ESiWACE2 aims to improve model efficiency and prepare the software to enable model execution on existing and near-future hardware architectures and simulate experiments at unprecedented grid resolutions or ensemble sizes. In addition, it will include computationally expensive physical processes that were previously unfeasible.

The four new collaborations are:


Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany - Natalja Rakowsky
Finite-volumE Sea ice-Ocean Model, Version 2.0 (FESOM2)

FESOM2 is a global sea-ice ocean circulation model based on unstructured meshes. It allows to simulate the global ice-ocean system at extremely high resolution in the regions of interest at an affordable computational cost. The broad spectrum of FESOM2 applications includes several climate models and standalone sea ice-ocean configurations. The earth system components that have been successfully coupled to FESOM2 include:  ECHAM6.3, OpenIFS, REMO, PISM and ReCOM.

Two aspects will be addressed:

  1. Profile FESOM2 with GPUs in mind, and port the best suited numerical kernels to GPUs.
  2. Get a fresh view on FESOM2 optimization in general.


Cyprus Institute - Theo Christoudias
EMAC (ECHAM-MESSy Atmosphere Climate) model

The ECHAM/MESSy Atmospheric Chemistry (EMAC) model is a numerical chemistry and climate simulation system that includes sub-models describing tropospheric and middle atmosphere processes and their interaction with oceans, land and human influences.

Within the Earth System Chemistry Integrated Modelling (ESCIMo) initiative chemistry-climate-simulations are conducted by the MESSy Consortium with the EMAC model for special topics related to the national project of the DFG research unit Stratospheric Change and its Role for Climate Prediction (SHARP)  and the international IGAC/SPARC Chemistry-Climate Model Initiative (CCMI). These simulations will be carried out in support of upcoming WMO/UNEP ozone and IPCC climate assessments and will help to answer emerging science questions as well as to improve process understanding. Acceleration of the chemistry mechanism can reduce the number of CPU-nodes required and time-to-solution by a factor of 5 while using an atmospheric chemical mechanism (in terms of number of species and reactions) that is an order of magnitude more complex than the current state-of-the-art.

Delft University of Technology, Centrum Wiskunde & Informatica - Fredrik Jansson, Pier Siebesma
DALES - the Dutch Atmospheric Large Eddy Simulation

DALES is a large-eddy simulation code designed for studies of the physics of the atmospheric boundary layer, including convective and stable boundary layers as well as cloudy boundary layers. DALES can also be used for studying more specific cases, such as flow over sloping or heterogeneous terrain, and dispersion of inert and chemically active species.
The main goals of this new collaboration are 1) improving the scaling of DALES to many nodes and 2) improved single-threaded performance through more cache-friendly data-access patterns, potentially switching from double to single precision calculations, and improved numerical algorithms. The aim is that the optimizations get merged into the official DALES version, to be easily accessible for all users.

KNMI - Thomas Reerink

Ice caps are part of the climate system and interact with the atmosphere and the ocean via various feedback mechanisms. Ice sheet models need to be coupled with general circulation models (GCMs) in order to simulate the interactions between ice sheets, atmosphere, and ocean. Due to the type of the ice dynamic equations, ice sheet models use coordinate systems different from GCMs, requiring a projection and regridding or interpolation step. These and other specific GCM-ISM coupling issues are addressed by OBLIMAP.

This collaboration aims to develop a parallel implementation of OBLIMAP’s fast scan method and will serve the near-future demand of being capable to couple ice sheet modes, which are based on adaptive grids with GCMs. A parallel implementation of OBLIMAP’s fast mapping will improve the on-line mapping performance, which is interesting for high resolution (< 1km) applications. While OBLIMAP is ready for the major step to achieve on-line coupling of an ISM within an ESM, which has been a scientific goal for about 15 years now, the proposed parallel OBLIMAP release will significantly extend the number of more complex or high resolution applications.