******************** eORCA025.L121-OPM021 ******************** Summary ======= Compare to eORCA025.L121-OPM020, we change the icb distribution (stern et al. 2016) and some sea ice parameters (drag and snow conductivity) based on Katherine simulation. Namelist ======== Only the change compare to the reference (eORCA025.L121-OPM020) a mentioned in the next sections. Full files are available here: https://github.com/pmathiot/NEMOCFG/tree/main/cfgs/eORCA025.L121-OPM021/cfgs/eORCA025.L121-OPM021/EXPREF namelist_ice ------------ namdyn_rhg ~~~~~~~~~~ * the simulation do not use the aevp rheology, and only iterate 100 times instead of 120 times. .. code-block:: console !------------------------------------------------------------------------------ &namdyn_rhg ! Ice rheology !------------------------------------------------------------------------------ ln_rhg_EVP = .true. ! EVP rheology ln_aEVP = .false. ! adaptive rheology (Kimmritz et al. 2016 & 2017) rn_creepl = 2.0e-9 ! creep limit [1/s] rn_ecc = 2.0 ! eccentricity of the elliptical yield curve nn_nevp = 120 ! number of EVP subcycles rn_relast = 0.333 ! ratio of elastic timescale to ice time step: Telast = dt_ice * rn_relast ! advised value: 1/3 (nn_nevp=100) or 1/9 (nn_nevp=300) nn_rhg_chkcvg = 0 ! check convergence of rheology ! = 0 no check ! = 1 check at the main time step (output xml: uice_cvg) ! = 2 check at both main and rheology time steps (additional output: ice_cvg.nc) ! this option 2 asks a lot of communications between cpu / namsbc ~~~~~~ * the ice-ocean drag is set to 5e-3 instead of 12e-3 .. code-block:: console !------------------------------------------------------------------------------ &namsbc ! Ice surface boundary conditions !------------------------------------------------------------------------------ rn_cio = 5.0e-03 ! ice-ocean drag coefficient (-) nn_snwfra = 2 ! calculate the fraction of ice covered by snow (for zdf and albedo) ! = 0 fraction = 1 (if snow) or 0 (if no snow) ! = 1 fraction = 1-exp(-0.2*rhos*hsnw) [MetO formulation] ! = 2 fraction = hsnw / (hsnw+0.02) [CICE formulation] rn_snwblow = 0.66 ! mesure of snow blowing into the leads ! = 1 => no snow blowing, < 1 => some snow blowing nn_flxdist = -1 ! Redistribute heat flux over ice categories ! =-1 Do nothing (needs N(cat) fluxes) ! = 0 Average N(cat) fluxes then apply the average over the N(cat) ice ! = 1 Average N(cat) fluxes then redistribute over the N(cat) ice using T-ice and albedo sensitivity ! = 2 Redistribute a single flux over categories ln_cndflx = .false. ! Use conduction flux as surface boundary conditions (i.e. for Jules coupling) ln_cndemulate = .false. ! emulate conduction flux (if not provided in the inputs) nn_qtrice = 1 ! Solar flux transmitted thru the surface scattering layer: ! = 0 Grenfell and Maykut 1977 (depends on cloudiness and is 0 when there is snow) ! = 1 Lebrun 2019 (equals 0.3 anytime with different melting/dry snw conductivities) / namthd_zdf ~~~~~~~~~~ * the snow conductivity is increased from 0.31 to 0.35 .. code-block:: console !------------------------------------------------------------------------------ &namthd_zdf ! Ice heat diffusion !------------------------------------------------------------------------------ ln_zdf_BL99 = .true. ! Heat diffusion follows Bitz and Lipscomb 1999 ln_cndi_U64 = .false. ! sea ice thermal conductivity: k = k0 + beta.S/T (Untersteiner, 1964) ln_cndi_P07 = .true. ! sea ice thermal conductivity: k = k0 + beta1.S/T - beta2.T (Pringle et al., 2007) rn_cnd_s = 0.35 ! thermal conductivity of the snow (0.31 W/m/K, Maykut and Untersteiner, 1971) ! Obs: 0.1-0.5 (Lecomte et al, JAMES 2013) rn_kappa_i = 1.0 ! radiation attenuation coefficient in sea ice [1/m] rn_kappa_s = 10.0 ! nn_qtrice = 0: radiation attenuation coefficient in snow [1/m] rn_kappa_smlt = 7.0 ! nn_qtrice = 1: radiation attenuation coefficient in melting snow [1/m] rn_kappa_sdry = 10.0 ! radiation attenuation coefficient in dry snow [1/m] ln_zdf_chkcvg = .false. ! check convergence of heat diffusion scheme (outputs: tice_cvgerr, tice_cvgstp) / namthd_do ~~~~~~~~~ * the frazil ice parametrization is turned off .. code-block:: console !------------------------------------------------------------------------------ &namthd_do ! Ice growth in open water !------------------------------------------------------------------------------ rn_hinew = 0.1 ! thickness for new ice formation in open water (m), must be larger than rn_himin ln_frazil = .false. ! Frazil ice parameterization (ice collection as a function of wind) rn_maxfraz = 1.0 ! maximum fraction of frazil ice collecting at the ice base rn_vfraz = 0.417 ! thresold drift speed for frazil ice collecting at the ice bottom (m/s) rn_Cfraz = 5.0 ! squeezing coefficient for frazil ice collecting at the ice bottom / Monitoring ========== .. _eORCA025.L121-OPM021_monitoring: Global indicators ----------------- On these plot you can find a time series of: - ACC transport - AMOC at rapid array - AMHT at rapid array - Net global heat fluxes - mean sst in the southern ocean (see box in the map) - mean sst in the North West Corner (see box in the map) - sea ice extent (arctic/ant in summer/winter) .. image:: _static/VALGLO_OPM021.png Regional indicators ------------------- On these plot, you can find time series of: - ACC transport - Maximum of the Weddell and Ross Gyre (box where the max compute show in the map) - Mean bottom salinity over the main dense water formation hot spot (West Ross and West FRIS) - Mean bottom temperature over East Ross and Amudsen sea to monitor CDW intrusion .. image:: _static/VALSO_OPM021.png Local indicators ---------------- These plots monitor the evolution of ice shelf melting and the corresponding shelf properties (ROSS, FRIS, PINE, GETZ) .. image:: _static/VALSI_OPM021.png Amundsen/Belingshausen seas --------------------------- These plot monitoring the evolution of temperature, salinity and ice shelf melt in Amundsen sea. .. image:: _static/VALAMU_OPM021.png Ice shelves ----------- Amery ~~~~~ .. image:: _static/AMER_eORCA025.L121-OPM021.png Ross ~~~~ .. image:: _static/ROSS_eORCA025.L121-OPM021.png Getz ~~~~ .. image:: _static/GETZ_eORCA025.L121-OPM021.png Pine island ~~~~~~~~~~~ .. image:: _static/PINE_eORCA025.L121-OPM021.png George VI ~~~~~~~~~ .. image:: _static/GEVI_eORCA025.L121-OPM021.png Filschner Ronne ~~~~~~~~~~~~~~~ .. image:: _static/FRIS_eORCA025.L121-OPM021.png Riiser ~~~~~~ .. image:: _static/RIIS_eORCA025.L121-OPM021.png Fimbul ~~~~~~ .. image:: _static/FIMB_eORCA025.L121-OPM021.png Evaluation ========== Ice shelf melt: the pictures below are the climatological melt for all the ice shelves in NEMO for the OPM020 and OPM021 simulations over the last decade of the simulations (2029-2038) by sectors. .. image:: _static/WAIS_eORCA025.L121-OPM021_OPM020_y2029_10y.png :scale: 27% .. image:: _static/EAIS_eORCA025.L121-OPM021_OPM020_y2029_10y.png :scale: 27% .. image:: _static/WEDD_eORCA025.L121-OPM021_OPM020_y2029_10y.png :scale: 27% Map of ice shelf melt for both simulations OPM020 and OPM021 over the last decade of the simulations (2029-2038) with bottom temperature. .. image:: _static/melt_sector_OPM020_2029-2038.png :scale: 20% .. image:: _static/melt_sector_OPM021_2029-2038.png :scale: 20% Map of barotropic stream function for both simulations OPM020 and OPM021 over the last decade of the simulations (2029-2038) .. image:: _static/BSF_y2029_OPM020_OPM021.png