In this section, salient features of the AMIP models are displayed in a series of tables, each of which illustrates how a selected feature, or group of similar features, plays out across the models. It should be noted that these tables tend to highlight inter-model differences; the broad similarities among the AMIP models are better conveyed by the more detailed Summary Reports, as are the many nuances of the models' features that cannot be expressed easily in tables.
Model representation/resolution. The table lists the horizontal representation and resolution; vertical coordinates and number of prognostic vertical levels (number below 800 hPa, above 200 hPa); and atmospheric bottom and top pressure levels, for a surface pressure of 1000 hPa
Computational information. The table lists the computer, number of processors, and operating system utilized; the computational performance (in minutes of computing time per simulated day); and the history storage interval.
Initialization. The table lists the data used (observational analyses, climatological datasets, or previous model solutions) for initialization of the atmosphere, soil moisture, and snow cover/depth.
Time integration. The table lists the numerical schemes and time-step lengths for integration of dynamics and full shortwave and longwave radiation calculations (with recalculation intervals of longwave absorptivities/emissivities, where different, noted in parentheses).
Filtering, smoothing, and filling. The table lists the instances of application of time filtering, spatial filtering/smoothing of model atmosphere and orography, or filling of spurious negative values of atmospheric moisture.
Diffusion and gravity-wave drag. The table lists the type of horizontal diffusion, if present; whether there is vertical diffusion of momentum, heat, or moisture above the planetary boundary layer (PBL); and references on the gravity-wave drag scheme, if present.
Atmospheric chemistry. The table lists the constituents (excluding uniformly mixed carbon dioxide at 345 ppm concentration and prognostic water vapor) that are included in the atmospheric radiation calculations. For prescribed ozone concentrations, data references are listed; for prognostic ozone, the parameterization schemes are referenced.
Atmospheric radiation. The table lists whether a diurnal cycle in solar forcing is simulated and the references for the principal shortwave and longwave atmospheric radiation schemes.
Cloud-radiative interactions. The table lists the treatment of shortwave and longwave cloud-radiative interactions, whether these depend on (prognostic, diagnostic, or prescribed) cloud liquid water (CLW), and the assumption of cloud vertical overlap used in the radiation calculations (random, full, or mixed--both random and full, depending on cloud type or other factors).
Convection. The table lists references on schemes used for simulation of deep and shallow convection, with brief descriptions.
Cloud formation and precipitation. The table lists the descriptions or references for the cloud-formation scheme, and whether this is based on prognostic cloud liquid water (CLW). For precipitation, the table lists instances of simulation of autoconversion processes, evaporation in falling, and stochastic spatial variation within a grid box at the surface.
Planetary boundary layer (PBL). The table shows whether the PBL depth is a prognostic variable and whether the surface fluxes of momentum, heat, and moisture are stability-dependent. References are also listed on the scheme to determine vertical diffusion from turbulence kinetic energy (TKE), if present.
Snow cover and sea ice. The table shows whether snow mass is a prognostic variable, and whether (prognostic or prescribed) snow cover alters the nonradiative thermal properties (heat capacity/conductivity, etc.) or roughness of the surface. For sea ice, the table shows whether the surface temperature is prognostically determined, and whether there is accumulation of snow on the ice.
Surface characteristics. The table shows whether the surface roughness (or, alternatively, the surface drag coefficient) is spatially variable over ocean, land, or sea ice. The table also shows whether the albedo of any surface depends on solar zenith angle or spectral interval, and whether there is graybody longwave emission (emissivity e < 1.0) from any surface.
Land surface processes. The table lists the number of soil layers for prognostic soil temperature and moisture (0 layers denotes no heat storage, or prescribed moisture); a description of (or references on) the prediction models; and references on the interactive vegetation model, if present.
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Last modified July 8, 1996. For further information, contact: Tom Phillips ( email@example.com )