bootstrap BTU_Full define_model_state_impl depth_impl init_impl m_bootstrapping_needed m_column m_D m_k m_Lbz m_Mbz m_temp max_timestep_impl Mz_impl temperature update_flux_through_top_surface update_impl update_impl vertical_spacing_impl write_model_state_impl ~BTU_Full

update_flux_through_top_surface() void pism::energy::BTU_Full::update_flux_through_top_surface ( ) protected Computes the heat flux from the bedrock thermal layer upward into the ice/bedrock interface: \[G_0 = -k_b \frac{\partial T_b}{\partial z}\big|_{z=0}.\] Uses the second-order finite difference expression \[\frac{\partial T_b}{\partial z}\big|_{z=0} \approx \frac{3 T_b(0) - 4 T_b(-\Delta z) + T_b(-2\Delta z)}{2 \Delta z}\] where \(\Delta z\) is the equal spacing in the bedrock. The above expression only makes sense when Mbz = temp.n_levels >= 3. When Mbz = 2 we use first-order differencing. When temp was not created, the Mbz <= 1 cases, we return the stored geothermal flux. Definition at line 210 of file BTU_Full.cc. References pism::array::Array2D< T >::copy_from(), m_bootstrapping_needed, pism::energy::BedThermalUnit::m_bottom_surface_flux, pism::Component::m_grid, m_k, m_Mbz, m_temp, pism::energy::BedThermalUnit::m_top_surface_flux, and pism::energy::BedThermalUnit::vertical_spacing(). Referenced by init_impl(), and update_impl().