Available standard setups

All standard setups are described in the section on Scientific documentation and references. The scientific documentation paper for Bedymo contains illustrations and discussion of different variants of these standard setups. For this reason, we here limit the documentation to a brief introduciton followed by a summary of some key aspects of the model configuration for each standard setup.

Cyclogenesis in a baroclinic channel

This setup is focused on the development of a primary cyclone from an initially small perturbation. The most rapid deepening of the cyclone happens after about 84 hours of lead time after which the primary cyclone has reached its mature stage. Downstream of the primary cyclone a series of secondary cyclone developments, the first of which reaching its mature stage around 120 hours of lead time. Eddy kinetic energy in QG cyclones tend to develop a little more rapidly than PE cyclones. PE cyclones tend to be smaller, deeper and associated with steeper surface pressure gradients.

Key aspects of the configuration

  • Mid-latitude channel with periodic boundaries in x-direction, walls in y-direction: latbdrtyp_ew = -1 and latbdrtyp_sn = 0.

  • Beta-plane with Coriolis parameters corresponding to 50N: fcor = 1.117e-4 and betacor = 1.472e-11.

  • Initialisation of a baroclinic zone with temperature perturbation init_type = 0.

  • Neither friction nor damping: lsurf_friction = F and ldamp = F.

  • The model is run up to a lead time of 10 days with output saved every 6 hours: tsstop = 864000 and dtout = 21600.

  • Horizontal resolution of 100 km, 3 levels in the vertical: dx = 100000., dy = 100000., and nz = 3.

Storm track in a baroclinic channel

This storm track setup is closely linked to the above cyclogenesis setup, but focusses on the mean storm track statistics rather than the initial development. Baroclinicity is restored through temperature relaxation and winds experience linear surface friction as well as scale-selective damping of the predominantly the smallest scales. After about 500 days of lead time the model achieves a statistically stationary state in which there no longer is a discernible trend in the sea-level pressure distribution within the model domain. We therefore recommend foscussing on lead times larger than 500 days for analyses of the storm track properties.

Key aspects of the configuration

Domain setup and initialisation as above, but including

  • Surface friction and damping: lsurf_friction = T and ldamp = T.

  • Temperature relaxation back towards the initial values: relax_coeff = 1.0e-6.

  • The model is run much longer with tsstop = 86400000, corresponding to 1000 days.

Planetary waves excited by isolated orography

An isolated idealised mountain triggers planetary waves in a mid-latitude beta-plane. The emerging stationary wave in the lee of the mountain closely follows the prediction from linear stationary wave theory.

Key aspects of the configuration

  • Again a mid-latitude channel with periodic boundaries in x-direction, walls in y-direction: latbdrtyp_ew = -1 and latbdrtyp_sn = 0.

  • Initialisation with horizontally homogeneous temperatures and homogeneous westerlies: init_type = 2.

  • Beta-plane with Coriolis parameters corresponding to 50N: fcor = 1.117e-4 and betacor = 1.472e-11.

  • An isolated Gaussian mountain with 1000 m height and meridional/zonal scales of 15 and 10 grid points, respectively: top_surftyp = 2, top_amp = 1000., top_ly = 15., and top_lx = 10..

Inertia-gravity waves excited by isolated orography (PE-only)

An isolated idealised mountain triggers inertia-gravity waves in a mid-latitude f-plane. The mountain is considerably smaller in horizontal extent than in the above planetary wave setup, and the model resolution is correspondinly higher. The emerging stationary wave pattern in the lee of the mountain closely follows the prediction from linear stationary wave theory. The QG system cannot represent inertia-gravity waves, such that this standard setup is available for PE only.

Key aspects of the configuration

  • TBD

Surface heating in an equatorial beta-plane (PE-only, coupled)

An isolated tropical SST anomaly centred on the equator heats the atmosphere in an equatorial beta-plane, and excites both a Rossby wave and an equatorial Kelvin-wave. The wave responses follow the expectations from the linear theories of Matsuno and Gill. The solution changes considerably once the atmosphere is set to induce Ekman transport in the ocean mixed layer (lcurrent_ekman = T). Further, the solution changes character fundamentally once the divergent wind-induced Ekman transport over the equator is set to upwell colder waters into the mixed layer (lreservoir_prescribed = T). The model domain contains the equator, such that this setup is only available for the PE model.

Key aspects of the configuration

  • The setup includes the slab-ocean locean_slab = T with a mixed-layer depth of 50 m: mixed_layer_depth = 50.

  • An equatorial channel with periodic boundaries in x-direction, walls in y-direction: latbdrtyp_ew = -1 and latbdrtyp_sn = 0.

  • Equatorial beta-plane: fcor = 0. and betacor = 1.472e-11.

  • Initialisation with horizontally homogeneous temperatures and homogeneous easterlies: init_type = 3.

  • By default, no wind-induced currents in the slab-ocean: lcurrent_ekman = F.