Technical Note: The Modular Earth Submodel System (MESSy) - a new approach towards Earth System Modeling

Abstract. The development of a comprehensive Earth System Model (ESM) to study the interactions between chemical, physical, and biological processes, requires coupling of the different domains (land, ocean, atmosphere, ...). One strategy is to link existing domain-specific models with a universal coupler, i.e. an independent standalone program organizing the communication between other programs. In many cases, however, a much simpler approach is more feasible. We have developed the Modular Earth Submodel System (MESSy). It comprises (1) a modular interface structure to connect to a , (2) an extendable set of such for miscellaneous processes, and (3) a coding standard. MESSy is therefore not a coupler in the classical sense, but exchanges data between a and several within one comprehensive executable. The internal complexity of the is controllable in a transparent and user friendly way. This provides remarkable new possibilities to study feedback mechanisms (by two-way coupling). Note that the MESSy and the coupler approach can be combined. For instance, an atmospheric model implemented according to the MESSy standard could easily be coupled to an ocean model by means of an external coupler. The vision is to ultimately form a comprehensive ESM which includes a large set of submodels, and a base model which contains only a central clock and runtime control. This can be reached stepwise, since each process can be included independently. Starting from an existing model, process submodels can be reimplemented according to the MESSy standard. This procedure guarantees the availability of a state-of-the-art model for scientific applications at any time of the development. In principle, MESSy can be implemented into any kind of model, either global or regional. So far, the MESSy concept has been applied to the general circulation model ECHAM5 and a number of process boxmodels.

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Technical Note: The Modular Earth Submodel System (MESSy) – a new approach towards Earth System Modeling

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-4-7139-2004 ◽

2004 ◽

Vol 4 (6) ◽

pp. 7139-7166

Author(s):

P. Jöckel ◽

R. Sander ◽

J. Lelieveld

Keyword(s):

General Circulation ◽

System Modeling ◽

Circulation Model ◽

Technical Note ◽

Biological Processes ◽

Earth System ◽

Earth System Modeling ◽

New Approach ◽

Domain Specific ◽

User Friendly

Abstract. Generally, the typical approach towards Earth System Modeling has been to couple existing models of different domains (land, ocean, atmosphere, ...) offline, using output files of one model to provide input for the other. However, for a detailed study of the interactions and feedbacks between chemical, physical, and biological processes, it is necessary to perform the coupling online. One strategy is to link the existing domain-specific models with a universal coupler. In many cases, however, a much simpler approach is more feasible. To achieve the online coupling, we have developed the Modular Earth Submodel System (MESSy). Data are exchanged between a and several within one comprehensive model system. MESSy includes a generalized interface structure for the standardized control of the and their interconnections. The internal complexity of the is controllable in a transparent and user friendly way. This provides remarkable new possibilities to study feedback mechanisms (by two-way coupling), e.g., by applying MESSy to a general circulation model (GCM).

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A clustering-based approach to ocean model–data comparison around Antarctica

Ocean Science ◽

10.5194/os-17-131-2021 ◽

2021 ◽

Vol 17 (1) ◽

pp. 131-145

Author(s):

Qiang Sun ◽

Christopher M. Little ◽

Alice M. Barthel ◽

Laurie Padman

Keyword(s):

General Circulation ◽

Water Mass ◽

Grid Point ◽

World Ocean ◽

Circulation Model ◽

Ocean Model ◽

Earth System ◽

Amundsen Sea ◽

Future Evolution ◽

Mean State

Abstract. The Antarctic Continental Shelf seas (ACSS) are a critical, rapidly changing element of the Earth system. Analyses of global-scale general circulation model (GCM) simulations, including those available through the Coupled Model Intercomparison Project, Phase 6 (CMIP6), can help reveal the origins of observed changes and predict the future evolution of the ACSS. However, an evaluation of ACSS hydrography in GCMs is vital: previous CMIP ensembles exhibit substantial mean-state biases (reflecting, for example, misplaced water masses) with a wide inter-model spread. Because the ACSS are also a sparely sampled region, grid-point-based model assessments are of limited value. Our goal is to demonstrate the utility of clustering tools for identifying hydrographic regimes that are common to different source fields (model or data), while allowing for biases in other metrics (e.g., water mass core properties) and shifts in region boundaries. We apply K-means clustering to hydrographic metrics based on the stratification from one GCM (Community Earth System Model version 2; CESM2) and one observation-based product (World Ocean Atlas 2018; WOA), focusing on the Amundsen, Bellingshausen and Ross seas. When applied to WOA temperature and salinity profiles, clustering identifies “primary” and “mixed” regimes that have physically interpretable bases. For example, meltwater-freshened coastal currents in the Amundsen Sea and a region of high-salinity shelf water formation in the southwestern Ross Sea emerge naturally from the algorithm. Both regions also exhibit clearly differentiated inner- and outer-shelf regimes. The same analysis applied to CESM2 demonstrates that, although mean-state model biases in water mass T–S characteristics can be substantial, using a clustering approach highlights that the relative differences between regimes and the locations where each regime dominates are well represented in the model. CESM2 is generally fresher and warmer than WOA and has a limited fresh-water-enriched coastal regimes. Given the sparsity of observations of the ACSS, this technique is a promising tool for the evaluation of a larger model ensemble (e.g., CMIP6) on a circum-Antarctic basis.

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GEOS-MITgcm coupled atmosphere-ocean simulation for DYAMOND

10.5194/egusphere-egu21-14947 ◽

2021 ◽

Author(s):

Ehud Strobach ◽

Andrea Molod ◽

Atanas Trayanov ◽

William Putman ◽

Dimitris Menemenlis ◽

...

Keyword(s):

General Circulation ◽

Circulation Model ◽

Atmospheric Model ◽

Ocean Model ◽

Second Phase ◽

Massachusetts Institute Of Technology ◽

Grid Spacing ◽

Institute Of Technology ◽

Horizontal Grid ◽

Ocean Simulation

During the past few years, the Goddard Earth Observing System (GEOS) and Massachusetts Institute of Technology general circulation model (MITgcm) groups have produced, respectively, global atmosphere-only and ocean-only simulations with km-scale grid spacing. These simulations have proved invaluable for process studies and the development of satellite and in-situ sampling strategies. Nevertheless, a key limitation of these simulations is the lack of feedback between the ocean and the atmosphere, limiting their usefulness for studying air-sea interactions and designing observing missions to study these interactions. To remove this limitation, we have coupled the km-scale GEOS atmospheric model with the km-scale MITgcm ocean model. We will present preliminary results from the GEOS-MITgcm contribution to the second phase of the DYAMOND (DYnamics of the Atmospheric general circulation Modeled On Non-hydrostatic Domains) initiative.The coupled atmosphere-ocean simulation was integrated using a cubed-sphere-1440 (~6-7 km horizontal grid spacing) configuration of GEOS and a lat-lon-cap-2160 (2&#8211;5-km horizontal grid spacing) configuration of MITgcm. We will show results from a preliminary analysis of air-sea interactions between Sea Surface Temperature (SST) and surface winds. In particular, we will discuss non-local atmospheric overturning circulation formed above the Gulf Stream SST front with characteristic sub-mesoscale width. This formation of a secondary circulation above the front suggests that capturing such air-sea interaction phenomena requires high-resolution capabilities in both the models' oceanic and atmospheric components.

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Coupled earth system modeling on heterogeneous HPC architectures with ParFlow in the Terrestrial Systems Modeling Platform

10.5194/egusphere-egu21-10831 ◽

2021 ◽

Author(s):

Jaro Hokkanen ◽

Stefan Kollet ◽

Jiri Kraus ◽

Andreas Herten ◽

Markus Hrywniak ◽

...

Keyword(s):

Land Surface ◽

Memory Management ◽

High Performance ◽

Data Exchange ◽

System Modeling ◽

Hydrologic Model ◽

Earth System ◽

Single Node ◽

Earth System Modeling ◽

Domain Specific

Rapidly changing heterogeneous supercomputer architectures pose a great challenge to many scientific communities trying to leverage the latest technology in high-performance computing. Implementations that simultaneously result in a good performance and developer productivity while keeping the codebase adaptable and well maintainable in the long-term are of high importance. ParFlow, a widely used hydrologic model, achieves these attributes by hiding the architecture-dependent code in preprocessor macros (ParFlow embedded Domain Specific Language, eDSL) and leveraging NVIDIA's Unified Memory technology for memory management. The implementation results in very good weak scaling with up to 26x speedup when using four NVIDIA A100 GPUs per node compared to using the available 48 CPU cores. Good weak scaling is observed using hundreds of nodes on the new JUWELS Booster system at the J&#252;lich Supercomputing Centre, Germany. Furthermore, it is possible to couple ParFlow with other earth system compartment models such as land surface and atmospheric models using the OASIS-MCT coupler library, which handles the data exchange between the different models. The ParFlow GPU implementation is fully compatible with the coupled implementation with little changes to the source code. Moreover, coupled simulations offer interesting load-balancing opportunities for optimal usage of the existing resources. For example, running ParFlow on GPU nodes, and another application component on CPU-only nodes, or efficiently distributing the CPU and GPU resources of a single node between the different application components may result in the best usage of heterogeneous architectures.

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AtMoDat: Improving the reusability of ATmospheric MOdel DATa with DataCite DOIs paving the path towards FAIR data

10.5194/egusphere-egu2020-8463 ◽

2020 ◽

Author(s):

Daniel Neumann ◽

Anette Ganske ◽

Vivien Voss ◽

Angelina Kraft ◽

Heinke Höck ◽

...

Keyword(s):

Quality Indicator ◽

System Modeling ◽

Atmospheric Model ◽

Atmospheric Modeling ◽

Research Data ◽

Earth System ◽

Model Data ◽

Earth System Modeling ◽

The Earth ◽

Generic Quality

The generation of high quality research data is expensive. The FAIR principles were established to foster the reuse of such data for the benefit of the scientific community and beyond. Publishing research data with metadata and DataCite DOIs in public repositories makes them findable and accessible (FA of FAIR). However, DOIs and basic metadata do not guarantee the data are actually reusable without discipline-specific knowledge: if data are saved in proprietary or undocumented file formats, if detailed discipline-specific metadata are missing and if quality information on the data and metadata are not provided. In this contribution, we present ongoing work in the AtMoDat project, -a consortium of atmospheric scientists and infrastructure providers, which aims on improving the reusability of atmospheric model data. &#160;&#160; Consistent standards are necessary to simplify the reuse of research data. Although standardization of file structure and metadata is well established for some subdomains of the earth system modeling community &#8211; e.g. CMIP &#8211;, several other subdomains are lacking such standardization. Hence, scientists from the Universities of Hamburg and Leipzig and infrastructure operators cooperate in the AtMoDat project in order to advance standardization for model output files in specific subdomains of the atmospheric modeling community. Starting from the demanding CMIP6 standard, the aim is to establish an easy-to-use standard that is at least compliant with the Climate and Forecast (CF) conventions. In parallel, an existing netCDF file convention checker is extended to check for the new standards. This enhanced checker is designed to support the creation of compliant files and thus lower the hurdle for data producers to comply with the new standard. The transfer of this approach to further sub-disciplines of the earth system modeling community will be supported by a best-practice guide and other documentation. A showcase of a standard for the urban atmospheric modeling community will be presented in this session. The standard is based on CF Conventions and adapts several global attributes and controlled vocabularies from the well-established CMIP6 standard. &#160;&#160; Additionally, the AtMoDat project aims on introducing a generic quality indicator into the DataCite metadata schema to foster further reuse of data. This quality indicator should require a discipline-specific implementation of a quality standard linked to the indicator. We will present the concept of the generic quality indicator in general and in the context of urban atmospheric modeling data.&#160;

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A clustering-based approach to ocean model-data comparison around Antarctica

10.5194/os-2020-51 ◽

2020 ◽

Author(s):

Qiang Sun ◽

Christopher M. Little ◽

Alice M. Barthel ◽

Laurie Padman

Keyword(s):

General Circulation ◽

World Ocean ◽

Circulation Model ◽

Ocean Model ◽

Coastal Current ◽

Earth System ◽

Model Data ◽

Amundsen Sea ◽

Data Comparison ◽

Mean State

Abstract. The Antarctic Continental Shelf Seas (ACSS) are a critical, rapidly-changing element of the Earth system. Analyses of global-scale general circulation model (GCM) simulations, including those available through the Coupled Model Intercomparison Project, Phase 6 (CMIP6), can help reveal the origins of observed changes and predict the future evolution of the ACSS. However, an evaluation of ACSS hydrography in GCMs is vital: previous CMIP ensembles exhibit substantial mean-state biases (reflecting, for example, misplaced water masses) with a wide inter-model spread. Here, we demonstrate the utility of clustering tools for the identification and model-data comparison of hydrographic regimes. In this proof-of-concept analysis, we apply K-means clustering to hydrographic metrics from one GCM (Community Earth System Model version 2; CESM2) and one observation-based product (World Ocean Atlas 2018; WOA), focusing on the Amundsen, Bellingshausen, and Ross Seas. When applied to WOA temperature and salinity profiles, clustering identifies source and mixed regimes that have a physically interpretable basis. For example, meltwater-freshened coastal currents in the Amundsen Sea, and high salinity shelf water formation regions in the southwestern Ross Sea, emerge naturally from the algorithm. Both regions also exhibit clearly differentiated inner- and outer-shelf regimes. The same analysis applied to CESM2 demonstrates that, although mean-state model bias can be substantial, using a clustering approach highlights that the relative differences between regimes, and the locations where each regime dominates, are well represented in the model. CESM2 is generally fresher and warmer than WOA and lacks a clearly defined fresh-water-enriched coastal current. Given the sparsity of observations on the ACSS, this technique is a promising tool for the evaluation of a larger model ensemble (e.g., CMIP6) on a circum-Antarctic basis.

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