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}}) $

where

$ a_{y} $ = The a parameter for the current year.

$ a_{0} $ = The a parameter value at the start of the calculation, defined by the model attribute A.

$ y_{y} $ = The current year. The first year is defined by START_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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