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Journal articles on the topic 'Nested-grid'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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1

Harris, Lucas M., and Shian-Jiann Lin. "Global-to-Regional Nested Grid Climate Simulations in the GFDL High Resolution Atmospheric Model." Journal of Climate 27, no. 13 (July 2014): 4890–910. http://dx.doi.org/10.1175/jcli-d-13-00596.1.

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A two-way nested grid version of the Geophysical Fluid Dynamics Laboratory High Resolution Atmosphere Model (HiRAM) has been developed that uses simple methods for providing nested grid boundary conditions and mass-conserving nested-to-global communication. Nested grid simulations over the Maritime Continent and over North America were performed, each at two different resolutions: a 110-km mean grid cell width refined by a factor of 3, and a 50-km mean grid cell width refined by a factor of 2. Nested grid simulations were compared against uniform-resolution simulations, and against reanalyses, to determine the effect of grid nesting on both the modeled global climate and the simulation of small-scale features. Orographically forced precipitation was robustly found to be simulated with more detail and greater realism in a nested grid simulation compared with when only the coarse grids were simulated alone. Tropical precipitation biases were reduced in the Maritime Continent region when a nested grid was introduced. Both results were robust to changes in the nested grid parameterization tunings. In North America, cold-season orographic precipitation was improved by nesting, but precipitation biases in the central and eastern United States were little changed. Improving the resolution through nesting also allowed for more intense rainfall events, greater Kelvin wave activity, and stronger tropical cyclones. Nested grid boundary artifacts were more pronounced when a one-way, noninteractive nested grid was used.

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Harris, Lucas M., and Shian-Jiann Lin. "A Two-Way Nested Global-Regional Dynamical Core on the Cubed-Sphere Grid." Monthly Weather Review 141, no. 1 (January 1, 2013): 283–306. http://dx.doi.org/10.1175/mwr-d-11-00201.1.

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Abstract A nested-grid model is constructed using the Geophysical Fluid Dynamics Laboratory finite-volume dynamical core on the cubed sphere. The use of a global grid avoids the need for externally imposed lateral boundary conditions, and the use of the same governing equations and discretization on the global and regional domains prevents inconsistencies that may arise when these differ between grids. A simple interpolated nested-grid boundary condition is used, and two-way updates use a finite-volume averaging method. Mass conservation is achieved in two-way nesting by simply not updating the mass field. Despite the simplicity of the nesting methodology, the distortion of the large-scale flow by the nested grid is such that the increase in global error norms is a factor of 2 or less in shallow-water test cases. The effect of a nested grid in the tropics on the zonal means and eddy statistics of an idealized Held–Suarez climate integration is minor, and artifacts due to the nested grid are comparable to those at the edges of the cubed-sphere grid and decrease with increasing resolution. The baroclinic wave train in a Jablonowski–Williamson test case was preserved in a nested-grid simulation while finescale features were represented with greater detail in the nested-grid region. The authors also found that lee vortices could propagate out of the nested region and onto a coarse grid, which by itself could not produce vortices. Finally, the authors discuss how concurrent integration of the nested and coarse grids can be significantly more efficient than when integrating the two grids sequentially.

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3

D'Angelo, G., T. Henning, and W. Kley. "Nested-grid calculations of disk-planet interaction." Astronomy & Astrophysics 385, no. 2 (April 2002): 647–70. http://dx.doi.org/10.1051/0004-6361:20020173.

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4

Pleim, Jonathan E., Julius S. Chang, and Kesu Zhang. "A nested grid mesoscale atmospheric chemistry model." Journal of Geophysical Research 96, no. D2 (1991): 3065. http://dx.doi.org/10.1029/90jd02026.

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5

Xu, Zhiyu, Yonghua Tan, and Xiaoming Li. "Wavelet Methods and Adaptive Grids in One-Dimensional Movable Boundary Problems." Mathematical Problems in Engineering 2020 (March 9, 2020): 1–10. http://dx.doi.org/10.1155/2020/2545292.

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Adaptive wavelet collocation methods use wavelet transform and filtering to generate adaptive grids. However, if the boundary moves, the grid becomes aberrant. It baffles wavelet transform and makes the adaptive wavelet methods lose advantages on computational efficiency. This paper develops a series of methods or skills to effectively perform wavelet transform and to generate adaptive grids for one-dimensional movable boundary problems. The methods remain the original inner grid points and keep the grid in the original-nested structure, in order to remain scanty during the whole computing process. For boundary extending, the adaptive wavelet program begins to run on the very new grid beyond the original boundary once it reaches a nested structure, which is called the Intermittent Adaptive Method as a consequence. If the boundary extends tremendously, the new nested grids can be combined to a greater nested grid for further efficiency, which is named the Grid Combine Method. While for boundary contracting, a fictitious boundary is addressed to replace the original boundary that will recede, so wavelet transform can be successfully performed on the original nested grid. Finally, two numerical tests, local features moving and gas gun, were resolved and discussed to show the evolution process of the adaptive grids with the boundaries moving. For boundary contracting, the valid points decrease because the computation domain recedes; while for boundary extending, the valid point numbers vary between a range that almost remains unchanged.

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6

Mirocha, Jeffrey D., and Katherine A. Lundquist. "Assessment of Vertical Mesh Refinement in Concurrently Nested Large-Eddy Simulations Using the Weather Research and Forecasting Model." Monthly Weather Review 145, no. 8 (August 2017): 3025–48. http://dx.doi.org/10.1175/mwr-d-16-0347.1.

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To facilitate multiscale simulation using the Weather Research and Forecasting Model, vertical mesh refinement for one-way concurrent nested simulation was recently introduced. Grid refinement in the vertical dimension removes the requirement of different grid aspect ratios on the bounding versus the nested domain, such that results from refinement are in the horizontal directions only, and thereby can also reduce numerical errors on the bounding domain arising from large aspect ratios in the presence of complex terrain. Herein, the impacts of vertical grid refinement on the evolving downstream flow in nested large-eddy simulations are evaluated in relation to other model configuration choices, including turbulence subfilter-scale (SFS) stress models, mesh configuration, and alternative methods for calculating several near-surface flow parameters. Although vertical nesting requires coarsening of the vertical grid on the bounding domain, leading to a smaller range of resolved turbulence scales in the nest’s lateral boundary conditions, parameter values within the nested domains are generally only minimally impacted, relative to nesting using the same vertical grid on each domain. Two dynamic SFS models examined herein generally improved the simulated mean wind speed, turbulence kinetic energy, stresses and spectra, on both domains, and accelerated equilibration rates within nested domains, relative to two constant coefficient models. A new method of extrapolating horizontal velocity components to near-surface locations at nested domain lateral boundaries, and a correction to the calculation of deformation elements near the surface, are each shown to slightly alter the mean parameter values, yet only minimally impact equilibration rates within the nested domain.

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7

Zhang, Y., L. Jaeglé, A. van Donkelaar, R. V. Martin, C. D. Holmes, H. M. Amos, Q. Wang, et al. "Nested-grid simulation of mercury over North America." Atmospheric Chemistry and Physics 12, no. 14 (July 16, 2012): 6095–111. http://dx.doi.org/10.5194/acp-12-6095-2012.

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Abstract. We have developed a new nested-grid mercury (Hg) simulation over North America with a 1/2° latitude by 2/3° longitude horizontal resolution employing the GEOS-Chem global chemical transport model. Emissions, chemistry, deposition, and meteorology are self-consistent between the global and nested domains. Compared to the global model (4° latitude by 5° longitude), the nested model shows improved skill at capturing the high spatial and temporal variability of Hg wet deposition over North America observed by the Mercury Deposition Network (MDN) in 2008–2009. The nested simulation resolves features such as higher deposition due to orographic precipitation, land/ocean contrast and and predicts more efficient convective rain scavenging of Hg over the southeast United States. However, the nested model overestimates Hg wet deposition over the Ohio River Valley region (ORV) by 27%. We modify anthropogenic emission speciation profiles in the US EPA National Emission Inventory (NEI) to account for the rapid in-plume reduction of reactive to elemental Hg (IPR simulation). This leads to a decrease in the model bias to −2.3% over the ORV region. Over the contiguous US, the correlation coefficient (r) between MDN observations and our IPR simulation increases from 0.60 to 0.78. The IPR nested simulation generally reproduces the seasonal cycle in surface concentrations of speciated Hg from the Atmospheric Mercury Network (AMNet) and Canadian Atmospheric Mercury Network (CAMNet). In the IPR simulation, annual mean gaseous and particulate-bound Hg(II) are within 140% and 11% of observations, respectively. In contrast, the simulation with unmodified anthropogenic Hg speciation profiles overestimates these observations by factors of 4 and 2 for gaseous and particulate-bound Hg(II), respectively. The nested model shows improved skill at capturing the horizontal variability of Hg observed over California during the ARCTAS aircraft campaign. The nested model suggests that North American anthropogenic emissions account for 10–22% of Hg wet deposition flux over the US, depending on the anthropogenic emissions speciation profile assumed. The modeled percent contribution can be as high as 60% near large point sources in ORV. Our results indicate that the North American anthropogenic contribution to dry deposition is 13–20%.

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8

Zhang, Y., L. Jaeglé, A. van Donkelaar, R. V. Martin, C. D. Holmes, H. M. Amos, Q. Wang, et al. "Nested-grid simulation of mercury over North America." Atmospheric Chemistry and Physics Discussions 12, no. 1 (January 26, 2012): 2603–46. http://dx.doi.org/10.5194/acpd-12-2603-2012.

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Abstract. We have developed a new high-resolution (1/2° latitude by 2/3° longitude) nested-grid mercury (Hg) simulation over North America employing the GEOS-Chem global chemical transport model. Emissions, chemistry, deposition, and meteorology are self-consistent between the global and nested domains. Compared to the global model (4° latitude by 5° longitude), the nested model shows improved skill at capturing the high spatial and temporal variability of Hg wet deposition over North America observed by the Mercury Deposition Network (MDN) in 2008–2009. The nested simulation resolves features such as land/ocean contrast and higher deposition due to orographic precipitation, and predicts more efficient convective rain scavenging of Hg over the southeast United States. However, the nested model overestimates Hg wet deposition over the Ohio River Valley region (ORV) by 27%. We modify anthropogenic emission speciation profiles in the US EPA National Emission Inventory (NEI) to account for the rapid in-plume reduction of reactive to elemental Hg (IPR simulation). This leads to a decrease in the model bias to +3% over the ORV region. Over the contiguous US, the correlation coefficient (r) between MDN observations and our IPR simulation increases from 0.63 to 0.78. The IPR nested simulation generally reproduces the seasonal cycle in surface concentrations of speciated Hg from the Atmospheric Mercury Network (AMNet) and Canadian Atmospheric Mercury Network (CAMNet). In the IPR simulation, annual mean reactive gaseous and particulate-bound Hg are within 80% and 10% of observations, respectively. In contrast, the simulation with unmodified anthropogenic Hg speciation profiles overestimates these observations by factors of 2 to 4. The nested model shows improved skill at capturing the horizontal variability of Hg observed over California during the ARCTAS aircraft campaign. We find that North American anthropogenic emissions account for 10–22% of Hg wet deposition flux over the US, depending on the anthropogenic emissions speciation profile assumed. The percent contribution can be as high as 60% near large point emission sources in ORV. The contribution for the dry deposition is 13–20%.

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9

Wang, Qi Sheng, and Xue Ling Wang. "Convergence Analysis and the Nested Refinement for the Trapezoid Finite Element." Advanced Materials Research 317-319 (August 2011): 1921–25. http://dx.doi.org/10.4028/www.scientific.net/amr.317-319.1921.

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In this paper, a class of the new method of nested refinement based on self-adaption grid is discussed. The level trapezoid grid nested refinement on the plan domain and some related properties are investigated, and the convergence results are obtained for the second order self-adjoint elliptic problem on the trapezoid finite element.

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10

Ziegler, Udo, and Harold W. Yorke. "A nested grid refinement technique for magnetohydrodynamical flows." Computer Physics Communications 101, no. 1-2 (April 1997): 54–74. http://dx.doi.org/10.1016/s0010-4655(96)00163-4.

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11

Chen, D., Y. Wang, M. B. McElroy, K. He, R. M. Yantosca, and P. Le Sager. "Regional CO pollution and export in China simulated by the high-resolution nested-grid GEOS-Chem model." Atmospheric Chemistry and Physics 9, no. 11 (June 12, 2009): 3825–39. http://dx.doi.org/10.5194/acp-9-3825-2009.

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Abstract. An updated version of the nested-grid GEOS-Chem model is developed allowing for higher horizontal (0.5°×0.667°) resolution as compared to global models. CO transport over a heavily polluted region, the Beijing-Tianjin-Hebei (BTH) city cluster in China, and the pattern of outflow from East China in summertime are investigated. Comparison of the nested-grid with global models indicates that the fine-resolution nested-grid model is capable of resolving individual cities with high associated emission intensities. The nested-grid model indicates the presence of a high CO column density over the Sichuan Basin in summer, attributable to the low-level stationary vortex associated with the Basin's topographical features. The nested-grid model provides good agreement also with measurements from a suburban monitoring site in Beijing during summer 2005. Tagged CO simulation results suggest that regional emissions make significant contributions to elevated CO levels over Beijing on polluted days and that the southeastward moving cyclones bringing northwest winds to Beijing are the key meteorological mechanisms responsible for dispersion of pollution over Beijing in summer. Overall CO fluxes to the NW Pacific from Asia are found to decrease by a factor of 3–4 from spring to summer. Much of the seasonal change is driven by decreasing fluxes from India and Southeast Asia in summer, while fluxes from East China are only 30% lower in summer than in spring. Compared to spring, summertime outflow from Chinese source regions is strongest at higher latitudes (north of 35° N). The deeper convection in summer transporting CO to higher altitudes where export is more efficient is largely responsible for enhanced export in summer.

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12

Chen, D., Y. Wang, M. B. McElroy, K. He, R. M. Yantosca, and P. Le Sager. "Regional CO pollution in China simulated by the high-resolution nested-grid GEOS-Chem model." Atmospheric Chemistry and Physics Discussions 9, no. 2 (March 4, 2009): 5853–87. http://dx.doi.org/10.5194/acpd-9-5853-2009.

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Abstract. An updated version of the nested-grid GEOS-Chem model is developed allowing for higher horizontal (0.5°×0.667°) and vertical resolution as compared to global models. CO transport over a heavily polluted region, the Beijing-Tianjin-Hebei (BTH) city cluster in China, and the pattern of outflow from East China in summertime are investigated. Comparison of the nested-grid with global models indicates that the fine-resolution nested-grid model is capable of resolving individual cities with high associated emission intensities. The nested-grid model indicates the presence of a high CO column density over the Sichuan Basin in summer, attributable to the low-level stationary vortex associated with the Basin's topographical features. The nested-grid model provides good agreement also with measurements from a suburban monitoring site in Beijing during summer 2005. Tagged CO simulation results suggest that regional emissions make significant contributions to elevated CO levels over Beijing on polluted days and that the southeastward moving cyclones bringing northwest winds to Beijing are the key meteorological mechanisms responsible for dispersion of pollution over Beijing in summer. Overall CO fluxes to the NW Pacific from Asia are found to decrease by a factor of 3–4 from spring to summer. Much of the seasonal change is driven by decreasing fluxes from India and Southeast Asia in summer, while fluxes from East China are only 30% lower in summer than in spring. Compared to spring, summertime outflow from Chinese source regions is strongest at higher latitudes (north of 35° N). The deeper convection in summer transporting CO to higher altitudes where export is more efficient is largely responsible for enhanced export in summer.

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13

Wilson, Kenneth R., and David R. Anderson. "Evaluation of a Nested Grid Approach for Estimating Density." Journal of Wildlife Management 49, no. 3 (July 1985): 675. http://dx.doi.org/10.2307/3801693.

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14

Kirk, B., K. Lipnikov, and G. F. Carey. "Nested Grid Iteration for Incompressible Viscous Flow and Transport." International Journal of Computational Fluid Dynamics 17, no. 4 (August 2003): 253–62. http://dx.doi.org/10.1080/1061856031000173635.

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15

Peggion, Germana. "Numerical inaccuracies across the interface of a nested grid." Numerical Methods for Partial Differential Equations 10, no. 4 (July 1994): 455–73. http://dx.doi.org/10.1002/num.1690100405.

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16

Peng, Yih-Ferng, Rajat Mittal, Amalendu Sau, and Robert R. Hwang. "Nested Cartesian grid method in incompressible viscous fluid flow." Journal of Computational Physics 229, no. 19 (September 2010): 7072–101. http://dx.doi.org/10.1016/j.jcp.2010.05.041.

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17

Deleersnijder, Eric, and Pierre F. J. Lermusiaux. "Multi-scale modeling: nested-grid and unstructured-mesh approaches." Ocean Dynamics 58, no. 5-6 (November 27, 2008): 335–36. http://dx.doi.org/10.1007/s10236-008-0170-5.

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18

Wang, Qi Sheng, and Yi Gao Zhao. "Convergence Analysis for the Nested Refinement of Triangular Finite Element." Advanced Materials Research 317-319 (August 2011): 1926–30. http://dx.doi.org/10.4028/www.scientific.net/amr.317-319.1926.

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In this paper, the method of the nested refinement for triangular mesh and some relevant conclusions are considered. The Κ level triangular grid nested refinement on the plan domain Ω and some related properties are discussed , and the convergence results are obtained for the first boundary value problem of Poisson equation under the nested refinement of triangular finite element.

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19

Villa, G., S. Mas, X. Fernández-Villarino, J. Martínez-Luceño, J. C. Ojeda, B. Pérez-Martín, J. A. Tejeiro, C. García-González, E. López-Romero, and C. Soteres. "THE NEED OF NESTED GRIDS FOR AERIAL AND SATELLITE IMAGES AND DIGITAL ELEVATION MODELS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B2 (June 7, 2016): 131–38. http://dx.doi.org/10.5194/isprsarchives-xli-b2-131-2016.

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Usual workflows for production, archiving, dissemination and use of Earth observation images (both aerial and from remote sensing satellites) pose big interoperability problems, as for example: non-alignment of pixels at the different levels of the pyramids that makes it impossible to overlay, compare and mosaic different orthoimages, without resampling them and the need to apply multiple resamplings and compression-decompression cycles. These problems cause great inefficiencies in production, dissemination through web services and processing in “Big Data” environments. Most of them can be avoided, or at least greatly reduced, with the use of a common “nested grid” for mutiresolution production, archiving, dissemination and exploitation of orthoimagery, digital elevation models and other raster data. “Nested grids” are space allocation schemas that organize image footprints, pixel sizes and pixel positions at all pyramid levels, in order to achieve coherent and consistent multiresolution coverage of a whole working area. A “nested grid” must be complemented by an appropriate “tiling schema”, ideally based on the “quad-tree” concept. In the last years a “de facto standard” grid and Tiling Schema has emerged and has been adopted by virtually all major geospatial data providers. It has also been adopted by OGC in its “WMTS Simple Profile” standard. In this paper we explain how the adequate use of this tiling schema as common nested grid for orthoimagery, DEMs and other types of raster data constitutes the most practical solution to most of the interoperability problems of these types of data.

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Villa, G., S. Mas, X. Fernández-Villarino, J. Martínez-Luceño, J. C. Ojeda, B. Pérez-Martín, J. A. Tejeiro, C. García-González, E. López-Romero, and C. Soteres. "THE NEED OF NESTED GRIDS FOR AERIAL AND SATELLITE IMAGES AND DIGITAL ELEVATION MODELS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B2 (June 7, 2016): 131–38. http://dx.doi.org/10.5194/isprs-archives-xli-b2-131-2016.

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Usual workflows for production, archiving, dissemination and use of Earth observation images (both aerial and from remote sensing satellites) pose big interoperability problems, as for example: non-alignment of pixels at the different levels of the pyramids that makes it impossible to overlay, compare and mosaic different orthoimages, without resampling them and the need to apply multiple resamplings and compression-decompression cycles. These problems cause great inefficiencies in production, dissemination through web services and processing in “Big Data” environments. Most of them can be avoided, or at least greatly reduced, with the use of a common “nested grid” for mutiresolution production, archiving, dissemination and exploitation of orthoimagery, digital elevation models and other raster data. “Nested grids” are space allocation schemas that organize image footprints, pixel sizes and pixel positions at all pyramid levels, in order to achieve coherent and consistent multiresolution coverage of a whole working area. A “nested grid” must be complemented by an appropriate “tiling schema”, ideally based on the “quad-tree” concept. In the last years a “de facto standard” grid and Tiling Schema has emerged and has been adopted by virtually all major geospatial data providers. It has also been adopted by OGC in its “WMTS Simple Profile” standard. In this paper we explain how the adequate use of this tiling schema as common nested grid for orthoimagery, DEMs and other types of raster data constitutes the most practical solution to most of the interoperability problems of these types of data.

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21

Harris, Lucas M., and Dale R. Durran. "An Idealized Comparison of One-Way and Two-Way Grid Nesting." Monthly Weather Review 138, no. 6 (June 1, 2010): 2174–87. http://dx.doi.org/10.1175/2010mwr3080.1.

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Abstract Most mesoscale models can be run with either one-way (parasitic) or two-way (interactive) grid nesting. This paper presents results from a linear 1D shallow-water model to determine whether the choice of nesting method can have a significant impact on the solution. Two-way nesting was found to be generally superior to one-way nesting. The only situation in which one-way nesting performs better than two-way is when very poorly resolved waves strike the nest boundary. A simple filter is proposed for use exclusively on the coarse-grid values within the sponge zone of an otherwise conventional sponge boundary condition (BC). The two-way filtered sponge BC gives better results than any of the other methods considered in these tests. Results for all wavelengths were found to be robust to other changes in the formulation of the sponge boundary, particularly with the width of the sponge layer. The increased reflection for longer-wavelength disturbances in the one-way case is due to a phase difference between the coarse- and nested-grid solutions at the nested-grid boundary that accumulates because of the difference in numerical phase speeds between the grids. Reflections for two-way nesting may be estimated from the difference in numerical group velocities between the coarse and nested grids, which only becomes large for waves that are poorly resolved on the coarse grid.

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22

Cui, Weizhe, and Qichen Hao. "Comparing Q-Tree with Nested Grids for Simulating Managed River Recharge of Groundwater." Water 12, no. 12 (December 14, 2020): 3516. http://dx.doi.org/10.3390/w12123516.

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The use of rivers to recharge groundwater is a key water resource management method. High-precision simulations of the groundwater level near rivers can be used to accurately assess the recharge effect. In this study, we used two unstructured grid refinement methods, namely, the quadtree (Q-tree) and nested grid refinement techniques, to simulate groundwater movement under river recharge. We comparatively analyzed the two refinement methods by considering the simulated groundwater level changes before and after the recharge at different distances from the river and by analyzing the groundwater flow and model computation efficiency. Compared to the unrefined model, the two unstructured grid refinement models significantly improve the simulation precision and more accurately describe groundwater level changes from river recharge. The unstructured grid refinement models have higher calculation efficiencies than the base model (the global refinement model) without compromising the simulation precision too much. The Q-tree model has a higher simulation precision and a lower computation time than the nested grid model. In summary, the Q-tree grid refinement method increases the computation efficiency while guaranteeing simulation precision at a certain extent. We therefore recommended the use of this grid refinement method in simulating river recharge to the aquifers.

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Zhou, Chenglong, and Ming Chen. "Aerodynamic Simulation of Helicopter Based on Polyhedron Nested Grid Technology." Applied Sciences 10, no. 22 (November 23, 2020): 8304. http://dx.doi.org/10.3390/app10228304.

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In this paper, a computational fluid dynamics (CFD) simulation method based on the polyhedral nested grid is developed. By comparing the simulation and test results of the hovering flow field of the Caradonna–Tung rotor, the forward flight flow field of the AH-1G rotor, the interference flow field of the Robin rotor/fuselage, and the hovering and forward flight flow field of a coaxial rotor, it is proven that the method proposed in this paper can achieve high calculation accuracy under various working conditions. The dual time-stepping method is used for the transient simulation, and the Spalart–Allmaras (S-A) turbulence model, which is widely used in aviation, is adopted in the simulation.

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Machida, M. N., K. Tomisaka, and T. Matsumoto. "Binary Star Formation and Mass Outflows: MHD Nested Grid Simulation." International Astronomical Union Colloquium 191 (August 2004): 168–72. http://dx.doi.org/10.1017/s025292110000871x.

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AbstractWe study the binary star formation process from a rotating magnetized molecular cloud. We assume an isothermal cylindrical cloud in hydrostatic balance whose rotation axis and the direction of global magnetic field lines are both identical, and parallel to the cylinder axis. We added axisymmetric and non-axisymmetric density perturbations to the initial state and followed the subsequent evolutions. The evolution is characterized by three parameters: the amplitude of the non-axisymmetric perturbations, the rotation speed, and the magnetic field strength. As a result, it is found that non-axisymmetry hardly evolves in the early phase, but begins to grow after the gas contracts and forms a thin disk. There are two types of fragmentation: fragmentation from a ring and that from a bar. Thin adiabatic cores fragments if a thickness is smaller than 1/4 of the radius. For the fragments to survive, they should be formed in a heavily elongated barred core or a flat round disk. In the models showing fragmentation, outflows from respective fragments are found as well as those driven by the rotating bar or the disk.

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LAUGIER, MARC, PHILIPPE ANGOT, and LAURENT MORTIER. "NESTED GRID METHODS FOR AN OCEAN MODEL: A COMPARATIVE STUDY." International Journal for Numerical Methods in Fluids 23, no. 11 (December 15, 1996): 1163–95. http://dx.doi.org/10.1002/(sici)1097-0363(19961215)23:11<1163::aid-fld462>3.0.co;2-i.

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26

Wackers, Jeroen. "A nested-grid direct Poisson solver for concentrated source terms." Journal of Computational and Applied Mathematics 180, no. 1 (August 2005): 1–12. http://dx.doi.org/10.1016/j.cam.2004.09.054.

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27

Zodiatis, G., R. Lardner, A. Lascaratos, G. Georgiou, G. Korres, and M. Syrimis. "High resolution nested model for the Cyprus, NE Levantine Basin, eastern Mediterranean Sea: implementation and climatological runs." Annales Geophysicae 21, no. 1 (January 31, 2003): 221–36. http://dx.doi.org/10.5194/angeo-21-221-2003.

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Abstract. A high resolution nested flow model for the coastal, shelf and open sea areas of the Cyprus Basin, NE Levantine, eastern Mediterranean Sea is implemented to fulfil the objectives of the Mediterranean Forecasting System Pilot Project, funded by the EU. The Cyprus coastal ocean model is nested entirely within a coarse regional grid model of the eastern Mediterranean Sea, using the MODB climatology for initialisation and the ECMWF perpetual year surface forcing. The nested simulations of the Cyprus model were able to reproduce, with greater detail, flow features similar to those of the coarse grid regional model. The project results show the feasibility of the approach for the development of an operational forecasting system in the Mediterranean Sea, particularly in the Cyprus coastal/shelf sea area. Key words. Oceanography: general (descriptive and regional oceanography; numerical modelling) Oceanography: physical (general circulation)

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Wang, Qi Sheng, and Yi Gao Zhao. "Convergence Analysis for the Elliptic Boundary Value Problem of Rectangle Nested Refinement Finite Element with Q₁ Truncation." Applied Mechanics and Materials 182-183 (June 2012): 1567–70. http://dx.doi.org/10.4028/www.scientific.net/amm.182-183.1567.

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In this paper, the finite element method of rectangle nested refinement was introduced, and the level Κ rectangle grid refinement and related properties on planar region were given. According to boundary problems of a kind of elliptic equation, the results of the convergence were proved for the finite element of Κ level rectangle nested refinement under Q1mappings by affine mappings replaced.

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Bonnardot, V., and S. Cautenet. "Mesoscale Atmospheric Modeling Using a High Horizontal Grid Resolution over a Complex Coastal Terrain and a Wine Region of South Africa." Journal of Applied Meteorology and Climatology 48, no. 2 (February 1, 2009): 330–48. http://dx.doi.org/10.1175/2008jamc1710.1.

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Abstract The Regional Atmospheric Modeling System (RAMS) was used to assess local air circulation patterns over the wine-producing Stellenbosch region of South Africa. Numerical simulations using four nested grids (25, 5, and 1 km, and 200 m of horizontal resolution) were performed for each day of February 2000 (during the grape-ripening period) over southern Western Cape Province. Modeled hourly data were extracted from the analysis files and used to produce mean hourly fields (temperature, relative humidity, wind speed, and radiation). Three runs with increasing horizontal resolutions for the finer grid were performed (run 1 with two nested grids of 25 and 5 km; run 2 with three nested grids of 25, 5, and 1 km; run 3 with four nested grids of 25, 5, and 1 km, and 200 m). For each event, the simulations of 1-km and 200-m resolution were superior to the 5-km-resolution simulation, especially in reproducing the local air circulations (sea and slopes breezes) because of a better representation of the local terrain (topography and vegetation cover). The use of a high-resolution grid (200 m) may be of greater value in the identification of potential terrain for viticulture.

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Huebener, H., K. Born, and M. Kerschgens. "Downscaling heavy rainfall in the subtropics – a simple approach for dynamical nesting." Advances in Geosciences 10 (April 26, 2007): 9–16. http://dx.doi.org/10.5194/adgeo-10-9-2007.

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Abstract. The simulation of local scale precipitation with nested models often suffers from large errors in the boundary rows. Advection of precipitation into the model domain of the small scale model can lead to an overestimation of precipitation in the boundary grid cells of the nested model and a drying of the interior grid area. Consequently, the finer scale structure of rainfall events of the small scale model can not evolve. These errors result from three main sources: "dynamical", "scale", and "parameterization" problems. As a first step to reduce the "parameterization" boundary errors, we propose a nesting procedure where rainwater from the driving larger scale model is converted to cloud water in the smaller scale model. The nesting method is applied to a case study of heavy rainfall in semi-arid southern Morocco. The results show the elimination of erroneous excessive rainfall in the boundary rows and slightly enhanced rainfall in the interior of the nested model domain. Additionally, fine scale structures in the precipitation patterns develop. The excessive surface runoff is clearly diminished in comparison to the standard nesting procedure. The proposed approach enables scale consistent precipitation patterns resulting from model physics and grid-resolution of the smaller scale model for the complete model domain.

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31

Jett, D. A., and J. D. Nichols. "A Field Comparison of Nested Grid and Trapping Web Density Estimators." Journal of Mammalogy 68, no. 4 (November 27, 1987): 888–92. http://dx.doi.org/10.2307/1381576.

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32

Pastoll, Hugh, Lukas Solanka, Mark C. W. van Rossum, and Matthew F. Nolan. "Feedback Inhibition Enables Theta-Nested Gamma Oscillations and Grid Firing Fields." Neuron 77, no. 1 (January 2013): 141–54. http://dx.doi.org/10.1016/j.neuron.2012.11.032.

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33

Hutchinson, Todd A. "An Analysis of NMC's Nested Grid Model Forecasts of Alberta Clippers." Weather and Forecasting 10, no. 3 (September 1995): 632–41. http://dx.doi.org/10.1175/1520-0434(1995)010<0632:aaonng>2.0.co;2.

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34

Alapaty, Kiran, Rohit Mathur, and Talat Odman. "Intercomparison of Spatial Interpolation Schemes for Use in Nested Grid Models." Monthly Weather Review 126, no. 1 (January 1998): 243–49. http://dx.doi.org/10.1175/1520-0493(1998)126<0243:iosisf>2.0.co;2.

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35

Jiang, Hong, Wen‐Gen Tang, and Shuai‐Xuan Pang. "Off‐grid DOA estimation for nested array using atomic norm minimisation." Electronics Letters 54, no. 23 (November 2018): 1344–46. http://dx.doi.org/10.1049/el.2018.6532.

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36

Houghton, David D., Ralph A. Petersen, and Richard L. Wobus. "Spatial Resolution Impacts on National Meteorological Center Nested Grid Model Simulations." Monthly Weather Review 121, no. 5 (May 1993): 1450–66. http://dx.doi.org/10.1175/1520-0493(1993)121<1450:srionm>2.0.co;2.

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37

Mueck, T. A., and M. J. Schauer. "Optimizing sort order query execution in balanced and nested grid files." IEEE Transactions on Knowledge and Data Engineering 7, no. 2 (April 1995): 246–60. http://dx.doi.org/10.1109/69.382295.

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38

Hashimoto, Atsushi, James M. Done, Laura D. Fowler, and Cindy L. Bruyère. "Tropical cyclone activity in nested regional and global grid-refined simulations." Climate Dynamics 47, no. 1-2 (October 5, 2015): 497–508. http://dx.doi.org/10.1007/s00382-015-2852-2.

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39

Li, Dan, Jinjun Ji, and Yinpeng Li. "Climate simulations based on a different-grid nested and coupled model." Advances in Atmospheric Sciences 19, no. 3 (May 2002): 487–99. http://dx.doi.org/10.1007/s00376-002-0081-1.

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Suzuki, Hitoshi, Akira Ishiguro, and Takao Nishizeki. "Edge-disjoint paths in a grid bounded by two nested rectangles." Discrete Applied Mathematics 27, no. 1-2 (May 1990): 157–78. http://dx.doi.org/10.1016/0166-218x(90)90136-z.

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41

Chen, Fangfang, Jisheng Dai, Nan Hu, and Zhongfu Ye. "Sparse Bayesian learning for off-grid DOA estimation with nested arrays." Digital Signal Processing 82 (November 2018): 187–93. http://dx.doi.org/10.1016/j.dsp.2018.08.004.

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42

Daniels, Megan H., Katherine A. Lundquist, Jeffrey D. Mirocha, David J. Wiersema, and Fotini K. Chow. "A New Vertical Grid Nesting Capability in the Weather Research and Forecasting (WRF) Model." Monthly Weather Review 144, no. 10 (October 2016): 3725–47. http://dx.doi.org/10.1175/mwr-d-16-0049.1.

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Mesoscale atmospheric models are increasingly used for high-resolution (<3 km) simulations to better resolve smaller-scale flow details. Increased resolution is achieved using mesh refinement via grid nesting, a procedure where multiple computational domains are integrated either concurrently or in series. A constraint in the concurrent nesting framework offered by the Weather Research and Forecasting (WRF) Model is that mesh refinement is restricted to the horizontal dimensions. This limitation prevents control of the grid aspect ratio, leading to numerical errors due to poor grid quality and preventing grid optimization. Herein, a procedure permitting vertical nesting for one-way concurrent simulation is developed and validated through idealized cases. The benefits of vertical nesting are demonstrated using both mesoscale and large-eddy simulations (LES). Mesoscale simulations of the Terrain-Induced Rotor Experiment (T-REX) show that vertical grid nesting can alleviate numerical errors due to large aspect ratios on coarse grids, while allowing for higher vertical resolution on fine grids. Furthermore, the coarsening of the parent domain does not result in a significant loss of accuracy on the nested domain. LES of neutral boundary layer flow shows that, by permitting optimal grid aspect ratios on both parent and nested domains, use of vertical nesting yields improved agreement with the theoretical logarithmic velocity profile on both domains. Vertical grid nesting in WRF opens the path forward for multiscale simulations, allowing more accurate simulations spanning a wider range of scales than previously possible.

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Tsanis, Ioannis K., and Jian Wu. "A Nested-Grid Hydrodynamic/Pollutant Transport Model for Nearshore Areas in Hamilton Harbour." Water Quality Research Journal 30, no. 2 (May 1, 1995): 205–30. http://dx.doi.org/10.2166/wqrj.1995.022.

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Abstract A nested-grid depth-averaged circulation model was developed and applied to three nearshore areas in Hamilton Harbour: the western basin, LaSalle Park waterfront and the northeastern shoreline. The grid sizes used were 100 m for the whole harbour, and 25 m for the three nearshore areas. General features of current circulation and horizontal mixing times under various wind directions and speeds were obtained for the whole harbour using the coarse-grid model. The fine-grid model (water elevations and current information on the open boundaries were obtained from the whole harbour model) then provided current patterns which were used to drive the pollutant transport model. Simulation results reveal that the current in the fine-grid model is close to the current from the coarse-grid model, while more detailed current structures are explored. The water elevations from the fine-grid model agree well with the elevations from the coarse-grid one. The impact of artificial islands was examined by studying changes in current patterns, pollutant peaks, exposure and flushing time in different locations of concern. The design proposed provides: (i) minimum change in the existing current patterns; (ii) avoidance of pollutant hot spots; and (iii) minimum changes in the flushing time of pollutants.

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Chen, Yongping, Shunqi Pan, Judith Wolf, and Yanliang Du. "DOWNSCALING EFFECTS ON MODELLING WAVES, TIDES AND STORM SURGE." Coastal Engineering Proceedings 1, no. 32 (February 1, 2011): 33. http://dx.doi.org/10.9753/icce.v32.waves.33.

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This paper presents the results of downscaling effects when modelling waves, tides and storm surge using a nested modelling system. In this study, the coupled POLCOMS/ProWAM models are used, with 3 nested computational domains, the largest of which covers part of north-eastern Atlantic Ocean with a coarse resolution grid and the smallest covers the surrounding waters of south-west Cornish coast of the UK with a finer resolution grid. Applying the identical surface wind forcing to all 3 computational domains and the wave and tide boundary conditions provided from the coarse to finer domains, the computed wave heights, tides and surge levels are examined at selected locations to study the downscaling effects. The results show that downscaling could considerably increase accuracy of model predictions in the local domain. For the particular test conditions used in the present study, 3-level and 2-level downscaling produces similar results in the local domain. The results also indicate that downscaling with reduction of grid resolution by 6 times is acceptable for the study site.

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Tan, Zeli, Qianlai Zhuang, Daven K. Henze, Christian Frankenberg, Ed Dlugokencky, Colm Sweeney, Alexander J. Turner, Motoki Sasakawa, and Toshinobu Machida. "Inverse modeling of pan-Arctic methane emissions at high spatial resolution: what can we learn from assimilating satellite retrievals and using different process-based wetland and lake biogeochemical models?" Atmospheric Chemistry and Physics 16, no. 19 (October 12, 2016): 12649–66. http://dx.doi.org/10.5194/acp-16-12649-2016.

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Abstract. Understanding methane emissions from the Arctic, a fast-warming carbon reservoir, is important for projecting future changes in the global methane cycle. Here we optimized methane emissions from north of 60° N (pan-Arctic) regions using a nested-grid high-resolution inverse model that assimilates both high-precision surface measurements and column-average SCanning Imaging Absorption spectroMeter for Atmospheric CHartogrphY (SCIAMACHY) satellite retrievals of methane mole fraction. For the first time, methane emissions from lakes were integrated into an atmospheric transport and inversion estimate, together with prior wetland emissions estimated with six biogeochemical models. In our estimates, in 2005, global methane emissions were in the range of 496.4–511.5 Tg yr−1, and pan-Arctic methane emissions were in the range of 11.9–28.5 Tg yr−1. Methane emissions from pan-Arctic wetlands and lakes were 5.5–14.2 and 2.4–14.2 Tg yr−1, respectively. Methane emissions from Siberian wetlands and lakes are the largest and also have the largest uncertainty. Our results indicate that the uncertainty introduced by different wetland models could be much larger than the uncertainty of each inversion. We also show that assimilating satellite retrievals can reduce the uncertainty of the nested-grid inversions. The significance of lake emissions cannot be identified across the pan-Arctic by high-resolution inversions, but it is possible to identify high lake emissions from some specific regions. In contrast to global inversions, high-resolution nested-grid inversions perform better in estimating near-surface methane concentrations.

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Li, Jianfeng, Xiong Xu, Ping Li, and Qiting Zhang. "Partial Dictionary Based Off-Grid DOA Estimation Using Combined Coprime and Nested Array." Wireless Communications and Mobile Computing 2021 (May 27, 2021): 1–8. http://dx.doi.org/10.1155/2021/9939651.

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A partial dictionary based direction of arrival (DOA) estimation method which addresses the off-grid problem and exploits combined coprime and nested array (CCNA) is proposed. Compared to general coprime array, CCNA yields two sparse coprime subarrays in the coarray domain by adding a third subarray in the physical-array domain. To ensure the DOA estimation performance, the subarray with larger aperture is chosen, and the cyclic phase ambiguity caused by the sparse subarray allows partial dictionary covering arbitrary cycle to represent the whole atoms, and then, the off-grid sparse reconstruction method is developed to amend the grid mismatch. After the sparse recovery and off-grid compensation, ambiguous DOA estimations can be eliminated by substituting the estimations into the whole virtual array. Multiple simulations verify that the proposed algorithm outperforms the other state-of-the-art methods in terms of DOA estimation accuracy and angular resolution.

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47

Warner, Thomas T., and Hsiao-Ming Hsu. "Nested-Model Simulation of Moist Convection: The Impact of Coarse-Grid Parameterized Convection on Fine-Grid Resolved Convection." Monthly Weather Review 128, no. 7 (July 2000): 2211–31. http://dx.doi.org/10.1175/1520-0493(2000)128<2211:nmsomc>2.0.co;2.

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Li, Jianfeng, and Xiaofei Zhang. "Two-dimensional grid-less angle estimation based on three parallel nested arrays." Signal Processing 173 (August 2020): 107577. http://dx.doi.org/10.1016/j.sigpro.2020.107577.

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49

Wang, Yuxuan X., Michael B. McElroy, Daniel J. Jacob, and Robert M. Yantosca. "A nested grid formulation for chemical transport over Asia: Applications to CO." Journal of Geophysical Research: Atmospheres 109, no. D22 (November 24, 2004): n/a. http://dx.doi.org/10.1029/2004jd005237.

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Matsumoto, Tomoaki, and Tomoyuki Hanawa. "A Fast Algorithm for Solving the Poisson Equation on a Nested Grid." Astrophysical Journal 583, no. 1 (January 20, 2003): 296–307. http://dx.doi.org/10.1086/345338.

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