5 Glossary

component

A component is the software instantiation of a climate system model component such as the atmosphere, ocean, sea ice, or land surface.

package

A package is an independently testable coding unit. The package concept corresponds closely with a class. Packages are composed of modules.

module

Modules correspond to Fortran 90 modules. Modules are composed of data objects and procedures that act on these objects.

derived data type

A derived data type is a user defined definition of logical construct to be used as an abstraction in the software. Derived types are supported in Fortran 90.

package interface

A package interface is the specification of use for a package. It includes the procedures for initializing and calling the package as well as the description for the log, history and restart mechanisms within the package.

patch

A patch is an arbitrary possibly non-contiguous land surface area.

grid cell

A grid cell is a single point at the coarsest resolution of the land model. Land grid cells correspond to atmosphere grid cells.

land unit

A land unit is a sub-grid cell patch representing particular surface properties. Land units come in two flavors: "special" types (which include urban and lake patches) and "regular" types (which include all real vegetation type patches).

column

A column is a sub-land unit patch representing particular plant functional types. Each "regular" land unit contains one or more columns corresponding to the number of plant functional types within the land unit. "Special" land units consist of a single column.

plant functional type

A plant functional type is particular vegetation class or category describing a column within a land unit contained in a grid cell.