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WorkingGroups/TOP/DS2017 (diff) – NEMO

Changes between Version 1 and Version 2 of WorkingGroups/TOP/DS2017

2017-12-11T11:42:24+01:00 (5 years ago)



  • WorkingGroups/TOP/DS2017

    v1 v2  
     1'''Extracted from''' ''"NEMO’s development strategy document (2017)" '' 
    14= '''Chapter 10 – The biogeochemical component of NEMO[[BR]]TOP interface for tracers and biogeochemistry''' = 
    25== 10.1 Scope == 
    912== 10.2 Main issues == 
    1014=== 10.2.1 Tracers vertical sinking === 
    1115Despite the large variety of advection and diffusion schemes made available through the OPA engine, the current NEMO code is still lacking a general scheme to deal with the vertical sinking of tracers in the pelagic environment. This is a key physical process that directly affects the spatio-temporal distribution of particulate suspended matter and the dynamics of phytoplanktonic groups, like e.g. diatoms. Among the large ensemble of approaches available from literature (Yool et al., 2013; Aumont et al, 2015; Vichi et al., 2015; Buthenschön et al., 2016) it is here necessary to identify the most suitable and up-to- date scheme to be included in TOP that will ensure an adequate balance between accuracy and computational efficiency. Furthermore, current schemes are mainly derived from typical advection schemes that were developed to handle transport by fluids. The potentially very high sinking speeds of particles (which can reach hundreds of meters per day) puts very high constraints on the timestep to respect the CFL criterion, especially where the vertical resolution is very high. To circumvent this constraint, time-splitting methods have been adopted by some biogeochemical models embedded in NEMO (Aumont et al., 2015). Yet, this can become every CPU intensive. Alternative solutions have been proposed in other modeling systems such as CROCO. These solutions will be investigated with care and if satisfying, the most appropriate one will be implemented in TOP.