scholarly journals Creative computing with Landlab: an open-source toolkit for building, coupling, and exploring two-dimensional numerical models of Earth-surface dynamics

2017 ◽  
Vol 5 (1) ◽  
pp. 21-46 ◽  
Author(s):  
Daniel E. J. Hobley ◽  
Jordan M. Adams ◽  
Sai Siddhartha Nudurupati ◽  
Eric W. H. Hutton ◽  
Nicole M. Gasparini ◽  
...  
Keyword(s):  
Open Source ◽  
Numerical Models ◽  
Epistemic Uncertainty ◽  
Process Models ◽  
Third Party ◽  
Sensitivity Analyses ◽  
Surface Dynamics ◽  
New Process ◽  
Creative Computing ◽  
Classroom Use

Abstract. The ability to model surface processes and to couple them to both subsurface and atmospheric regimes has proven invaluable to research in the Earth and planetary sciences. However, creating a new model typically demands a very large investment of time, and modifying an existing model to address a new problem typically means the new work is constrained to its detriment by model adaptations for a different problem. Landlab is an open-source software framework explicitly designed to accelerate the development of new process models by providing (1) a set of tools and existing grid structures – including both regular and irregular grids – to make it faster and easier to develop new process components, or numerical implementations of physical processes; (2) a suite of stable, modular, and interoperable process components that can be combined to create an integrated model; and (3) a set of tools for data input, output, manipulation, and visualization. A set of example models built with these components is also provided. Landlab's structure makes it ideal not only for fully developed modelling applications but also for model prototyping and classroom use. Because of its modular nature, it can also act as a platform for model intercomparison and epistemic uncertainty and sensitivity analyses. Landlab exposes a standardized model interoperability interface, and is able to couple to third-party models and software. Landlab also offers tools to allow the creation of cellular automata, and allows native coupling of such models to more traditional continuous differential equation-based modules. We illustrate the principles of component coupling in Landlab using a model of landform evolution, a cellular ecohydrologic model, and a flood-wave routing model.

scholarly journals Creative computing with Landlab: an open-source toolkit for building, coupling, and exploring two-dimensional numerical models of Earth-surface dynamics

2016 ◽  
Author(s):  
Daniel E. J. Hobley ◽  
Jordan M. Adams ◽  
Sai Siddhartha Nudurupati ◽  
Eric W. H. Hutton ◽  
Nicole M. Gasparini ◽  
...  
Keyword(s):  
Open Source ◽  
Numerical Models ◽  
Epistemic Uncertainty ◽  
Process Models ◽  
Third Party ◽  
Sensitivity Analyses ◽  
Surface Dynamics ◽  
New Process ◽  
Creative Computing ◽  
Classroom Use

Abstract. The ability to model surface processes and to couple them to both subsurface and atmospheric regimes has proven invaluable to research in the Earth and planetary sciences. However, creating a new model typically demands a very large investment of time, and modifying an existing model to address a new problem typically means the new work is constrained to its detriment by model adaptations for a different problem. Landlab is an open-source software framework explicitly designed to accelerate the development of new process models by providing: (1) a set of tools and existing grid structures – including both regular and irregular grids – to make it faster and easier to develop new process components, or numerical implementations of physical processes; (2) a suite of stable, modular, and interoperable process components that can be combined to create an integrated model; and (3) a set of tools for data input, output, manipulation, and visualization. A set of example models built with these components is also provided. Landlab's structure makes it ideal not only for fully developed modelling applications, but also for model prototyping and classroom use. Because of its modular nature, it can also act as a platform for model intercomparison and epistemic uncertainty and sensitivity analyses. Landlab exposes a standardized model interoperability interface, and is able to couple to third party models and software. Landlab also offers tools to allow the creation of cellular automata, and allows native coupling of such models to more traditional continuous differential equation-based modules. We illustrate the principles of component coupling in Landlab using a model of landform evolution, a cellular ecohydrologic model, and a flood-wave routing model.

scholarly journals Intercomparison of Three Open-Source Numerical Flumes for the Surface Dynamics of Steep Focused Wave Groups

Fluids ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 9
Author(s):  
Thomas Vyzikas ◽  
Dimitris Stagonas ◽  
Christophe Maisondieu ◽  
Deborah Greaves
Keyword(s):  
Open Source ◽  
Numerical Models ◽  
Computational Cost ◽  
Experimental Results ◽  
Wave Group ◽  
Surface Dynamics ◽  
Wave Interactions ◽  
Sea State ◽  
Wave Groups ◽  
Focused Wave

NewWave-type focused wave groups are commonly used to simulate the design wave for a given sea state. These extreme wave events are challenging to reproduce numerically by the various Numerical Wave Tanks (NWTs), due to the high steepness of the wave group and the occurring wave-wave interactions. For such complex problems, the validation of NWTs against experimental results is vital for confirming the applicability of the models. Intercomparisons among different solvers are also important for selecting the most appropriate model in terms of balancing between accuracy and computational cost. The present study compares three open-source NWTs in OpenFOAM, SWASH and HOS-NWT, with experimental results for limiting breaking focused wave groups. The comparison is performed by analysing the propagation of steep wave groups and their extracted harmonics after employing an accurate focusing methodology. The scope is to investigate the capabilities of the solvers for simulating extreme NewWave-type groups, which can be used as the “design wave” for ocean and coastal engineering applications. The results demonstrate the very good performance of the numerical models and provide valuable insights to the design of the NWTs, while highlighting potential limitations in the reproduction of specific harmonics of the wave group.

scholarly journals Stormwater harvesting in ephemeral streams: how to bypass clogging and unsaturated layers

2021 ◽  
Author(s):  
José D. Henao Casas ◽  
Fritz Kalwa ◽  
Marc Walther ◽  
Randolf Rausch
Keyword(s):  
Vadose Zone ◽  
Numerical Models ◽  
Water Storage ◽  
Sensitivity Analyses ◽  
Ephemeral Streams ◽  
Infiltration Rates ◽  
Stormwater Harvesting ◽  
Harvesting Systems ◽  
Study Case ◽  
Recharge Rates

AbstractTo cope with water scarcity in drylands, stormwater is often collected in surface basins and subsequently stored in shallow aquifers via infiltration. These stormwater harvesting systems are often accompanied by high evaporation rates and hygiene problems. This is commonly a consequence of low infiltration rates, which are caused by clogging layers that form on top of the soil profile and the presence of a thick vadose zone. The present study aims to develop a conceptual solution to increase groundwater recharge rates in stormwater harvesting systems. The efficiency of vadose-zone wells and infiltration trenches is tested using analytical equations, numerical models, and sensitivity analyses. Dams built in the channel of ephemeral streams (wadis) are selected as a study case to construct the numerical simulations. The modelling demonstrated that vadose-zone wells and infiltration trenches contribute to effective bypassing of the clogging layer. By implementing these solutions, recharge begins 2250–8100% faster than via infiltration from the bed surface of the wadi reservoir. The sensitivity analysis showed that the recharge rates are especially responsive to well length and trench depth. In terms of recharge quantity, the well had the best performance; it can infiltrate up to 1642% more water than the reservoir, and between 336 and 825% more than the trench. Moreover, the well can yield the highest cumulative recharge per dollar and high recharge rates when there are limitations to the available area. The methods investigated here significantly increased recharge rates, providing practical solutions to enhance aquifer water storage in drylands.

scholarly journals A Note on the Numerical Representation of Surface Dynamics in Quasigeostrophic Turbulence: Application to the Nonlinear Eady Model

2009 ◽  
Vol 66 (4) ◽  
pp. 1063-1068 ◽  
Author(s):  
Ross Tulloch ◽  
K. Shafer Smith
Keyword(s):  
Numerical Models ◽  
Buoyancy Frequency ◽  
Complete Suppression ◽  
Numerical Representation ◽  
Vertical Resolution ◽  
Surface Dynamics ◽  
Coriolis Parameter ◽  
Theoretical Predictions ◽  
Vertical Grid ◽  
Similar Restriction

Abstract The quasigeostrophic equations consist of the advection of linearized potential vorticity coupled with advection of temperature at the bounding upper and lower surfaces. Numerical models of quasigeostrophic flow often employ greater (scaled) resolution in the horizontal than in the vertical (the two-layer model is an extreme example). In the interior, this has the effect of suppressing interactions between layers at horizontal scales that are small compared to Nδz/f (where δz is the vertical resolution, N the buoyancy frequency, and f the Coriolis parameter). The nature of the turbulent cascade in the interior is, however, not fundamentally altered because the downscale cascade of potential enstrophy in quasigeostrophic turbulence and the downscale cascade of enstrophy in two-dimensional turbulence (occurring layerwise) both yield energy spectra with slopes of −3. It is shown here that a similar restriction on the vertical resolution applies to the representation of horizontal motions at the surfaces, but the penalty for underresolving in the vertical is complete suppression of the surface temperature cascade at small scales and a corresponding artificial steepening of the surface energy spectrum. This effect is demonstrated in the nonlinear Eady model, using a finite-difference representation in comparison with a model that explicitly advects temperature at the upper and lower surfaces. Theoretical predictions for the spectrum of turbulence in the nonlinear Eady model are reviewed and compared to the simulated flows, showing that the latter model yields an accurate representation of the cascade dynamics. To accurately represent dynamics at horizontal wavenumber K in the vertically finite-differenced model, it is found that the vertical grid spacing must satisfy δz ≲ 0.3f/(NK); at wavenumbers K > 0.3f/(Nδz), the spectrum of temperature variance rolls off rapidly.

Mainlining databases

2020 ◽  
Vol 14 (4) ◽  
pp. 534-546
Author(s):  
Tianyu Li ◽  
Matthew Butrovich ◽  
Amadou Ngom ◽  
Wan Shen Lim ◽  
Wes McKinney ◽  
...  
Keyword(s):  
Open Source ◽  
Data Science ◽  
Analytical Data ◽  
Transformation Process ◽  
Third Party ◽  
Learning Tools ◽  
Network Bandwidth ◽  
External Data ◽  
Data Formats ◽  
Comparable Performance

The proliferation of modern data processing tools has given rise to open-source columnar data formats. These formats help organizations avoid repeated conversion of data to a new format for each application. However, these formats are read-only, and organizations must use a heavy-weight transformation process to load data from on-line transactional processing (OLTP) systems. As a result, DBMSs often fail to take advantage of full network bandwidth when transferring data. We aim to reduce or even eliminate this overhead by developing a storage architecture for in-memory database management systems (DBMSs) that is aware of the eventual usage of its data and emits columnar storage blocks in a universal open-source format. We introduce relaxations to common analytical data formats to efficiently update records and rely on a lightweight transformation process to convert blocks to a read-optimized layout when they are cold. We also describe how to access data from third-party analytical tools with minimal serialization overhead. We implemented our storage engine based on the Apache Arrow format and integrated it into the NoisePage DBMS to evaluate our work. Our experiments show that our approach achieves comparable performance with dedicated OLTP DBMSs while enabling orders-of-magnitude faster data exports to external data science and machine learning tools than existing methods.

Tool-Support for Software Development Processes

2010 ◽  
pp. 213-231 ◽  
Author(s):  
Marco Kuhrmann ◽  
Georg Kalus ◽  
Gerhard Chroust
Keyword(s):  
Software Development ◽  
Human Factors ◽  
Open Source ◽  
Development Process ◽  
Process Models ◽  
Tool Support ◽  
Development Projects ◽  
Crucial Step ◽  
Development Processes ◽  
The Many

Software development projects are complex. The more complex a project is, the higher are the requirements related to the software development process. The implementation of a process is a great challenge. This, in part, has to do with human factors (acceptance, etc.) as the benefits of a formal development process might not be obvious immediately and it may take a while until the process becomes the lifeblood of a team. A crucial step towards implementing, enacting and enforcing a process is to provide tool support for the many activities the process asks for. Tool support is necessary to guarantee efficiency in the project, to do the housekeeping and to minimize the “overhead” of the process. This chapter describes challenges and options for supporting process models by tools. Furthermore it describes concrete samples and shows how tool chains can be created with commercial tools as well as with open source tools.

scholarly journals Coupled Wave-2D Hydrodynamics Modeling at the Reno River Mouth (Italy) under Climate Change Scenarios

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1380 ◽  
Author(s):  
Maria Gabriella Gaeta ◽  
Davide Bonaldo ◽  
Achilleas G. Samaras ◽  
Sandro Carniel ◽  
Renata Archetti
Keyword(s):  
Climate Change ◽  
Open Source ◽  
Climate Changes ◽  
Adriatic Sea ◽  
Numerical Study ◽  
Numerical Models ◽  
Joint Probability ◽  
River Mouth ◽  
Climate Change Scenarios ◽  
Coupled Wave

This work presents the results of the numerical study implemented for the natural area of Lido di Spina, a touristic site along the Italian coast of the North Adriatic Sea, close to the mouth of River Reno. High-resolution simulations of nearshore dynamics are carried out under climate change conditions estimated for the site. The adopted modeling chain is based on the implementation of multiple-nested, open-source numerical models. More specifically, the coupled wave-2D hydrodynamics runs, using the open-source TELEMAC suite, are forced at the offshore boundary by waves resulting from the wave model (SWAN) simulations for the Adriatic Sea, and sea levels computed following a joint probability analysis approach. The system simulates present-day scenarios, as well as conditions reflecting the high IPCC greenhouse concentration trajectory named RCP8.5 under predicted climate changes. Selection of sea storms directed from SE (Sirocco events) and E–NE (Bora events) is performed together with Gumbel analysis, in order to define ordinary and extreme sea conditions. The numerical results are here presented in terms of local parameters such as wave breaking position, alongshore currents intensity and direction and flooded area, aiming to provide insights on how climate changes may impact hydrodynamics at a site scale. Although the wave energy intensity predicted for Sirocco events is expected to increase only slightly, modifications of the wave dynamics, current patterns, and inland flooding induced by climate changes are expected to be significant for extreme conditions, especially during Sirocco winds, with an increase in the maximum alongshore currents and in the inundated area compared to past conditions.

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