Parameter a recalculation formula (Subsidence Overlay)

The a parameter is recalculated yearly, to account for a changing climate. The new value for the a parameter is obtained by multiplying the original Parameter a is with a factor. This factor is calculated based on an interpolated average temperature for that year, a soil temperature factor, micro activity and an oxidation factor.

The value of the a parameter is updated each year as follows:

Delta temperature is calculated as:

$\Delta {T}=(T_{final}-T_{start})\cdot {\frac {y_{y}-y_{start}}{y_{final}-y_{start}}}\cdot f_{st}$

Delta micro activity is calculated as:

$\Delta {MA}=Q_{10}^{\Delta {T}/10.0}-1.0$

Delta subsidence is calculated as:

$\Delta {s_{sub}}=\Delta {MA}\cdot f_{ox}$

The new parameter a value for year y is calculated as:

$a_{y}=a_{0}\cdot (1.0+\Delta {s_{sub}})$

• $a_{y}$ = The a parameter for the current year.
• $a_{0}$ = The a parameter value at the start of the calculation, defined by PARAMETER_A.
• $y_{y}$ = The current year.
• $y_{start}$ = The start year of the simulation, defined by CLIMATE_START_YEAR.
• $y_{end}$ = The final year of the simulation, defined by the addition of the start year and YEARS.
• $T_{start}$ = The average temperature of the start year, defined by CLIMATE_START_TEMP.
• $T_{final}$ = The average temperature of the final year, defined by CLIMATE_FINAL_TEMP.
• $Q_{10}$ = The Q10 factor, configured as 3. This value is currently not adjustable.
• $f_{st}$ = Soil temperature factor, defined by CLIMATE_SOIL_TEMP_FACTOR.
• $f_{ox}$ = Oxidation factor, defined by CLIMATE_OXIDATION.

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Subsidence Module

Subsidence Overlay

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Parameter a recalculation • Ground water depth • Oxidation • Compaction • Subsidence • Indexation

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