ice_amount_accounting_error = tendency_of_ice_amount -
  (tendency_of_ice_amount_due_to_flow +
   tendency_of_ice_amount_due_to_conservation_error +
   tendency_of_ice_amount_due_to_surface_mass_flux +
   tendency_of_ice_amount_due_to_basal_mass_flux +
   tendency_of_ice_amount_due_to_discharge);

ice_amount_accounting_error@long_name = "ice amount accounting error";