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start:hype_model_description:hype_np_riv_lake [2018/11/16 15:46] cpers [Basic assumptions] |
start:hype_model_description:hype_np_riv_lake [2019/09/30 10:07] cpers [Sedimentation/Resuspension] |
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===== Primary production and mineralization ===== | ===== Primary production and mineralization ===== | ||
- | Primary production in lakes and rivers is a source of organic nitrogen and particulate phosphorus and a sink for inorganic nitrogen and soluble reactive phosphorus in the model. The reverse is true for mineralization. The processes is modelled together and only one is active at the time. Primary production and mineralization are controlled by two temperature functions. The first (//tmpfcn1//) is solely dependent on the water temperature (//T<sub>w</sub>//). It simulates the increased activity at warmer temperatures. The second (//tmpfcn2//) governs the relationship between primary production and mineralization and determines which one dominates. Net primary production is highest in spring (northern hemisphere) and changes into net mineralization when the temperature //T10// is less than the temperature //T20// in autumn. These two temperatures are calculated as the average water temperature of 10 and 20 days. | + | Primary production in lakes and rivers is a source of organic nitrogen and particulate phosphorus and a sink for inorganic nitrogen and soluble reactive phosphorus in the model. The reverse is true for mineralization. The processes are modelled together and only one is active at the time. Primary production and mineralization are controlled by two temperature functions. The first (//tmpfcn1//) is solely dependent on the water temperature (//T<sub>w</sub>//). It simulates the increased activity at warmer temperatures. The second (//tmpfcn2//) governs the relationship between primary production and mineralization and determines which one dominates. Net primary production is highest in spring (northern hemisphere) and changes into net mineralization when the temperature //T10// is less than the temperature //T20// in autumn. These two temperatures are calculated as the average water temperature of 10 and 20 days. |
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===== Sedimentation/Resuspension ===== | ===== Sedimentation/Resuspension ===== | ||
- | Sedimentation in lakes is a sink for particulate phosphorus (PP) and organic nitrogen (ON), as well as for suspended sediments (SS) and algae (AE). Sedimentation (//sed//, //m/day//) is calculated as a function of concentration (//conc//) in the lake and lake area (//area//). The sedimentation rate (//par<sub>sed</sub>//) is given by parameters (//sedon//, //sedpp//, //sedss//, //sedae//) which are generic, but ON and PP sedimentation can be specified for each lake. The concentration used in the equation may be limited (//lim//) by general parameters (//limsedON//, //limsedPP//, //limsedSS//), but not for AE (//lim//=0). | + | Sedimentation in lakes is a sink for particulate phosphorus (PP) and organic nitrogen (ON), as well as for suspended sediments (SS) and algae (AE). Sedimentation (//sed//, //kg/day//) is calculated as a function of concentration (//conc//) in the lake and lake area (//area//). The sedimentation rate (//par<sub>sed</sub>//) is given by parameters (//sedon//, //sedpp//, //sedss//, //sedae//) which are generic, but ON and PP sedimentation can be specified for each lake. The concentration used in the equation may be limited (//lim//) by general parameters (//limsedON//, //limsedPP//, //limsedSS//), but not for AE (//lim//=0). |
<m> sed = par_sed * (conc-lim) * area </m> | <m> sed = par_sed * (conc-lim) * area </m> |