ALMA Standard Model Output

A summary of standard output variable definitions for land surface scheme intercomparisons is given below. It is expected that this list will grow over time as the requirement of the various GLASS projects becomes known.

As indicated in the table, one of two sign conventions may be adopted at the discretion of the participant. All output variables must conform to one of these two conventions. The choice must be included in the netCDF header information of the output file.

The time sampling of each of the variables will be specified by each inter-comparison project. This is an issue which depends on the data available for validation and the scientific objectives of the project. As a general rule fluxes are averaged over the time-step. Other variables on the contrary should be instantaneous samples in order to capture well the diurnal cycleor total change. This obviously only applies if the time sampling is high enough for the instantaneous variables to be representative of the time interval. For this table, variables which must be returned as averages are in red.

The variables have been grouped into seven general categories which go from very general to highly specialized :

O.1) General energy balance components

This table should provide the main energy fluxes at the surface so that a verification of the long term energy balance can be made.

O.2) General water balance components

In this table all grid-averaged components of the water balance are requested. These components should enable an analysis of the water balance of the model.

O.3) Surface state variables

This table provides the basic state variables at the surface which are simulated by the schemes.It documents in a general way the simulated evolution of the surface.

O.4) Sub-surface state variables

In this table the state of the subsurface is described. Its thermodynamics as well as its hydrological conditions are described without going into the details of the various processes.

O.5) Evaporation components

This table details the evaporation fluxes and thus describes all the components which make up the water flux from the surface to the atmosphere.

O.6) Streamflow

This specialized table documents the lateral flow of water in the land-surface scheme if it is simulated.

O.7) Cold season processes

This specialized table will document in as much details as possible the simulated cold season processes.

(Expected range)