Using CIME Basic

Basic CIME

To add to this section:
1. setting CIME enabled model system via the environment variable CIME_MODEL
2. what is a model compset? - definition of long compset name
   what is a model resolution? - definition of long grid name
   using manage case to determine possible resolutions, machines
3. basic create_newcase use (including , etc)
4. $CASEROOT -
   what a user can do inside $CASEROOT to change characteristics of runs or make new runs.
   how to change the pe layout
   All the tools inside $CASEROOT.
5. create_clone (?)

Introduction

This guide instruct novice users on building and running an Earth System Model with CIME. If you are a new user, we recommend that the introductory sections be read before moving onto other sections or the Quick Start procedure. This document is written so that, as much as possible, individual sections stand on their own and the user's guide can be scanned and sections read in a relatively ad hoc order.

Prerequisites

CIME runs on UNIX-like operating systems. CIME requires some software be available on the system:

• python 2.7+
• perl 5.10+
• netcdf 4.3.3.1+ (both Fortran and C interfaces)
• c and fortran compilers
• MPI library
• gnu make
• cmake

Before you can run any cime script the CIME_MODEL needs to be set. It can be in an environment variable or it can be set in the users ~/.cime/config file. The variable PROJECT is also required on many HPC systems. Here is an example of a basic .cime/config file defining CIME_MODEL and PROJECT:

[main]
CIME_MODEL=cesm
PROJECT=Pxxxx

Creating and Setting up a Case

CIME supports out of the box component sets, model grids and hardware platforms. Component sets (usually referred to as compsets) define both the specific model components that will be used in a given CIME configuration, and any component-specific namelist or configuration settings that are specific to this configuration. Both compsets and models grids are now associated with three names: a new longname, a short name and an alias name.

There are 4 basic steps that are executed by the user on the command line to configure, build and run a case with CIME:

1. create_newcase
2. case.setup
3. case.build
4. case.submit

create_newcase

create_newcase supports many arguments but the required ones are --case, --compset and --res.

Following is a simple example of using create_newcase: In what follows, $CIMEROOT is the full pathname of the root directory of CIME which will typically be one level below the root of the CIME-enabled model.

> cd $CIMEROOT/scripts
> create_newcase --case ~/example1 --compset B_1850 --res ne30np4_gx1v6

Explanation of arguments:

case

The location of what will be the $CASEROOT which is where all your work to configure and build cases will occur.

compset

The component set of you wish to run. Allowable options will depend on the model using CIME.

res

The resolutions of the components in the compset. Allowable options will depend on the model using CIME