The main loop is contained wholly within the MAIN routine. The order of calling to the physics routines is quite tightly controlled and cannot be changed arbitrarily. Some calls are dummy calls depending on how the model is coupled and which 'plug-and-play' options are in effect. Currently the calling order is: DYNAM (atmospheric dynamics), MELTSI (sea ice lateral melt), CONDSE (moist convection and large scale condensation), RADIA (radiative transfer), PRECIP_XYZ application of precipitation to submodules, SURFCE (calculation of surface heat, water and momentum fluxes), DYNSI (calculation of advective tendencies in sea ice), UNDERICE (calculation of ice-ocean heat, mass and salt fluxes), GROUND_XYZ application of surface fluxes to land surface submodules (earth, land ice, lakes), RIVERF (calculation of river routing), OCEANS (application of surface fluxes and rivers to ocean code), FORM_SI (update of ice module to account for any ice formation in lakes or oceans), ADVSI (advection of sea ice), DISSIP (add heat from atmospheric dissipation to atmosphere), FILTER (pressure filter). At the end of the day calls are made to various daily_XYZ routines that calculate changes (such as in climatologies) that only need be done daily.