 | Parameter \(b_2\) to determine the shape of curve \(\eqref{lue}\) | DOUBLE | 1 | -10.0 | 10.0 | -0.0014 |
| out | LUE | Light use efficiency dependend on \(CO_2\) \(\eqref{finallue}\) | DOUBLE | g/MJ | 0.0 | 20.0 | - |