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:

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

Delta micro activity is calculated as:

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

Delta subsidence is calculated as:

$\mathrm{\Delta }S=\mathrm{\Delta }MA\cdot f_{ox}$

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

$a_y=a_0\cdot (1+\mathrm{\Delta }S)$

• $a_y$ = The a parameter for the current year.
• $a_0$ = The a parameter value at the start of the calculation, defined by Parameter a.
• $T_y$ = The interpolated average temperature for the calculation in the current year.
• $y_y$ = 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
• $T_y$ = The interpolated average temperature for the calculation in the current year.
• $f_{st}$ = 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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