Speaker
Dr
Joachim Biercamp
(DKRZ)
Description
Human made climate change and its impact on the natural and socio-economic
environment is one of todays most challenging problems of mankind. To understand and
project processes, changes and impacts of the natural and socio-economic system a
growing community of researchers from various disciplines investigates and analyses
the earthsystem by means of computer simulation and analysis models.
These models are usually computational demanding and data intensive as they need to
compute and store high resolved 4-dimensional fields of various parameters. Moreover,
the required close collaboration in interdisciplinary and often also international
research projects involves intensive community interactions.
To support climate workflows the community established proprietary, mostly national
or regional solutions, which are normally grouped around centralized high performance
computing and storage resources. Homogeneous discovery of and access to climate data
sets residing in distributed petabyte climate archives as well as distributed
processing and efficient exchange of climate data are the central components of
future international climate research. Thus, the EGEE infrastructure potentially
offers a highly suitable environment for such applications.
However, existing grid infrastructures - including EGEE - do not yet meet the
requirements of the climate community essential for prevalent workflows. Hence, to
port existing applications and workflows on the EGEE infrastructure, a stepwise
extension of the infrastructure to community specific services is needed. Moreover,
the identification and demonstration of feasibility and added value is essential to
convince the community to change their established habits. The Collaborative Climate
Community Data and Processsing Grid (C3-Grid [1]) is an application driven approach
towards the deployment of GRID techniques for climate data analysis. Solutions
currently developed in this project offer a potentially fruitful basis to improve the
suitability of the EGEE infrastructure as a platform for data analysis within climate
research.
Within EGEE climate is part of the Earth Science Research (ESR) VO. We evaluated and
tested the use of the EGEE infrastructure for climate applications [4]. As part of
this prototypes of simulation as well as analysis software were tested on the EGEE
infrastructure. We identified 3 different accesspoints for pilot applications, that
can demonstrate the potential benefit of the EGEE infrastructure for climate
research: Ensemble simulations with models of intermediate complexity, coupling
experiments on a common platform and data sharing and analysis.
Ensembles of simulations performed with the same model but different future scenarios
and different parameterisations are required to quantify the uncertainty and possible
variety of future climate predictions. EGEE offers a good infrastructure for such
ensemble simulations with models of intermediate complexity, which do not need the
performance of a supercomputer. Ensembles can be submitted as DAG, parametric or
collection job and results could be directly stored, analysed and reduced to the
required information on the grid.
The coupling of diverse models of different disciplines is essential to understand
the interaction and feedback between the different climate and earth system
components, as e.g. the human impact on future climate development. In corresponding
projects partners from different institutes of different nations are collaborating on
a common modeling framework. The EGEE infrastructure would be a valuable platform for
such coupling approaches. Data, models and output could be easily shared, different
access and user rights can be established via VOMS. Currently different coupling
tools are explored to assess their "grid-suitability".
Data sharing and analysis is a central aspect in climate research. The enormous
amounts of data, produced by the model simulations need to be analysed, visualised
and validated against observations or other data sources to be correctly interpreted.
This involves a multiplicity of statistical calculations carried out on samples of
different large data files. Currently such data analysis is centred around the
heterogeneous database systems, which are accessed via non-standardised metadata.
Thus, the establishment of a common data exchange and management infrastructure
bridging the existing heterogeneous community datamanagement solutions with the EGEE
data management system would add great value to such applications.
Especially for the realisation of climate data sharing and analysis workflows on EGEE
the following components need to be developed:
1) a common agreed upon metadata schema for discovery of climate data sets stored in
grid file space as well as in external community datacenters
2) a common community metadata catalogue based on this schema
3) common interfaces to reference and access grid external data resources (mainly
databases)
All of these aspects are addressed within the recently introduced national German
C3Grid [1] project within the German e-science (D-Grid [2]) initiative which aims to
develop a grid middleware specific for the needs of the climate research community.
Within this project a common metadata schema is defined. A community metadata
catalogue and information system is established and a common data access interface
will be defined.
To promote EGEE as a climate data handling (and postprocessing) infrastructure based
on these developments we propose a stepwise approach:
- establishment of an international standards based climate metadata catalog (e.g.
based on AMGA plus a common push/pull metadata exchange to grid external metadata
catalogues via established metadata harvesting protocols
- establishment of data access to (initially free) climate datasets in climate data
centers: As intial starting point we need an easy way to access data in climate data
centers and copy/register them on grid storage,
e.g. by using proprietary access clients or OGSA-DAI.
- adaptation of commonly used climate data processing toolkits on EGEE such as e.g.
cdo [3]
[1] http://www.c3grid.de
[2] http://www.d-grid.de
[3] http://www.mpimet.mpg.de/~cdo/
[4] Stephan Kindermann, EGEE infrastructure and Grids for Earth Sciences and Climate
Research, Technical report DKRZ (available under
http://c3grid.dkrz.de/moin.cgi/PublicDocs)
Author
Dr
Joachim Biercamp
(DKRZ)
Co-authors
Mrs
Kerstin Ronneberger
(DKRZ)
Dr
Stephan Kindermann
(DKRZ)
