From 4321db104df5bf4467b77cde3e14f1bb5116a1da Mon Sep 17 00:00:00 2001 From: JFLemieux73 Date: Tue, 9 Mar 2021 20:59:25 +0000 Subject: [PATCH 1/2] Modified k1 value and some of the doc --- cicecore/cicedynB/general/ice_init.F90 | 2 +- configuration/scripts/ice_in | 2 +- doc/source/science_guide/sg_dynamics.rst | 21 ++++++++++----------- 3 files changed, 12 insertions(+), 13 deletions(-) diff --git a/cicecore/cicedynB/general/ice_init.F90 b/cicecore/cicedynB/general/ice_init.F90 index 91c0d10b1..b59a93862 100644 --- a/cicecore/cicedynB/general/ice_init.F90 +++ b/cicecore/cicedynB/general/ice_init.F90 @@ -331,7 +331,7 @@ subroutine input_data close_boundaries = .false. ! true = set land on edges of grid seabed_stress= .false. ! if true, seabed stress for landfast is on seabed_stress_method = 'LKD' ! LKD = Lemieux et al 2015, probabilistic = Dupont et al. in prep - k1 = 8.0_dbl_kind ! 1st free parameter for landfast parameterization + k1 = 7.5_dbl_kind ! 1st free parameter for landfast parameterization k2 = 15.0_dbl_kind ! 2nd free parameter (N/m^3) for landfast parametrization alphab = 20.0_dbl_kind ! alphab=Cb factor in Lemieux et al 2015 threshold_hw = 30.0_dbl_kind ! max water depth for grounding diff --git a/configuration/scripts/ice_in b/configuration/scripts/ice_in index b1fa561a8..f34db14f0 100644 --- a/configuration/scripts/ice_in +++ b/configuration/scripts/ice_in @@ -131,7 +131,7 @@ e_ratio = 2. seabed_stress = .false. seabed_stress_method = 'LKD' - k1 = 8. + k1 = 7.5 k2 = 15. alphab = 20. threshold_hw = 30. diff --git a/doc/source/science_guide/sg_dynamics.rst b/doc/source/science_guide/sg_dynamics.rst index 5d720ed9b..7c1d43cb2 100644 --- a/doc/source/science_guide/sg_dynamics.rst +++ b/doc/source/science_guide/sg_dynamics.rst @@ -240,9 +240,7 @@ CICE includes two options for calculating the seabed stress, i.e. the term in the momentum equation that represents the interaction between grounded ice keels and the seabed. The seabed stress can be activated by setting ``seabed_stress`` to true in the namelist. The seabed stress (or basal -stress) parameterization of :cite:`Lemieux16` is chosen if ``seabed_stress_method`` -= ``LKD`` while the new probabilistic approach is used if ``seabed_stress_method`` -= ``probabilistic``. +stress) parameterization of :cite:`Lemieux16` is chosen if ``seabed_stress_method`` = ``LKD`` while the approach based on the probability of contact between the ice and he seabed is used if ``seabed_stress_method`` = ``probabilistic``. For both parameterizations, the components of the seabed stress are expressed as :math:`\tau_{bx}=C_bu` and @@ -301,7 +299,7 @@ keels in the Arctic Ocean :cite:`Amundrud04`. Seabed stress based on probabilistic approach ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -This new and more sophisticated grounding parameterization computes the seabed stress based +This more sophisticated grounding parameterization computes the seabed stress based on the probability of contact between the ice thickness distribution (ITD) and the seabed. Multi-thickness category models such as CICE typically use a few thickness categories (5-10). This crude representation of the ITD @@ -335,8 +333,7 @@ ITD and the seabed is given by y)g(x)b(y) dy dx, \\ :label: Tbt -and then obtains :math:`T_{bt}` by multiplying :math:`T_{bt}^*` by :math:`e^{-\alpha_b * (1 - a_i)}` (similar to what is done for -``kseabed`` = 1). +and then obtains :math:`T_{bt}` by multiplying :math:`T_{bt}^*` by :math:`e^{-\alpha_b * (1 - a_i)}` (similar to what is done for ``seabed_stress_method`` = ``LKD``). To calculate :math:`T_{bt}^*` in equation :eq:`Tbt`, :math:`f(x)` and :math:`b(y)` are discretized using many small categories (100). :math:`f(x)` is discretized between 0 and 50 m while :math:`b(y)` is truncated at plus and minus three :math:`\sigma_b`. :math:`f(x)` is also modified by setting it to zero after a certain percentile of the log-normal distribution. This percentile, which is currently set to 99.7%, notably affects the simulation of landfast ice and is used as a tuning parameter. Its impact is similar to the one of the parameter :math:`k_1` for the LKD method. @@ -346,7 +343,7 @@ To calculate :math:`T_{bt}^*` in equation :eq:`Tbt`, :math:`f(x)` and :math:`b(y T_b=\max[T_{bt}(i,j),T_{bt}(i+1,j),T_{bt}(i,j+1),T_{bt}(i+1,j+1)]. \\ :label: Tb -Following again the approach of ``kseabed`` = 1, the seabed stress coefficients are finally expressed as +Following again the LKD method, the seabed stress coefficients are finally expressed as .. math:: C_b= T_b (\sqrt{u^2+v^2}+u_0)^{-1}, \\ @@ -385,7 +382,11 @@ is therefore simply equal to :math:`-\sigma_1/2`. Following the approach of :cite:`Konig10` (see also :cite:`Lemieux16`), the elliptical yield curve can be modified such that the ice has isotropic tensile strength. The tensile strength :math:`T_p` is expressed as a fraction of the ice strength :math:`P`, that is :math:`T_p=k_t P` -where :math:`k_t` should be set to a value between 0 and 1 (this can be changed at runtime with the namelist parameter ``Ktens``). +where :math:`k_t` should be set to a value between 0 and 1 (this can +be changed at runtime with the namelist parameter ``Ktens``). The ice +strength :math:`P` is a function of the ice thickness distribution as +described in the `Icepack +Documentation`_. .. _stress-vp: @@ -416,9 +417,7 @@ and :math:`P_R` is a “replacement pressure” (see :cite:`Geiger98`, for example), which serves to prevent residual ice motion due to spatial variations of :math:`P` when the rates of strain are exactly zero. -The ice strength :math:`P` -is a function of the ice thickness and concentration -as described in the `Icepack Documentation `_. The parameter :math:`e` is the ratio of the major and minor axes of the elliptical yield curve, also called the ellipse aspect ratio. It can be changed using the namelist parameter ``e_ratio``. +The parameter :math:`e` is the ratio of the major and minor axes of the elliptical yield curve, also called the ellipse aspect ratio. It can be changed using the namelist parameter ``e_ratio``. .. _stress-evp: From d5c62279df935e70df6e3a1da2093b390df5742d Mon Sep 17 00:00:00 2001 From: JFLemieux73 <31927797+JFLemieux73@users.noreply.github.com> Date: Thu, 11 Mar 2021 11:00:45 -0500 Subject: [PATCH 2/2] Update doc/source/science_guide/sg_dynamics.rst Co-authored-by: Philippe Blain --- doc/source/science_guide/sg_dynamics.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/doc/source/science_guide/sg_dynamics.rst b/doc/source/science_guide/sg_dynamics.rst index 7c1d43cb2..ecef531b4 100644 --- a/doc/source/science_guide/sg_dynamics.rst +++ b/doc/source/science_guide/sg_dynamics.rst @@ -240,7 +240,7 @@ CICE includes two options for calculating the seabed stress, i.e. the term in the momentum equation that represents the interaction between grounded ice keels and the seabed. The seabed stress can be activated by setting ``seabed_stress`` to true in the namelist. The seabed stress (or basal -stress) parameterization of :cite:`Lemieux16` is chosen if ``seabed_stress_method`` = ``LKD`` while the approach based on the probability of contact between the ice and he seabed is used if ``seabed_stress_method`` = ``probabilistic``. +stress) parameterization of :cite:`Lemieux16` is chosen if ``seabed_stress_method`` = ``LKD`` while the approach based on the probability of contact between the ice and the seabed is used if ``seabed_stress_method`` = ``probabilistic``. For both parameterizations, the components of the seabed stress are expressed as :math:`\tau_{bx}=C_bu` and