Community Ice Sheet Model
The Community Ice Sheet Model is being developed at Los Alamos National Laboratories, University of Montana, Missoula and elsewhere. The effort began from the Glimmer ice sheet model developed in Bristol by Tony Payne, Ian Rutt, and Magnus Hagdorn.
The core improvements that CISM provides are:
ISIS is an acronym for Interactive System for Ice sheet Simulation. Isis also happens to be the Egyptian goddess of fertility. This is an appropriate name in that our objective is to produce more modelers. ISIS attempts to spawn more modelers by lowering the barrier to trying ice sheet modeling by
- Providing a compiled version of an ice sheet model on Mac, Linux, and Windows platforms.
- Provide interesting data sets and scenarios that can be run with the model.
- Provide some simple tools for visualizing the model results.
Versions of ISIS have been prepared for Linux, OS X, and Windows operating systems. Download them here.
The Computer Science Department at East Tennessee State University has made several changes to ISIS. ETSU ISIS provides a
- command line option for enabling educational mode,
- a generic model class (PISM and Glimmer included), and
- various bug fixes
For more information on ETSU ISIS see Software/ETSUISIS/Model
ETSU ISIS has been tested on Windows and OS X
Downloads will be available here soon
There is potential for Earth systems models to provide instruction for students in a range of subjects and at a range of levels. Seeking to target high school students, eduISIS was developed as an extension of ISIS with a simplified user interface.
Ice Sheet Models
The Parallel Ice Sheet Model being developed at the University of Alaska, Fairbanks has provided CISM with many fresh ideas for model verification and data interchange. Ultimately, it will be desirable to have a common interface to both models, allowing for rapid cross model comparisons. For the time being, the first step is a common data format. This is largely completed, but remains to be tested in more depth.
CISM efforts began from the Glimmer ice sheet model developed in Bristol by Tony Payne, Ian Rutt, and Magnus Hagdorn. This is a thermo-mechanically coupled shallow ice model that uses an implicit finite difference scheme to solve the field equations. Beyond this level of simulation, Glimmer has a number of attractive software features including;
- NetCDF support,
- Automake build system,
- modular architecture created in FORTRAN 90,
- Open Source, GPL license,
- designed with interface to climate models in mind, and
- set of test suites
Glimmer Netcdf Data Conversion Program
Data used by Glimmer is initially stored in separate data files with a ".dat" file extension. The advantage to the data conversion is to eliminate having multiple files by merging them into one Netcdf file. The data converting program is a Java application that allows users to open data files and convert them to Netcdf format. The conversion program examines each data file and reads the format instruction at the beginning of each file. This information is read based on a parse tree that is created using a data file with the rules for the instruction's grammar. The file's data is then read and stored in a multi-dimensional ArrayList. This multi-dimensional ArrayList is then written to a Netcdf file.
Glimmer Netcdf Data Portability Analysis
ESML stands for Earth Science Markup Language. "ESML is an interchange technology that enables data (both structural and semantic) interoperability with applications without enforcing a standard format within the Earth Science community". ESML is basically a metadata file written in the XML grammar syntax which describes the contents of another data file. ESML metadata file can be used by different data readers with the help of ESML library. This way data readers can read any data format that has an ESML file associated with it. ESML library is currently supported in C++. An ESML file for the glimmer netcdf data can be created making the glimmer data more portable.
ncML is an XML based language for netCDF data files. It is also a metadata language which explains the contents of an associated netCDF file.
ncML-GML is a hybrid technology of ncML and GML. ncML-GML uses both ncML and GML grammer. Study of this technology is in progress and more information will be updated very soon.