Porting, Testing, Optimising, and Configuring the Community Earth System Model (CESM2) on ARCHER2
ARCHER2-eCSE03-06
PI: Dr Ioana Colfescu (National Centre for Atmospheric Science)
Co-Is: Dr Mike Mineter (University of Edinburgh), Dr Massimo Bollasina (University of Edinburgh), Dr. Wuhu Feng (National Centre for Atmospheric Science), Dr. Mark Richardson (University of Leeds), Dr Maria Val Martin (University of Sheffield), Dr Grenville MS Lister (National Centre for Atmospheric Science)
Technical staff: Dr Christopher C. Symonds (University of Leeds), Dr David H Case (National Centre for Atmospheric Science), Michael Bareford (EPCC, University of Edinburgh)
Subject Area:
The Community Earth System Model 2 (CESM2) is a world-leading global climate model. It is developed by the National Center for Atmospheric Research (NCAR) in the USA. NCAR provides not only the CESM2 code and support, but also various experiments and output, for two main purposes: to provide climate projections and predictions, and to make it usable as a state-of-the-art research tool. CESM2 is widely recognized and successfully used by the international research community. The availability of CESM2 to the UK research community opens up a wide range of avenues for various research directions, collaborations, and applications.
This project aimed at porting, optimising, testing, and validating the model’s key configurations and making them available to the UK community through ARCHER2, the UK National Supercomputing Service. A quick start guide, as well as the codes involved and documentation to set up experiments, have been now made available through the ARCHER2 website.
The availability of CESM2 on ARCHER2 has a broad array of benefits:
- It gives the opportunity to use a state-of-the-art climate model on a next-generation Supercomputing Service (see Figure 1 for a typical analysis of the model output).
- Given the wide range of ARCHER2 users in the UK, porting the model opens the potential for it to be used by a varied array of scientists in a multidisciplinary setting.
- It complements the models already deployed on ARCHER2 and expands the capability of UK scientists to study the causes of climate change.
- It facilitates the comparison between US and UK state-of-the-art models in order to reduce uncertainties in future climate projections.
- The ARCHER2 model configuration has been merged back to the NCAR repository and the proposal has been supported by NCAR; this created new links and opened new possibilities of collaboration with NCAR.
- It exploits the high level of parallelism provided by ARCHER2.
- Makes available documentation of ‘good practice’ (regarding methodologies for debugging, optimising, and tuning) with the relevant ARCHER2 tools made available through this work.
Figure 1: Climatological (30 year mean) annual mean precipitation (mm/day) simulated by CESM2 in its coupled configuration on ARCHER2.
Information about the code
The ESMF library was built and installed by CEMAC – downloaded 8.2.0 from the ESMF
The CESM2 software is downloaded by users and this eCSE work provides a machine-specific configuration for ARCHER2. With the addition of the ARCHER2 setup guide, the user has a more ARCHER2-centric guide to set up their installation than was previously available.