Changes between Version 7 and Version 8 of 2020WP/TOP-01_rlod_Antarctic_ice_Sheet_Fe_Source

2020-05-04T17:57:43+02:00 (7 months ago)


  • 2020WP/TOP-01_rlod_Antarctic_ice_Sheet_Fe_Source

    v7 v8  
    3838A sediment content associated to a solubility fraction of sediment Fe is added to the freshwater fluxes of iceberg and ice shelf. For ice shelf, the parameterization of Mathiot et al. (2017) is used for the distribution of Fe throughout the water column. For iceberg, a homogeneous distribution until 120 m of depth is applied. 
    40 modified routines : 
     40File dependency: feshwater fluxes from ice shelf and iceberg from observations and model climatology: 
     44This file dependency didn’t exist for ORCA2 grid. I have build one but roughly interpolated. Another issue with the ORCA2 configuration is that the grid is not extended in the Antarctic. There is no representation of ice shelf cavities which are needed to model the distribution of freshwater flux under ice shelves with the parameterization of Mathiot et al. (2017) used in the present development. 
     46Consequently, this external of source Fe will be disabled in the ORCA2 configuration. 
     48Two options are possible to implement the development of the AIS Fe source: 
     49- Activation in PISCES: namelist_pisces (originally developed) 
     50- Activation in TOP: namelist_top 
     52We opt for the generic solution by creating a trc_ais routine controllable in the TOP module and allowing to adjust the concentration of Fe and of other nutrients as well as DIC and Alkalinity in icebergs and ice shelves through a loop over all the biogeochemical tracers. This AIS tracers source will be activated with a boolean in the namelist_top named, for instance, ln_aistrc. 
     54Starting point to create the trc_ais routine (3 subroutines):  
     55- trc_sbc (trc_bc?) for the structure 
     56- trc_ice for initialization, calling/reading of the 24 bgc tracers 
     57- p4zsed for interpolation and read freshwater flux from icebergs and ice shelves 
     59To be added in the namelist_top 
     60- isffeinput: Fraction of bioavailable iron in ice shelves 
     61- icbfeinput: Fraction of bioavailable iron in iceberg 
     62- icbdepth: surface distribution (0) or throughout the water column until 120 m (1) 
     64Do we use the same value fraction of bioavailable iron for both sources? 
     66Warning: the isf source has to be activated in the namelist_cfg: parameter nn_isf >0  
     68Orginally (activated in namelist_pisces_cfg  with boolean ln_ironice) 
     70Modified routines: p4zsed, p4zsbc 
     72Intermediate variables created to compute ziron variable:  
     73- zironberg: iron from iceberg freshwater flux 
     74- zironisf: iron from ice shelves freshwater flux 
     77originally modified routines : 
    4178- p4zsbc.F90  
    4279- p4zsed.F90 
    4683- zironisf  : "iron from ice shelf freshwater flux" 
    48 In namelist_pisces, 3 parameters are added:\\ 
     85In namelist_pisces, 3 parameters were added:\\ 
    4986- isffeinput : "Fraction of bioavailable iron from ice shelves"\\ 
    5087- icbfeinput : "Fraction of bioavailable iron from icebergs"\\