doc/phys_pkgs/darwin_airsea.rst

3c930300af Oliv*0001 .. include:: ../defs.hrst
                0002
                0003 .. _AirSea:
                0004
                0005 Air-sea exchanges
                0006 ^^^^^^^^^^^^^^^^^
                0007
                0008 The preprocessor option :varlink:`DARWIN_ALLOW_CARBON` is required to enable
                0009 the computation of air-sea exchanges and the oxygen tracer.
                0010
                0011 The surface flux of DIC is
                0012
                0013 .. math::
                0014
                0015    \mathcal{F}_{\mathrm{DIC}} = \rho_o K_{\text{g}}^{\mathrm{CO2}}
                0016       \bigl(
                0017       [\op{CO}_2^{\text{at}}] - [\op{CO}_2^*]
                0018       \bigr)
                0019
                0020 with
                0021
                0022 .. math::
                0023
                0024    K_{\text{g}}^{\mathrm{CO2}} = \frac{0.337\op{cm}\op{h}^{-1}}{\op{m}^2/\op{s}^2} w^2
                0025    \left(\frac{\op{Sc}_{\mathrm{CO2}}}{660}\right)^{-1/2}
                0026    (1-f_{\text{ice}})
                0027
                0028 .. math::
                0029
                0030    [\op{CO}_2^*] = [\op{CO}_2] + [\mathrm{H_2CO_3}]
                0031
                0032 .. math::
                0033
                0034    [\op{CO}_2^{\text{at}}] = F p_{\op{CO}_2}^{\text{at}}
                0035
                0036 .. math::
                0037
                0038    p_{\op{CO}_2}^{\text{at}} = p^{\text{at}} \cdot x_{\op{CO}_2}^{\text{at}}
                0039
                0040 where :math:`w` is the wind speed and :math:`f_{\text{ice}}` is the surface
                0041 fraction covered by ice, read in from :varlink:`icefile` or taken from the
                0042 seaice package if :varlink:`useSEAICE` is set to true.  The Schmidt number for
                0043 CO\ :sub:`2`, Sc\ :sub:`CO2`, is parameterized according to Wanninkhof (1992)
                0044 :cite:`wannink:92`, with values below 0.01 cut.  :math:`F` is computed
                0045 following Weiss and Price (1980) :cite:`weiss:80`.  The reference density of
                0046 seawater, :math:`\rho_o`, is set via its inverse, :varlink:`m3perkg`.  The
                0047 units of CO\ :sub:`2` concentrations here are mol/kg.
                0048 :math:`[\mathrm{CO}_2^*]` is computed in :ref:`CarbonChemistry`.
                0049
                0050 The surface flux of oxygen is
                0051
                0052 .. math::
                0053
                0054    \mathcal{F}_{\mathrm{O2}} = K_{\text{g}}^{\mathrm{O2}} \bigl(
                0055       [\op{O}_2^{\text{sat}}] - [\op{O}_2]
                0056       \bigr)
                0057
                0058 with
                0059
                0060 .. math::
                0061
                0062    K_{\text{g}}^{\mathrm{O2}} = \frac{0.337\op{cm}\op{h}^{-1}}{\op{m}^2/\op{s}^2} w^2
                0063    \left(\frac{\op{Sc}_{\mathrm{O2}}}{660}\right)^{-1/2}
                0064    (1-f_{\text{ice}})
                0065
                0066 .. math::
                0067
                0068    [\op{O}_2^{\text{sat}}] = p^{\text{at}} C_o^*
                0069
                0070 The saturated concentration of O\ :sub:`2` at 1 atm, :math:`C_o^*`, is computed
                0071 following Garcia and Gordon (1992) :cite:`garcia:92`.  The Schmidt number of
                0072 oxygen according to Keeling et al. (1998) :cite:`keeling:98`.  The units of
                0073 oxygen concentrations are mmol m\ :sup:`-3`.
                0074
                0075
                0076 .. csv-table:: Air-sea exchange parameters
                0077    :delim: &
                0078    :widths: auto
                0079    :header: Name, Symbol, Default, Units, Description
                0080    :name: phys_pkg_darwin_airsea_parameters
                0081
                0082    :varlink:`m3perkg`  & :math:`1/\rho_o` & 1 / 1024.5            & m\ :sup:`3`/kg                   & constant for converting per kg to per m\ :sup:`3`
                0083    :varlink:`darwin_useSEAICE` & & .FALSE. & & whether to use ice area from the seaice package