Article
Mechanics
Ryosuke Kurashina, Pavel Berloff, Igor Shevchenko
Summary: This study examines the influence of flow nonlinearity in western boundary layers on wind-driven ocean gyres. Nonlinear effects are found to play a crucial role in shaping the circulation patterns, particularly in balancing potential vorticity between gyres downstream. Furthermore, Lagrangian particle analysis reveals inter-gyre exchange mechanisms that weaken the eastward jet extension.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Multidisciplinary Sciences
Benjamin A. Storer, Michele Buzzicotti, Hemant Khatri, Stephen M. Griffies, Hussein Aluie
Summary: The development of satellite altimetry has led to increased attention on the presence of mesoscale eddies in the ocean. This study introduces a new method to analyze larger scales and reveals the Antarctic Circumpolar Current as the dominant feature of the global circulation. The study also shows seasonal variations in length scales, with different kinetic energy peaks in spring and late summer in both hemispheres.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Dhruv Balwada, Jin-Han Xie, Raffaele Marino, Fabio Feraco
Summary: The ocean's turbulent energy cycle has a paradox of kinetic energy transferring between large and small scales, with the first observation of a dual kinetic energy cascade indicating a seasonal modulation in energy transfer.
Article
Astronomy & Astrophysics
Fabio Cruz, Thomas Grismayer, Luis O. Silva
Summary: Electron-positron pair cascades in extreme electromagnetic fields of neutron star polar caps are a key source of magnetospheric plasma. A simplified model is used to analytically and numerically study these cascades, showing that large-amplitude electric field oscillations are inductively driven by the resulting plasma. Plasma instabilities arising in these oscillations lead to accelerated particles driving secondary pair bursts that dampen the large-amplitude oscillations. An analytical model describing the interplay between pair production and kinetic collective plasma processes is proposed, with results in excellent agreement with particle-in-cell simulations.
ASTROPHYSICAL JOURNAL
(2021)
Article
Environmental Sciences
Seyed Mohammadreza Mahdavian, Mahmoud Ahmadpour Borazjani, Hamid Mohammadi, Mohammad Reza Asgharipour, Hamed Najafi Alamdarlo
Summary: Iran's agricultural production has expanded in recent years, but environmental issues such as pollution, depletion of resources, and erosion have been neglected. This study investigates the relationship between energy consumption, fertilizer consumption, CO2 emissions, temperature changes, and production using statistical methods. The results show that energy consumption has both positive and negative effects on production, while fertilizer use and CO2 emissions have positive effects. Temperature changes have both increasing and reducing effects on production. The findings suggest the need for reforming energy prices, investing in mechanized agriculture, shifting to renewable energy, and promoting green growth.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Article
Engineering, Mechanical
Meng Li, Xingjian Jing
Summary: A novel Volterra series-based frequency domain method is proposed in this study for nonlinear energy harvesting systems. The lnCOS method is introduced to achieve parametric characteristic expression for the nonlinear output frequency response and power generation function. Compared with traditional methods, this approach provides a more direct computation process and establishes a connection between power outputs and critical system parameters.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2022)
Article
Engineering, Mechanical
Yun-Peng Zhu, Z. Q. Lang, Yu-Zhu Guo
Summary: This study introduces a new method called nonlinear model standardization, which transforms the model of a nonlinear system into a form that can be studied over the whole stable regime about an equilibrium in order to facilitate the use of Volterra series approach. By applying this method to three case studies, it demonstrates the significance of this approach in engineering practices.
NONLINEAR DYNAMICS
(2021)
Article
Engineering, Civil
In-Chul Kim, James M. Kaihatu
Summary: A new nonlinear frequency-domain model based on the mild-slope equation has been outlined, showing an enhanced correspondence between nonlinearity scaling and bathymetry variation compared to previous models. By using an elliptic model and a parabolic approximation, the model efficiently simulates the equations and exhibits improved performance based on comparisons with experimental data and previously-formulated models.
COASTAL ENGINEERING
(2021)
Article
Oceanography
Guidi Zhou, Xuhua Cheng
Summary: This paper evaluates the importance of residual kinetic energy (RKE) in ocean energetics, proposing methods for its assessment and handling, including Reynolds decomposition and spectral truncation. Through practical ocean observations, variations in MREE under different conditions were identified, highlighting the necessity of estimating MREE before analyzing energy budgets.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2021)
Article
Engineering, Electrical & Electronic
Feng Wang, Ying Sun, Qiang Chen, Jingjing Xing, Yihua Xia, Yixin Zhang, Xuping Zhang
Summary: In this paper, a method is proposed to correct the nonlinear frequency sweep in optical frequency domain reflectometry (OFDR) by introducing an acousto-optic modulator as the frequency shifter. Experimental results demonstrate that this method can improve the spatial resolutions and robustness for different correction methods, showing a wide-range effect in the promotion of OFDR technique.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Geochemistry & Geophysics
Xiao Chen, Zhaoyun Zong, Yaming Yang, Yongjian Zeng
Summary: Viscoelastic theory-based frequency-dependent amplitude variation with offset (AVO) inversions are a useful tool for fluid identification. Linear Q-factor inversions are commonly used, but nonlinear inversions based on exact equations with higher precision and fewer assumptions are occasionally carried out. This study proposes a frequency-dependent reflection coefficient equation and a novel two-stage broadband frequency-dependent nonlinear inversion approach for Q-factors, which can accurately estimate Q-factors and identify fluids in oil and gas exploration and reservoir identification.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2023)
Article
Acoustics
Tianzhu Wang, Qian Ding
Summary: This investigation examines the energy flow characteristics of a bistable nonlinear energy sink coupled with a nonlinear oscillator, and demonstrates the nonlinear normal modes and dynamic behavior of the NO-BNES system through frequency-energy graphs. The emergence of many symmetrical and asymmetrical in-phase and out-of-phase backbone branches is emphasized at low energy levels. The wavelet frequency spectra validate the robustness of the TET mechanism, and the superiority of the BNES over the cubic NES in TET is confirmed by comparing the superimposed wavelet frequency spectra on FEPs and energy dissipation efficiency.
JOURNAL OF SOUND AND VIBRATION
(2023)
Article
Engineering, Electrical & Electronic
Yonghui Nie, Jiatong Liu, Lei Gao, Yongqing Wu, Zongkai Li
Summary: Large-scale wind power integration reduces the frequency stability of power systems by decreasing their level of inertia. To address this issue, a nonlinear rotor kinetic release control strategy is designed for wind power grid-connected systems based on an extended state observer (ESO) and nonlinear feedforward state feedback transformation (NFSFT) theories. The strategy establishes a basic equivalent linear system using NFSFT theory, obtains a nonlinear control law, and utilizes ESO to observe the generalized disturbance caused by the control law. Simulation results verify that the proposed strategy outperforms other strategies in terms of frequency regulation.
ELECTRIC POWER SYSTEMS RESEARCH
(2023)
Article
Physics, Multidisciplinary
Xingyu Zhang, Xiaoguang Wang
Summary: The interacting model describing the Rabi transition is essential in studying atom-photon interactions, where the kinetic energy term is often neglected for the convenience of analysis. The approximation becomes valid as the radiation field's momentum and the absolute value of detuning decrease. It is noted that a specific choice of the initial Gaussian state's variance in position space can improve measuring accuracy when considering the kinetic energy term.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2021)
Article
Engineering, Mechanical
Zhi-Ya Pang, Zhi-Sai Ma, Qian Ding, Tianzhi Yang
Summary: This paper proposes an improved approach for nonlinear system identification by using a separation strategy in the nonlinear separation identification through feedback of the outputs (NSIFO) method. The method aims to reduce coupling errors and expand the excitation level selection range, demonstrating superior accuracy and stability compared to the existing NIFO method through numerical and experimental validation.
NONLINEAR DYNAMICS
(2021)
Article
Meteorology & Atmospheric Sciences
Charles X. Light, Brian K. Arbic, Paige E. Martin, Laurent Brodeau, J. Thomas Farrar, Stephen M. Griffies, Ben P. Kirtman, Lucas C. Laurindo, Dimitris Menemenlis, Andrea Molod, Arin D. Nelson, Ebenezer Nyadjro, Amanda K. O'Rourke, Jay F. Shriver, Leo Siqueira, R. Justin Small, Ehud Strobach
Summary: This paper investigates high-frequency variability of precipitation using various models and methods, and finds that high-resolution models yield results closer to observations. Increasing model grid spacing generally increases high-frequency precipitation variance in climate modeling.
Article
Oceanography
Keshav J. Raja, Maarten C. Buijsman, Jay F. Shriver, Brian K. Arbic, Oladeji Siyanbola
Summary: This study investigates the generation, propagation, and dissipation of wind-generated near-inertial waves (NIWs) in a global ocean with realistic atmospheric forcing and background circulation. The results show that most of the NIW energy is dissipated in lower latitudes, and cyclonic and anticyclonic vorticity play a crucial role in the distribution of NIW energy. The locally dissipated fraction of NIW energy is uniform throughout the global ocean.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2022)
Review
Oceanography
Brian K. Arbic
Summary: This article reviews an emerging class of high-resolution global models that consider the effects of both atmospheric fields and astronomical tidal potentials, and can simulate various oceanic phenomena. These models have numerous applications in satellite oceanography, operational oceanography, boundary forcing, tidal-cryosphere interactions, and assessment of the impact of tidal changes on future coastal flooding hazards.
PROGRESS IN OCEANOGRAPHY
(2022)
Article
Geosciences, Multidisciplinary
Ritabrata Thakur, Brian K. Arbic, Dimitris Menemenlis, Kayhan Momeni, Yulin Pan, W. R. Peltier, Joseph Skitka, Matthew H. Alford, Yuchen Ma
Summary: We propose improvements to the modeling of the vertical wavenumber spectrum of internal gravity waves in regional ocean simulations. Our study focuses on the sensitivity of the model to mixing parameters and compares the results to observations. The findings suggest that improving the mixing parameters can enhance the representation of internal wave dynamics.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Eliana B. Crawford, Brian K. Arbic, Nathan D. Sheldon, Joseph K. Ansong, Patrick G. Timko
Summary: Research suggests that mid-Archean ocean tides were stronger and more frequent than modern tides, potentially impacting marine productivity. These findings indicate the importance of considering ancient tidal forces when studying Precambrian marine ecosystems.
PRECAMBRIAN RESEARCH
(2022)
Article
Meteorology & Atmospheric Sciences
Kristin N. Barton, Nairita Pal, Steven R. Brus, Mark R. Petersen, Brian K. Arbic, Darren Engwirda, Andrew F. Roberts, Joannes J. Westerink, Damrongsak Wirasaet, Michael Schindelegger
Summary: In this study, we used the barotropic version of the Model for Prediction Across Scales (MPAS-Ocean) to examine ocean tides and investigate factors affecting tidal accuracy. We compared different methods of calculating self-attraction and loading (SAL), different model resolutions, details of bathymetry, and parameterized topographic wave drag. We also compared the performance of different resolution meshes and found that a variable resolution mesh obtained the best accuracy for deep ocean M2 tide. In future work, we plan to use MPAS-Ocean to study tidal interactions with other Earth system components and the response of tides to climate change.
JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS
(2022)
Article
Oceanography
Brian K. Arbic, Shane Elipot, Jonathan M. Brasch, Dimitris Menemenlis, Aurelien L. Ponte, Jay F. Shriver, Xiaolong Yu, Edward D. Zaron, Matthew H. Alford, Maarten C. Buijsman, Ryan Abernathey, Daniel Garcia, Lingxiao Guan, Paige E. Martin, Arin D. Nelson
Summary: The study investigates the geographical variability, frequency content, and vertical structure of near-surface oceanic kinetic energy and compares it with high-resolution global simulations and drifter observations. The results show that the models generally agree with the drifter observations, although there are some differences in certain frequency bands and latitudes.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Oceanography
Xiaobiao Xu, Eric P. Chassignet, Alan J. Wallcraft, Brian K. Arbic, Maarten C. Buijsman, Miguel Solano
Summary: This study investigates the impacts of internal tides, high-resolution bathymetry, and high-frequency atmospheric variability on the sea surface height (SSH) wavenumber spectra in the Atlantic Ocean. The results show that including internal tides increases high-frequency SSH variability and flattens the spectra slope, and the spatial variability of the spectral slope in the Atlantic is primarily due to the surface signature of internal tides.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Meteorology & Atmospheric Sciences
Oladeji Q. Siyanbola, Maarten C. Buijsman, Audrey Delpech, Lionel Renault, Roy Barkan, Jay F. Shriver, Brian K. Arbic, James C. McWilliams
Summary: This study investigates the impact of remotely generated internal waves on the internal wave energetics near the U.S. West Coast using realistic regional ocean simulations. The results show that internal tide reflections can be as high as 73%, although they are reduced with increased sponge viscosity and/or sponge layer width. The presence of remote internal waves improves the model's variance and spatial correlations, making it more consistent with mooring and altimetry datasets. However, excessive reflections of internal waves from the interior should be avoided at the open boundaries.
Article
Meteorology & Atmospheric Sciences
Steven R. Brus, Kristin N. Barton, Nairita Pal, Andrew F. Roberts, Darren Engwirda, Mark R. Petersen, Brian K. Arbic, Damrongsak Wirasaet, Joannes J. Westerink, Michael Schindelegger
Summary: Self attraction and earth-loading effects are important for accurately modeling global tides. We investigate two different approaches to perform these calculations for ocean models that employ unstructured meshes and distributed memory parallelization. Our results show that the scalability of the unstructured mesh approach allows for more efficient spherical harmonics transforms for high-resolution meshes and large processor counts, enabling the efficient inclusion of tidal dynamics in large-scale Earth system model simulations.
Article
Meteorology & Atmospheric Sciences
Gaspard Geoffroy, Jonas Nycander, Maarten C. Buijsman, Jay F. Shriver, Brian K. Arbic
Summary: The autocovariance of the semidiurnal internal tide (IT) is examined using the HYCOM model, which shows a globally low bias in terms of IT variance and decay of the IT autocovariance. Except in the Southern Ocean, the spatial correlation between the model and observational data suggests that the generation of semidiurnal ITs is well captured by the model.
Article
Geosciences, Multidisciplinary
Nairita Pal, Kristin N. Barton, Mark R. Petersen, Steven R. Brus, Darren Engwirda, Brian K. Arbic, Andrew F. Roberts, Joannes J. Westerink, Damrongsak Wirasaet
Summary: This paper presents the implementation of tides in MPAS-Ocean, which overcomes the limitation of low resolution by using unstructured global meshing. The tidal constituents calculated using MPAS-Ocean closely agree with the results of the global tidal prediction model TPXO8. The presence of Antarctic ice shelf cavities affects the amplitude and phase of tidal constituents, with lower complex errors observed when simulating with ice shelves.
GEOSCIENTIFIC MODEL DEVELOPMENT
(2023)
Article
Geosciences, Multidisciplinary
Takaya Uchida, Julien Le Sommer, Charles Stern, Ryan P. Abernathey, Chris Holdgraf, Aurelie Albert, Laurent Brodeau, Eric P. Chassignet, Xiaobiao Xu, Jonathan Gula, Guillaume Roullet, Nikolay Koldunov, Sergey Danilov, Qiang Wang, Dimitris Menemenlis, Clement Bricaud, Brian K. Arbic, Jay F. Shriver, Fangli Qiao, Bin Xiao, Arne Biastoch, Rene Schubert, Baylor Fox-Kemper, William K. Dewar, Alan Wallcraft
Summary: With the increase in computational power, higher-resolution ocean models have been developed, but the larger data size poses challenges for data transfer and analysis. A cloud-based analysis framework is proposed to address these challenges, allowing for more efficient and collaborative analysis of model outputs.
GEOSCIENTIFIC MODEL DEVELOPMENT
(2022)
Article
Development Studies
Erich K. Eberhard, Jessica Hicks, Adam C. Simon, Brian K. Arbic
WORLD DEVELOPMENT PERSPECTIVES
(2022)