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last modified Dec 02, 2015 01:07 PM
ScalES
Provide generic software libraries for recurring topics in climate model implementation.

Name: ScalES
Contact: Thomas Jahns
Start: Jan 01, 2009
End: Dec 31, 2011
Lead: DKRZ (Germany)
Participants: 5 partners from Germany
Funded by: BMBF
Homepage: www.dkrz.de
Component models used
JSBACH: representing the land surface
HAMOCC: representing the ocean biogeochemistry
MPIOM: representing the ocean and sea ice
ECHAM6: representing the atmosphere
Earthsystem models used
COSMOS
Earth system modelling tools used
OASIS4
MESSy for ECHAM5

Project Description

Models for climate and earth-system simulation (earth system model, ESM) do currently show a multitude of code structures that were very efficiently computed on architectures of the past, where only few very powerful CPU cores delivered results.

Such models are now and increasingly will be coupled in complex multi-model simulations to be run on parallel HPC systems with 1000 up to millions of cores. Unfortunately many models do not yet run efficiently at such a scale.

An example for such models are those used for the last IPCC report. Since these models are needed in the creation of climate scenarios and climate predictions, which in turn form the basis for decisions in many contexts of our society. One example for the dissemination of those results is the Climate Service Center established by the German federal ministry of education and research.

To meet these targets, improvements of future model generations with respect to accuracy and complexity are indispensable. These improvements are heavily reliant on efficently scaling the models to high CPU counts.

The ScalES project was conceived as a means to identify and solve scaling problems common to many model codes in an examplary fashion for a coupled ESM. A central commitment of the project is the establishment of a prototypical, flexible and highly scalable ESM of production quality. A special focus will further be the conception and implementation of generic library components that will be useful as well for other ESM as completely different disciplines of research.

Software Components

Parallel I/O library and I/O servers

Data transport and storage in todays earth system models is increasingly time consuming due to its essentially serial implementation and continually increasing parallelization and resolution. To fully exploit state-of-the-art parallel filesystems like GPFS or Lustre, the model I/O needs to be restructured and parallelized.

This projects aims to develop such an implementation and make it available in a library covering multiple libraries.

Parallelization and Performance modules

To mitigate both dynamic and static load imbalance a collection of partitioning routines will be implemented beneath a common interface. Additionally helper routines for associated phenomena in parallelized programs will complement this core with e.g. free-form boundary exchanges.

The library can be inspected at the dkrz project server: scales-ppm

Improvements of OASIS 4 coupler

One of the core features of modern ESM is the coupler, which handles the communication between the individual climate components. It has to be easy to use, allow the easy exchange of models and run performant on different computer architetures. The coupler OASIS4, which is used in this project, is one of the standard tools in the climate research community.

Solver for ocean level with machine targetted parametrization

Improvement of the current solver by implementing the cg method and additive Schwarz method. Usage of hybrid parallelization to exploit different hardware architectures more efficiently. The solver is included in scales-ppm.

Funding/Förderung

Förderkennzeichen: 01IH08004E

 

Most of these information have been collected from ScalES´s homepage .They have been last updated on Dec 02, 2015
Filed under: Project, National