scholarly journals A JavaScript API for the Ice Sheet System Model: towards on online interactive model for the Cryosphere Community

2016 ◽  
Author(s):  
Eric Larour ◽  
Daniel Cheng ◽  
Gilberto Perez ◽  
Justin Quinn ◽  
Mathieu Morlighem ◽  
...  
Keyword(s):  
High Performance ◽  
Ice Sheet ◽  
System Model ◽  
Earth System ◽  
Efficient Manner ◽  
Post Process ◽  
Software Model ◽  
Science Community ◽  
Deep Integration ◽  
Client Side

Abstract. Earth System Models (ESMs) are becoming increasingly complex, requiring extensive knowledge and experience to deploy and use in an efficient manner. They run on high-performance architectures that are significantly different from the everyday environments that scientists use to pre and post-process results (i.e. MATLAB, Python). This results in models that are hard to use for non specialists, and that are increasingly specific in their application. It also makes them relatively inaccessible to the wider science community, not to mention to the general public. Here, we present a new software/model paradigm that attempts to bridge the gap between the science community and the complexity of ESMs, by developing a new JavaScript Application Program Interface (API) for the Ice Sheet System Model (ISSM). The aforementioned API allows Cryosphere Scientists to run ISSM on the client-side of a webpage, within the JavaScript environment. When combined with a Web server running ISSM (using a Python API), it enables the serving of ISSM computations in an easy and straightforward way. The deep integration and similarities between all the APIs in ISSM (MATLAB, Python, and now JavaScript) significantly shortens and simplifies the turnaround of state-of-the-art science runs and their use by the larger community. We demonstrate our approach via a new Virtual Earth System Laboratory (VESL) Web site.

scholarly journals A JavaScript API for the Ice Sheet System Model (ISSM) 4.11: towards an online interactive model for the cryosphere community

2017 ◽  
Vol 10 (12) ◽  
pp. 4393-4403 ◽  
Author(s):  
Eric Larour ◽  
Daniel Cheng ◽  
Gilberto Perez ◽  
Justin Quinn ◽  
Mathieu Morlighem ◽  
...  
Keyword(s):  
High Performance ◽  
Ice Sheet ◽  
System Model ◽  
Earth System ◽  
Efficient Manner ◽  
Post Process ◽  
Software Model ◽  
Science Community ◽  
Deep Integration ◽  
Client Side

Abstract. Earth system models (ESMs) are becoming increasingly complex, requiring extensive knowledge and experience to deploy and use in an efficient manner. They run on high-performance architectures that are significantly different from the everyday environments that scientists use to pre- and post-process results (i.e., MATLAB, Python). This results in models that are hard to use for non-specialists and are increasingly specific in their application. It also makes them relatively inaccessible to the wider science community, not to mention to the general public. Here, we present a new software/model paradigm that attempts to bridge the gap between the science community and the complexity of ESMs by developing a new JavaScript application program interface (API) for the Ice Sheet System Model (ISSM). The aforementioned API allows cryosphere scientists to run ISSM on the client side of a web page within the JavaScript environment. When combined with a web server running ISSM (using a Python API), it enables the serving of ISSM computations in an easy and straightforward way. The deep integration and similarities between all the APIs in ISSM (MATLAB, Python, and now JavaScript) significantly shortens and simplifies the turnaround of state-of-the-art science runs and their use by the larger community. We demonstrate our approach via a new Virtual Earth System Laboratory (VESL) website (http://vesl.jpl.nasa.gov, VESL(2017)).

scholarly journals Mechanisms and time scales of glacial inception simulated with an Earth system model of intermediate complexity

2009 ◽  
Vol 5 (2) ◽  
pp. 245-258 ◽  
Author(s):  
R. Calov ◽  
A. Ganopolski ◽  
C. Kubatzki ◽  
M. Claussen
Keyword(s):  
Transient Response ◽  
Ice Sheet ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Intermediate Complexity ◽  
Transient Simulations ◽  
Ice Sheet Dynamics ◽  
Inland Ice ◽  
Equilibrium Simulation

Abstract. We investigate glacial inception and glacial thresholds in the climate-cryosphere system utilising the Earth system model of intermediate complexity CLIMBER-2, which includes modules for atmosphere, terrestrial vegetation, ocean and interactive ice sheets. The latter are described by the three-dimensional polythermal ice-sheet model SICOPOLIS. A bifurcation which represents glacial inception is analysed with two different model setups: one setup with dynamical ice-sheet model and another setup without it. The respective glacial thresholds differ in terms of maximum boreal summer insolation at 65° N (hereafter referred as Milankovitch forcing (MF)). The glacial threshold of the configuration without ice-sheet dynamics corresponds to a much lower value of MF compared to the full model. If MF attains values only slightly below the aforementioned threshold there is fast transient response. Depending on the value of MF relative to the glacial threshold, the transient response time of inland-ice volume in the model configuration with ice-sheet dynamics ranges from 10 000 to 100 000 years. Due to these long response times, a glacial threshold obtained in an equilibrium simulation is not directly applicable to the transient response of the climate-cryosphere system to time-dependent orbital forcing. It is demonstrated that in transient simulations just crossing of the glacial threshold does not imply large-scale glaciation of the Northern Hemisphere. We found that in transient simulations MF has to drop well below the glacial threshold determined in an equilibrium simulation to initiate glacial inception. Finally, we show that the asynchronous coupling between climate and inland-ice components allows one sufficient realistic simulation of glacial inception and, at the same time, a considerable reduction of computational costs.

scholarly journals MPAS-Albany Land Ice (MALI): A variable resolution ice sheet model for Earth system modeling using Voronoi grids

2018 ◽  
Author(s):  
Matthew J. Hoffman ◽  
Mauro Perego ◽  
Stephen F. Price ◽  
William H. Lipscomb ◽  
Douglas Jacobsen ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Earth System Model ◽  
Coupled Systems ◽  
System Model ◽  
Type Model ◽  
Earth System ◽  
Ice Dynamics ◽  
Variable Resolution ◽  
Horizontal Advection ◽  
First Order

Abstract. We introduce MPAS-Albany Land Ice (MALI), a new, variable resolution land ice model that uses unstructured Voronoi grids on a plane or sphere. MALI is built using the Model for Prediction Across Scales (MPAS) framework for developing variable resolution Earth System Model components and the Albany multi-physics code base for solution of coupled systems of partial-differential equations, which itself makes use of Trilinos solver libraries. MALI includes a three-dimensional, first-order momentum balance solver ("Blatter-Pattyn") by linking to the Albany-LI ice sheet velocity solver, as well as an explicit shallow ice velocity solver. Evolution of ice geometry and tracers is handled through an explicit first-order horizontal advection scheme with vertical remapping. Evolution of ice temperature is treated using operator splitting of vertical diffusion and horizontal advection and can be configured to use either a temperature or enthalpy formulation. MALI includes a mass-conserving subglacial hydrology model that supports distributed and/or channelized drainage and can optionally be coupled to ice dynamics. Options for calving include "eigencalving", which assumes calving rate is proportional to extensional strain rates. MALI is evaluated against commonly used exact solutions and community benchmark experiments and shows the expected accuracy. We report first results for the MISMIP3d benchmark experiments for a Blatter-Pattyn type model and show that results fall in-between those of models using Stokes flow and L1L2 approximations. We use the model to simulate a semi-realistic Antarctic Ice Sheet problem for 1100 years at 20 km resolution. MALI is the glacier component of the Energy Exascale Earth System Model (E3SM) version 1, and we describe current and planned coupling to other components.

scholarly journals Incorporation of ice sheet models into an Earth system model: Focus on methodology of coupling

2018 ◽  
Vol 127 (2) ◽  
Author(s):  
Oleg Rybak ◽  
Evgeny Volodin ◽  
Polina Morozova ◽  
Artiom Nevecherja
Keyword(s):  
Ice Sheet ◽  
Earth System Model ◽  
System Model ◽  
Earth System

scholarly journals Greenland Surface Mass Balance as Simulated by the Community Earth System Model. Part II: Twenty-First-Century Changes

2014 ◽  
Vol 27 (1) ◽  
pp. 215-226 ◽  
Author(s):  
Miren Vizcaíno ◽  
William H. Lipscomb ◽  
William J. Sacks ◽  
Michiel van den Broeke
Keyword(s):  
Mass Balance ◽  
Ice Sheet ◽  
Earth System Model ◽  
First Century ◽  
System Model ◽  
Surface Mass Balance ◽  
Earth System ◽  
Surface Mass ◽  
Community Earth System Model ◽  
Twenty First Century

Abstract This study presents the first twenty-first-century projections of surface mass balance (SMB) changes for the Greenland Ice Sheet (GIS) with the Community Earth System Model (CESM), which includes a new ice sheet component. For glaciated surfaces, CESM includes a sophisticated calculation of energy fluxes, surface albedo, and snowpack hydrology (melt, percolation, refreezing, etc.). To efficiently resolve the high SMB gradients at the ice sheet margins and provide surface forcing at the scale needed by ice sheet models, the SMB is calculated at multiple elevations and interpolated to a finer 5-km ice sheet grid. During a twenty-first-century simulation driven by representative concentration pathway 8.5 (RCP8.5) forcing, the SMB decreases from 372 ± 100 Gt yr−1 in 1980–99 to −78 ± 143 Gt yr−1 in 2080–99. The 2080–99 near-surface temperatures over the GIS increase by 4.7 K (annual mean) with respect to 1980–99, only 1.3 times the global increase (+3.7 K). Snowfall increases by 18%, while surface melt doubles. The ablation area increases from 9% of the GIS in 1980–99 to 28% in 2080–99. Over the ablation areas, summer downward longwave radiation and turbulent fluxes increase, while incoming shortwave radiation decreases owing to increased cloud cover. The reduction in GIS-averaged July albedo from 0.78 in 1980–99 to 0.75 in 2080–99 increases the absorbed solar radiation in this month by 12%. Summer warming is strongest in the north and east of Greenland owing to reduced sea ice cover. In the ablation area, summer temperature increases are smaller due to frequent periods of surface melt.

scholarly journals MPAS-Albany Land Ice (MALI): a variable-resolution ice sheet model for Earth system modeling using Voronoi grids

2018 ◽  
Vol 11 (9) ◽  
pp. 3747-3780 ◽  
Author(s):  
Matthew J. Hoffman ◽  
Mauro Perego ◽  
Stephen F. Price ◽  
William H. Lipscomb ◽  
Tong Zhang ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Earth System Model ◽  
Coupled Systems ◽  
System Model ◽  
Momentum Balance ◽  
Earth System ◽  
Ice Dynamics ◽  
Variable Resolution ◽  
Horizontal Advection ◽  
First Order

Abstract. We introduce MPAS-Albany Land Ice (MALI) v6.0, a new variable-resolution land ice model that uses unstructured Voronoi grids on a plane or sphere. MALI is built using the Model for Prediction Across Scales (MPAS) framework for developing variable-resolution Earth system model components and the Albany multi-physics code base for the solution of coupled systems of partial differential equations, which itself makes use of Trilinos solver libraries. MALI includes a three-dimensional first-order momentum balance solver (Blatter–Pattyn) by linking to the Albany-LI ice sheet velocity solver and an explicit shallow ice velocity solver. The evolution of ice geometry and tracers is handled through an explicit first-order horizontal advection scheme with vertical remapping. The evolution of ice temperature is treated using operator splitting of vertical diffusion and horizontal advection and can be configured to use either a temperature or enthalpy formulation. MALI includes a mass-conserving subglacial hydrology model that supports distributed and/or channelized drainage and can optionally be coupled to ice dynamics. Options for calving include “eigencalving”, which assumes that the calving rate is proportional to extensional strain rates. MALI is evaluated against commonly used exact solutions and community benchmark experiments and shows the expected accuracy. Results for the MISMIP3d benchmark experiments with MALI's Blatter–Pattyn solver fall between published results from Stokes and L1L2 models as expected. We use the model to simulate a semi-realistic Antarctic ice sheet problem following the initMIP protocol and using 2 km resolution in marine ice sheet regions. MALI is the glacier component of the Energy Exascale Earth System Model (E3SM) version 1, and we describe current and planned coupling to other E3SM components.

scholarly journals Calculation of mass discharge of the Greenland ice sheet in the Earth System Model

2016 ◽  
Vol 56 (3) ◽  
pp. 293-308 ◽  
Author(s):  
O. O. Rybak ◽  
E. M. Volodin ◽  
A. P. Nevecherya ◽  
P. A. Morozova ◽  
M. M. Кaminskaya
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
The Earth ◽  
Mass Discharge

Simulation of LGM ice sheets with the Community Earth System Model version 2 

2021 ◽  
Author(s):  
Sarah L Bradley ◽  
Michele Petrini ◽  
Raymond Sellevold ◽  
Miren Vizcaino ◽  
William H. Lipscomb ◽  
...  
Keyword(s):  
Ice Sheets ◽  
Ice Sheet ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Last Deglaciation ◽  
Model Version ◽  
Starting Point ◽  
Community Earth System Model ◽  
The Last Deglaciation

<p>The last deglaciation provides as unique a framework to investigate the processes of ice sheet and climate interaction during periods of mass loss as in the current climate. Here we simulate the Last Glacial Maximum (LGM) northern hemisphere ice sheets climate, surface mass balance (SMB), and dynamics with the Community Earth System Model version 2 (CESM2, Danabasoglu et al., 2020)) and the Community Ice Sheet Model version 2 (CISM2, Lipscomb et al., 2019). This LGM simulation will be later used as starting point for coupled CESM2-CISM2 simulations of the last deglaciation.</p><p> </p><p>CESM2 is run at the nominal resolution used for IPCC-type projections (approx. 1 degree for all components). The model includes an advanced snow/firn and SMB calculation (van Kampenhout et al, 2019; Sellevold et al, 2019) the land component (CLM, cite) that has been evaluated and applied to the simulation of the future Greenland melt (van Kampenhout et al, 2020, Muntjewerf et al., 2020a,b, Sellevold & Vizcaino, 2020).</p><p> </p><p>Our analysis examines how the global, Arctic, and North Atlantic climate result in the simulated radiative and turbulent heat fluxes over the ice sheets, and the mass fluxes from precipitation, refreezing, runoff, and sublimation. We also examine the simulated ice streams in CISM2, which is run at 8 km under a higher-order approximation for ice flow.</p>

scholarly journals LIVVkit 2.1: automated and extensible ice sheet model validation

2019 ◽  
Vol 12 (3) ◽  
pp. 1067-1086 ◽  
Author(s):  
Katherine J. Evans ◽  
Joseph H. Kennedy ◽  
Dan Lu ◽  
Mary M. Forrester ◽  
Stephen Price ◽  
...  
Keyword(s):  
Land Surface ◽  
High Performance ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Earth System ◽  
Remotely Sensed Data ◽  
Surface Mass ◽  
Community Earth System Model ◽  
Southwest Region ◽  
Temperature Radiation

Abstract. A collection of scientific analyses, metrics, and visualizations for robust validation of ice sheet models is presented using the Land Ice Verification and Validation toolkit (LIVVkit), version 2.1, and the LIVVkit Extensions repository (LEX), version 0.1. This software collection targets stand-alone ice sheet or coupled Earth system models, and handles datasets and analyses that require high-performance computing and storage. LIVVkit aims to enable efficient and fully reproducible workflows for postprocessing, analysis, and visualization of observational and model-derived datasets in a shareable format, whereby all data, methodologies, and output are distributed to users for evaluation. Extending from the initial LIVVkit software framework, we demonstrate Greenland ice sheet simulation validation metrics using the coupled Community Earth System Model (CESM) as well as an idealized stand-alone high-resolution Community Ice Sheet Model, version 2 (CISM2), coupled to the Albany/FELIX velocity solver (CISM-Albany or CISM-A). As one example of the capability, LIVVkit analyzes the degree to which models capture the surface mass balance (SMB) and identifies potential sources of bias, using recently available in situ and remotely sensed data as comparison. Related fields within atmosphere and land surface models, e.g., surface temperature, radiation, and cloud cover, are also diagnosed. Applied to the CESM1.0, LIVVkit identifies a positive SMB bias that is focused largely around Greenland's southwest region that is due to insufficient ablation.

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