scholarly journals Next generation framework for aquatic modeling of the Earth System

2009 ◽  
Vol 2 (1) ◽  
pp. 279-307 ◽  
Author(s):  
B. M. Fekete ◽  
W. M. Wollheim ◽  
D. Wisser ◽  
C. J. Vörösmarty
Keyword(s):  
Model Development ◽  
Learning Curves ◽  
Earth System ◽  
Next Generation ◽  
Model Calculations ◽  
System Models ◽  
The Earth ◽  
Wide Range ◽  
Spatial Domains ◽  
Earth System Models

Abstract. Earth System model development is becoming an increasingly complex task. As scientists attempt to represent the physical and bio-geochemical processes and various feedback mechanisms in unprecedented detail, the models themselves are becoming increasingly complex. At the same time, the complexity of the surrounding IT infrastructure is growing as well. Earth System models must manage a vast amount of data in heterogeneous computing environments. Numerous development efforts are on the way to ease that burden and offer model development platforms that reduce IT challenges and allow scientists to focus on their science. While these new modeling frameworks (e.g. FMS, ESMF, CCA, OpenMI) do provide solutions to many IT challenges (performing input/output, managing space and time, establishing model coupling, etc.), they are still considerably complex and often have steep learning curves. The Next generation Framework for Aquatic Modeling of the Earth System (NextFrAMES, a revised version of FrAMES) have numerous similarities to those developed by other teams, but represents a novel model development paradigm. NextFrAMES is built around a modeling XML that lets modelers to express the overall model structure and provides an API for dynamically linked plugins to represent the processes. The model XML is executed by the NextFrAMES run-time engine that parses the model definition, loads the module plugins, performs the model I/O and executes the model calculations. NextFrAMES has a minimalistic view representing spatial domains and treats every domain (regardless of its layout such as grid, network tree, individual points, polygons, etc.) as vector of objects. NextFrAMES performs computations on multiple domains and interactions between different spatial domains are carried out through couplers. NextFrAMES allows processes to operate at different frequencies by providing rudimentary aggregation and disaggregation facilities. NextFrAMES was designed primarily for hydrological modeling purposes, but many of its functionality should be applicable for a wide range of land surface models. In its present capabilities NextFrAMES is probably inadequate to implement fully coupled Earth System models, but future versions with the guidance from Earth System developers might someday eliminate its limitations. Our intent with NextFrAMES is to initiate a dialog about new ways of expressing models that is less tied to the actual implementation and allow scientist to develop models at a more abstract level.

An Overview of Parameterezations of Heat Transfer over Moss-Covered Surfaces in the Earth System Models

2020 ◽  
Vol 56 (2) ◽  
pp. 101-111
Author(s):  
V. M. Stepanenko ◽  
I. A. Repina ◽  
V. E. Fedosov ◽  
S. S. Zilitinkevich ◽  
V. N. Lykossov
Keyword(s):  
Heat Transfer ◽  
Earth System ◽  
System Models ◽  
The Earth ◽  
Earth System Models

scholarly journals OMEN-SED 0.9: A novel, numerically efficient organic matter sediment diagenesis module for coupling to Earth system models

2018 ◽  
Author(s):  
Dominik Hülse ◽  
Sandra Arndt ◽  
Stuart Daines ◽  
Pierre Regnier ◽  
Andy Ridgwell
Keyword(s):  
Organic Matter ◽  
Marine Sediments ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Model Framework ◽  
System Models ◽  
Wide Range ◽  
Earth System Models ◽  
Sediment Model

Abstract. We present the first version of OMEN-SED (Organic Matter ENabled SEDiment model), a new, one-dimensional analytical early diagenetic model resolving organic matter cycling and associated biogeochemical dynamics in marine sediments designed to be coupled to Earth system models. OMEN-SED explicitly describes organic matter (OM) cycling as well as associated dynamics of the most important terminal electron acceptors (i.e. O2, NO3, SO4) and methane (CH4), related reduced substances (NH4, H2S), macronutrients (PO4) and associated pore water quantities (ALK, DIC). Its reaction network accounts for the most important primary and secondary redox reactions, equilibrium reactions, mineral dissolution and precipitation, as well as adsorption and desorption processes associated with OM dynamics that affect the dissolved and solid species explicitly resolved in the model. To represent a redox-dependent sedimentary P cycle we also include a representation of the formation and burial of Fe-bound P and authigenic Ca-P minerals. Thus, OMEN-SED is able to capture the main features of diagenetic dynamics in marine sediments and, therefore, offers similar predictive abilities than a complex, numerical diagenetic model. Yet, its computational efficiency allows its coupling to global Earth system models and therefore the investigation of coupled global biogeochemical dynamics over a wide range of climate relevant timescales. This paper provides a detailed description of the new sediment model, an extensive sensitivity analysis, as well as an evaluation of OMEN-SED's performance through comprehensive comparisons with observations and results from a more complex numerical model. We find solid phase and dissolved pore water profiles for different ocean depths are reproduced with good accuracy and simulated terminal electron acceptor fluxes fall well within the range of globally observed fluxes. Finally, we illustrate its application in an Earth system model framework by coupling OMEN-SED to the Earth system model cGENIE and tune the OM degradation rate constants to optimise the fit of simulated benthic OM contents to global observations. We find simulated sediment characteristics of the coupled model framework, such as OM degradation rates, oxygen penetration depths and sediment-water interface fluxes are generally in good agreement with observations and in line with what one would expect on a global scale. Coupled to an Earth system model, OMEN-SED is thus a powerful tool that will not only help elucidate the role of benthic-pelagic exchange processes in the evolution and, in particular, the termination of a wide range of climate events, but will also allow a direct comparison of model output with the sedimentary record – the most important climate archive on Earth.

Using objective comparisons of observed and simulated precipitation to help guide the improvement of Earth System Models

2020 ◽  
Author(s):  
Peter Gleckler ◽  
Angeline Pendergrass
Keyword(s):  
Model Development ◽  
Model Performance ◽  
Source Analysis ◽  
Earth System ◽  
Frequency Distributions ◽  
System Models ◽  
Simulated Precipitation ◽  
Tiered System ◽  
Earth System Models

<p>In this presentation we discuss a community-based effort to establish the benchmarking of simulated precipitation in Earth System Models.   We first summarize the impetus and outcomes of a recent workshop dedicated to the topic.    This includes the identification of a tiered system of objective tests (metrics) for the following climatological characteristics:  the mean state, seasonal cycle, variability across time scales, intensity/frequency distributions, extremes and drought.   Preliminary results are shown gauging model performance changes across multiple generations of CMIP.   The performance tests we describe are part of an open-source analysis framework being made available to model developers to help them make judgements about the quality of simulated precipitation during the model development process.</p>

scholarly journals Physically regularized machine learning emulators of aerosol activation

2021 ◽  
Vol 14 (5) ◽  
pp. 3067-3077
Author(s):  
Sam J. Silva ◽  
Po-Lun Ma ◽  
Joseph C. Hardin ◽  
Daniel Rothenberg
Keyword(s):  
Machine Learning ◽  
Model Development ◽  
Computational Cost ◽  
Earth System ◽  
Cloud Droplets ◽  
Physical Constraints ◽  
System Models ◽  
Machine Learning Model ◽  
Aerosol Activation ◽  
Earth System Models

Abstract. The activation of aerosol into cloud droplets is an important step in the formation of clouds and strongly influences the radiative budget of the Earth. Explicitly simulating aerosol activation in Earth system models is challenging due to the computational complexity required to resolve the necessary chemical and physical processes and their interactions. As such, various parameterizations have been developed to approximate these details at reduced computational cost and accuracy. Here, we explore how machine learning emulators can be used to bridge this gap in computational cost and parameterization accuracy. We evaluate a set of emulators of a detailed cloud parcel model using physically regularized machine learning regression techniques. We find that the emulators can reproduce the parcel model at higher accuracy than many existing parameterizations. Furthermore, physical regularization tends to improve emulator accuracy, most significantly when emulating very low activation fractions. This work demonstrates the value of physical constraints in machine learning model development and enables the implementation of improved hybrid physical and machine learning models of aerosol activation into next-generation Earth system models.

scholarly journals Lineage Functional Types (LFTs): Characterizing functional diversity to enhance the representation of ecological behavior in Earth System Models

2020 ◽  
Author(s):  
Daniel M. Griffith ◽  
Colin Osborne ◽  
Erika J. Edwards ◽  
Seton Bachle ◽  
David J. Beerling ◽  
...  
Keyword(s):  
Functional Diversity ◽  
Species Level ◽  
Earth System ◽  
Trait Variation ◽  
System Models ◽  
Biogeographic History ◽  
Functional Types ◽  
Wide Range ◽  
Vegetation Models ◽  
Earth System Models

SummaryProcess-based vegetation models attempt to represent the wide range of trait variation in biomes by grouping ecologically similar species into plant functional types (PFTs). This approach has been successful in representing many aspects of plant physiology and biophysics, but struggles to capture biogeographic history and ecological dynamics that determine biome boundaries and plant distributions. Grass dominated ecosystems are broadly distributed across all vegetated continents and harbor large functional diversity, yet most Earth System Models (ESMs) summarize grasses into two generic PFTs based primarily on differences between temperate C3 grasses and (sub)tropical C4 grasses. Incorporation of species-level trait variation is an active area of research to enhance the ecological realism of PFTs, which form the basis for vegetation processes and dynamics in ESMs. Using reported measurements, we developed grass functional trait values (physiological, structural, biochemical, anatomical, phenological, and disturbance-related) of dominant lineages to improve ESM representations. Our method is fundamentally different from previous efforts, as it uses phylogenetic relatedness to create lineage-based functional types (LFTs), situated between species-level trait data and PFT-level abstractions, thus providing a realistic representation of functional diversity and opening the door to the development of new vegetation models.

scholarly journals Causes of uncertainty in observed and projected heterotrophic respiration from Earth System Models

2017 ◽  
Author(s):  
Cary Lynch ◽  
Corinne Hartin ◽  
Min Chen ◽  
Ben Bond-Lamberty
Keyword(s):  
Model Development ◽  
Coupled Model ◽  
Surface Air Temperature ◽  
Heterotrophic Respiration ◽  
Climate Variables ◽  
Earth System ◽  
System Models ◽  
Scenario Evaluation ◽  
Statistical Relationships ◽  
Earth System Models

Abstract. Heterotrophic respiration (RH) is a large component of the terrestrial carbon cycle, but one poorly simulated by Earth system models (ESMs), which diverge significantly in their historical and future RH projections. There is little understanding, however, of the causes of this variability and its consequences for future model development and scenario evaluation, and examining the relationships between RH and key climate variables may help to understand where and why models are divergent. We quantified the statistical relationships between RH and other terrestrial/climate variables across a suite of 25 ESMs from the Coupled Model Intercomparison Project phase 5 (CMIP5) for the 20th and 21st centuries, comparing the models both to each other and to an observation-driven global RH dataset. Compared to observations, ESMs consistency overestimate both the magnitude and climate sensitivity of global RH. The relationship between RH and surface air temperature (TAS) is strong, especially at high latitudes, and largely consistent across models. The observed RH and precipitation (PR) relationship is strong and positive (r ≥ 0.5, P 

scholarly journals Evaluation of biospheric components in Earth system models using modern and palaeo observations: the state-of-the-art

2013 ◽  
Vol 10 (7) ◽  
pp. 10937-10995 ◽  
Author(s):  
A. M. Foley ◽  
D. Dalmonech ◽  
A. D. Friend ◽  
F. Aires ◽  
A. Archibald ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Model Evaluation ◽  
State Of The Art ◽  
The State ◽  
System Level ◽  
Earth System ◽  
Evaluation Methodologies ◽  
System Models ◽  
Wide Range ◽  
Earth System Models

Abstract. Earth system models are increasing in complexity and incorporating more processes than their predecessors, making them important tools for studying the global carbon cycle. However, their coupled behaviour has only recently been examined in any detail, and has yielded a very wide range of outcomes, with coupled climate-carbon cycle models that represent land-use change simulating total land carbon stores by 2100 that vary by as much as 600 Pg C given the same emissions scenario. This large uncertainty is associated with differences in how key processes are simulated in different models, and illustrates the necessity of determining which models are most realistic using rigorous model evaluation methodologies. Here we assess the state-of-the-art with respect to evaluation of Earth system models, with a particular emphasis on the simulation of the carbon cycle and associated biospheric processes. We examine some of the new advances and remaining uncertainties relating to (i) modern and palaeo data and (ii) metrics for evaluation, and discuss a range of strategies, such as the inclusion of pre-calibration, combined process- and system-level evaluation, and the use of emergent constraints, that can contribute towards the development of more robust evaluation schemes. An increasingly data-rich environment offers more opportunities for model evaluation, but it is also a challenge, as more knowledge about data uncertainties is required in order to determine robust evaluation methodologies that move the field of ESM evaluation from "beauty contest" toward the development of useful constraints on model behaviour.

scholarly journals Ideas and perspectives: climate-relevant marine biologically driven mechanisms in Earth system models

2017 ◽  
Vol 14 (2) ◽  
pp. 403-413 ◽  
Author(s):  
Inga Hense ◽  
Irene Stemmler ◽  
Sebastian Sonntag
Keyword(s):  
Atmospheric Composition ◽  
Climate Projections ◽  
Marine Biota ◽  
Earth System ◽  
System Models ◽  
The Earth ◽  
Optical And Mechanical Properties ◽  
System 1 ◽  
Earth System Models

Abstract. The current generation of marine biogeochemical modules in Earth system models (ESMs) considers mainly the effect of marine biota on the carbon cycle. We propose to also implement other biologically driven mechanisms in ESMs so that more climate-relevant feedbacks are captured. We classify these mechanisms in three categories according to their functional role in the Earth system: (1) biogeochemical pumps, which affect the carbon cycling; (2) biological gas and particle shuttles, which affect the atmospheric composition; and (3) biogeophysical mechanisms, which affect the thermal, optical, and mechanical properties of the ocean. To resolve mechanisms from all three classes, we find it sufficient to include five functional groups: bulk phyto- and zooplankton, calcifiers, and coastal gas and surface mat producers. We strongly suggest to account for a larger mechanism diversity in ESMs in the future to improve the quality of climate projections.

scholarly journals ESMValTool (v1.0) – a community diagnostic and performance metrics tool for routine evaluation of Earth System Models in CMIP

2015 ◽  
Vol 8 (9) ◽  
pp. 7541-7661 ◽  
Author(s):  
V. Eyring ◽  
M. Righi ◽  
M. Evaldsson ◽  
A. Lauer ◽  
S. Wenzel ◽  
...  
Keyword(s):  
Performance Metrics ◽  
Stratospheric Ozone ◽  
Coupled Model ◽  
Earth System ◽  
Evaluation Tool ◽  
System Models ◽  
The Earth ◽  
Systematic Biases ◽  
And Performance ◽  
Earth System Models

Abstract. A community diagnostics and performance metrics tool for the evaluation of Earth System Models (ESMs) has been developed that allows for routine comparison of single or multiple models, either against predecessor versions or against observations. The priority of the effort so far has been to target specific scientific themes focusing on selected Essential Climate Variables (ECVs), a range of known systematic biases common to ESMs, such as coupled tropical climate variability, monsoons, Southern Ocean processes, continental dry biases and soil hydrology-climate interactions, as well as atmospheric CO2 budgets, tropospheric and stratospheric ozone, and tropospheric aerosols. The tool is being developed in such a way that additional analyses can easily be added. A set of standard namelists for each scientific topic reproduces specific sets of diagnostics or performance metrics that have demonstrated their importance in ESM evaluation in the peer-reviewed literature. The Earth System Model Evaluation Tool (ESMValTool) is a community effort open to both users and developers encouraging open exchange of diagnostic source code and evaluation results from the CMIP ensemble. This will facilitate and improve ESM evaluation beyond the state-of-the-art and aims at supporting such activities within the Coupled Model Intercomparison Project (CMIP) and at individual modelling centres. Ultimately, we envisage running the ESMValTool alongside the Earth System Grid Federation (ESGF) as part of a more routine evaluation of CMIP model simulations while utilizing observations available in standard formats (obs4MIPs) or provided by the user.

scholarly journals Mapping past human land use using archaeological data: A new classification for global land use synthesis and data harmonization

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0246662 ◽  
Author(s):  
Kathleen D. Morrison ◽  
Emily Hammer ◽  
Oliver Boles ◽  
Marco Madella ◽  
Nicola Whitehouse ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Classification Scheme ◽  
Earth System ◽  
Land Use Systems ◽  
System Models ◽  
The Past ◽  
The Earth ◽  
Earth System Models ◽  
Past Land Use

In the 12,000 years preceding the Industrial Revolution, human activities led to significant changes in land cover, plant and animal distributions, surface hydrology, and biochemical cycles. Earth system models suggest that this anthropogenic land cover change influenced regional and global climate. However, the representation of past land use in earth system models is currently oversimplified. As a result, there are large uncertainties in the current understanding of the past and current state of the earth system. In order to improve representation of the variety and scale of impacts that past land use had on the earth system, a global effort is underway to aggregate and synthesize archaeological and historical evidence of land use systems. Here we present a simple, hierarchical classification of land use systems designed to be used with archaeological and historical data at a global scale and a schema of codes that identify land use practices common to a range of systems, both implemented in a geospatial database. The classification scheme and database resulted from an extensive process of consultation with researchers worldwide. Our scheme is designed to deliver consistent, empirically robust data for the improvement of land use models, while simultaneously allowing for a comparative, detailed mapping of land use relevant to the needs of historical scholars. To illustrate the benefits of the classification scheme and methods for mapping historical land use, we apply it to Mesopotamia and Arabia at 6 kya (c. 4000 BCE). The scheme will be used to describe land use by the Past Global Changes (PAGES) LandCover6k working group, an international project comprised of archaeologists, historians, geographers, paleoecologists, and modelers. Beyond this, the scheme has a wide utility for creating a common language between research and policy communities, linking archaeologists with climate modelers, biodiversity conservation workers and initiatives.

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