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Research note: Application of refraction full-waveform inversion of ocean bottom node data using a squared-slowness model parameterization

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GEOPHYSICAL PROSPECTING 2024年第3期72卷 1189-1195页

作者： da Silva, Sergio Luiz Costa, Felipe Karsou, Ammir Capuzzo, Felipe Moreira, Roger Lopez, Jorge Cetale, Marco Fluminense Fed Univ GISIS Niteroi Brazil Politecn Torino Dipartimento Sci Applicata & Tecnol Turin Italy Shell Brasil Petr Ltda Rio De Janeiro Brazil Fluminense Fed Univ GISIS BR-24210346 Niteroi RJ Brazil

Full-waveform inversion is a wave equation-based imaging technique for obtaining subsurface model parameters by matching modelled with field data. Full-waveform inversion is often formulated as a local optimization problem in which the model parameterization influences the gradient preconditioner and the convergence rate associated with the full-waveform inversion objective function. model parameterization governs the radiation pattern of the so-called secondary Born source. In this work, we assess model parameterization effects on the estimation of P-wave velocities using a three-dimensional acoustic time-domain full-waveform inversion procedure. These include the three commonly used parameterization: velocity, slowness and squared slowness. In this context, we consider a field data set from a deepwater Brazilian pre-salt field using a recently introduced circular shot ocean bottom node acquisition which favours refracted waves. The results reveal that the squared slowness model parameterization provides a satisfactory trade-off between the reconstruction of the deep pre-salt target area and convergence rate, saving 50% of runtime compared to the velocity and slowness cases.

关键词： Full waveform Inversion Circular shot acquisition model parameterization ocean bottom nodes subsalt imaging

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Investigation on the Sensitivity of Precipitation Simulation to model parameterization and Analysis Nudging over Hebei Province, China

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ATMOSPHERE 2024年第4期15卷 512页

作者： Li, Yuanhua Tian, Zhiguang Chen, Xia Su, Xiashu Yu, Entao Hebei Meteorol Informat Ctr Shijiazhuang 050021 Peoples R China Hebei Climate Ctr Shijiazhuang 050021 Peoples R China Hebei Key Lab Meteorol & Ecoenvironm Shijiazhuang 050021 Peoples R China Inner Mongolia Univ Sch Ecol & Environm Hohhot 010021 Peoples R China Chinese Acad Sci Inst Atmospher Phys Nansen Zhu Int Res Ctr Beijing 100029 Peoples R China Nanjing Univ Informat Sci & Technol Collaborat Innovat Ctr Forecast & Evaluat Meteorol Nanjing 210044 Peoples R China

The physical parameterizations have important influence on model performance in precipitation simulation and prediction;however, previous investigations are seldom conducted at very high resolution over Hebei Province, which is often influenced by extreme events such as droughts and floods. In this paper, the influence of parameterization schemes and analysis nudging on precipitation simulation is investigated using the WRF (weather research and forecasting) model with many sensitivity experiments at the cumulus "gray-zone" resolution (5 km). The model performance of different sensitivity simulations is determined by a comparison with the local high-quality observational data. The results indicate that the WRF model generally reproduces the distribution of precipitation well, and the model tends to underestimate precipitation compared with the station observations. The sensitivity simulation with the Tiedtke cumulus parameterization scheme combined with the Thompson microphysics scheme shows the best model performance, with the highest temporal correlation coefficient (0.45) and lowest root mean square error (0.34 mm/day). At the same time, analysis nudging, which incorporates observational information into simulation, can improve the model performance in precipitation simulation. Further analysis indicates that the negative bias in precipitation may be associated with the negative bias in relative humidity, which in turn is associated with the positive bias in temperature and wind speed. This study highlights the role of parameterization schemes and analysis nudging in precipitation simulation and provides a valuable reference for further investigations on precipitation forecasting applications.

关键词： precipitation simulation Heibei Province model parameterization analysis nudging

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Impact of WRF model parameterization Settings on the Quality of Short-Term Weather Forecasts over Poland

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ATMOSPHERE 2024年第12期15卷 1425-1425页

作者： Kendzierski, Sebastian Adam Mickiewicz Univ Dept Meteorol & Climatol PL-61608 Poznan Poland

This research examines the impact of various parameterization settings within the Weather Research and Forecasting (WRF) model on the accuracy of short-term weather forecasts for Poland. The study focuses on the sensitivity of key meteorological variables-namely, air temperature, wind speed, relative humidity, and atmospheric pressure-to different combinations of physical parameterization schemes. Utilizing data from the Global Forecast System (GFS) spanning 2019 to 2022, a series of model simulations were conducted with support from the Pozna & nacute;Supercomputing and Networking Center (PCSS). To assess the model's performance across different weather stations, statistical metrics such as the mean absolute error (MAE) and root mean square error (RMSE) were employed. The findings indicate that the configuration labeled "p2" produced the most accurate forecasts for temperature, wind speed, and atmospheric pressure, achieving MAE values of 1.5 degrees C, 1.6 m/s, and 2 hPa, respectively. However, forecast inaccuracies were notably higher in mountainous regions, particularly regarding wind speed. These results underscore the importance of selecting appropriate parameterization settings tailored to regional characteristics, as different configurations can significantly impact the forecast accuracy, especially in complex terrains. This study contributes to the understanding of short-term weather forecasting models for Central Europe, offering potential pathways for improving localized forecast accuracy.

关键词： model parameterization numerical weather prediction WRF model

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Diesel Generator model parameterization for Microgrid Simulation Using Hybrid Box-Constrained Levenberg-Marquardt Algorithm

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IEEE TRANSACTIONS ON SMART GRID 2021年第2期12卷 943-952页

作者： Long, Qian Yu, Hui Xie, Fuhong Lu, Ning Lubkeman, David North Carolina State Univ Dept Elect & Comp Engn Raleigh NC 27606 USA

Existing generator parameterization methods, typically developed for large turbine generator units, are difficult to apply to small kW-level diesel generators in microgrid applications. This article presents a model parameterization method that estimates a complete set of kW-level diesel generator parameters simultaneously using only load-step-change tests with limited measurement points. This method provides a more cost-efficient and robust approach to achieve high-fidelity modeling of diesel generators for microgrid dynamic simulation. A two-stage hybrid box-constrained Levenberg-Marquardt (H-BCLM) algorithm is developed to search the optimal parameter set given the parameter bounds. A heuristic algorithm, namely Generalized Opposition-based Learning Genetic Algorithm (GOL-GA), is applied to identify proper initial estimates at the first stage, followed by a modified Levenberg-Marquardt algorithm designed to fine tune the solution based on the first-stage result. The proposed method is validated against dynamic simulation of a diesel generator model and field measurements from a 16kW diesel generator unit.

关键词： Generators Mathematical model Heuristic algorithms Load modeling Microgrids Diesel engines Synchronous generators Diesel generators model parameterization microgrid dynamic simulation Levenberg-Marquardt

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3-D Seismic Inversion by model parameterization With Fourier Coefficients

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IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 2023年 61卷 1页

作者： Gao, Fengxia Rao, Ying Zhu, Tong Wang, Yanghua Chinese Acad Geol Sci SinoProbe Ctr Beijing Peoples R China China Geol Survey Beijing 100037 Peoples R China China Univ Petr Coll Geophys Beijing 102249 Peoples R China Sinopec Geophys Res Inst Co Ltd Nanjing 211103 Peoples R China Imperial Coll London Resource Geophys Acad Ctr Reservoir Geophys London SW7 2BP England

In seismic inversion, the subsurface model can be parameterized by a truncated Fourier series, and then, the inversion problem is the inversion of the Fourier coefficients. To improve the efficiency of the evaluation of the Fourier coefficients and the reconstruction of the model from the inverted coefficients, we propose to use the efficient implementation of the fast Fourier transform (FFT) to speed up these two calculations. By using the FFT pair, the computation time for 3-D subsurface models with realistic size could be reduced by two-three orders of magnitude compared to conventional methods. When this model parameterization scheme is applied to seismic impedance inversion, we have proposed two strategies to further improve the efficiency. One is to invert the Fourier coefficients from small-valued numbers to large-valued numbers, and the other is to divide the seismic data into subgroups and use part of them for the inversion of the Fourier coefficients. Both strategies are helpful for efficient inversion of the Fourier coefficients from the seismic data. Moreover, thanks to this model parameterization scheme, the Fourier coefficients are inverted in a multitrace manner, and the impedance model reconstructed from the inverted Fourier coefficients has a good spatial continuity. The scheme can generate stable and continuous impedance models from the inversion of seismic data with missing traces, with affordable computation times.

关键词： Computational modeling Three-dimensional displays Solid modeling Fourier series Impedance Fourier transforms Data models Fourier transform model parameterization seismic inversion

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Development of a Database for model parameterization, Tire Performance Evaluation, and Analysis of In-Plane Spindle Forces

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SAE INTERNATIONAL JOURNAL OF VEHICLE DYNAMICS STABILITY AND NVH 2021年第3期5卷 279-290页

作者： Pang, Yun Prokop, Guenther Tech Univ Dresden Dresden Germany

Tires are one of the most important vehicle components since they significantly affect vehicle attributes such as handling stability, steering controllability, ride comfort, and structure durability. However, whether for tire competitive benchmarking or vehicle conceptual design, data insufficiency tends to restrict the development process. This article presents a procedure of establishing a database for the evaluation of tire and vehicle impact vibration. Forty-three tires with various sizes and usages were selected to build the datasets. The rigid ring model was used to characterize each individual tire sample on account of our application requests. In view of the test resources, an optimization approach to the standard parameterization method was proposed and fully validated with the measurement database. The parameter characteristics were then statistically investigated and compared between the different tire types. A criterion "peak-to-peak" was put forward to quantitatively assess the spindle responses by impact cleat. In-plane spindle forces were finally analyzed regarding the tire properties based on the parameter database.

关键词： Tire database Rigid ring model model parameterization Parametric analysis In-plane spindle forces

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model parameterization and amplitude variation with angle and azimuthal inversion in orthotropic media

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GEOPHYSICS 2021年第1期86卷 R1-R14页

作者： Zong, Zhaoyun Ji, Lixiang China Univ Petr Qingdao 266555 Peoples R China Lab Marine Mineral Resources Qingdao Natl Lab Marine Sci & Technol Qingdao 266555 Peoples R China

Horizontal layered formations with a suite of vertical or near-vertical fractures are usually assumed to be an approximate orthotropic medium and are more suitable for estimating f racture properties with wide-azimuth prestack seismic data in shale reservoirs. However, the small contribution of anisotropic parameters to the reflection coefficients highly reduces the stability of anisotropic parameter estimation by using seismic inversion approaches. Therefore, a novel model parameterization approach for the reflectivity and a pragmatic inversion method are proposed to enhance the stability of the inversion for orthotropic media. Previous attempts to characterize orthotropic media properties required using four or five independent parameters. However, we have derived a novel formulation that reduces the number of parameters to three. The inversion process is better conditioned with fewer degrees of freedom. An accuracy comparison of our formula with the previous ones indicates that our approach is sufficiently precise for reasonable parameter estimation. Furthermore, a Bayesian inversion method is developed that uses the amplitude variation with angle and azimuth (AVAZ) of the seismic data. Smooth background constraints reduce the similarity between the inversion result and the initial model, thereby reducing the sensitivity of the initial model to the inversion result. Cauchy and Gaussian probability distributions are used as prior constraints on the model parameters and the likelihood function, respectively. These ensure that the results are within the range of plausibility. Synthetic examples demonstrate that the adopted orthotropic AVAZ inversion method is feasible for estimating the anisotropic parameters even with moderate noise. The field data example illustrates the inversion robustness and stability of the adopted method in a fractured reservoir with a single well control.

关键词： wide-azimuth orthotropic medium model parameterization Bayesian inversion AVAZ

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Sensitivity of the Urban Boundary Layer to model parameterization

Sensitivity of the Urban Boundary Layer to Model Parameteriz...

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作者： Wermter, Joseph E. University of Kansas

学位级别：M.S., Master of Science/Master of Surgery

Continued urbanization and a warming climate will exacerbate the urban heat island (UHI) and aggravate health risks of urban populations. In addition to satellite and surface observations, high resolution numerical simulations are often used to study the UHI. Less attention is typically given to the urban boundary layer (UBL) mainly because upper-air observations are sparse or limited to short field campaigns, which also makes verification of model profiles challenging. The continued growth of observations from the Aircraft Meteorological Data Relay (AMDAR) provides essential measurements of the lower atmosphere, which are collected by many commercial airplanes during landing and takeoff. AMDAR data from airports reasonably close to urban centers yields many profiles of the UBL per day that can be used to evaluate model performance and better understand the lower atmosphere over urban areas. The Weather Research and Forecasting (WRF) modelling system is used to simulate the urban environment of the Dallas-Fort Worth metropolitan area during recent heat waves. model output is evaluated using AMDAR soundings from two airports (DFW and DAL) to not only assess overall performance but also to help identify specific model deficiencies and highlight the important role of the lower atmosphere in influencing surface temperatures and the magnitude of the urban heat island. Focus is placed on the interaction of urban canopy model and planetary boundary layer (PBL) schemes. Major differences are found in the lower atmosphere primarily in the morning and evening hours with the most similar profiles during the daytime. Warm biases are often present at the surface in the model and are related to deeper mixing in the model than observed. Morning observations often indicate a shallow mixed layer near the surface capped by a stable layer associated with a temperature inversion or an isothermal layer. Some cases reveal situations where the layer of stability is not captured by the mod

关键词： Urban boundary layer model parameterization Urban heat island Aircraft meteorological data relay Weather research and forecasting Planetary boundary layer

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Impact of model parameterization on predictive uncertainty of regional groundwater models in the context of environmental impact assessment

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ENVIRONMENTAL IMPACT ASSESSMENT REVIEW 2021年 90卷 106620-106620页

作者： Cui, Tao Sreekanth, J. Pickett, Trevor Rassam, David Gilfedder, Mat Barrett, Damian CSIRO Land & Water Dutton Park 4102 Australia CSIRO Energy Canberra ACT 2601 Australia

parameterization strategy impacts models' outputs and the associated uncertainty. This is particularly true for transient regional groundwater models where parameters can only be weakly constrained by insufficient observations. However, this is rarely investigated under any particular model structure. This study bridges this gap using a regional groundwater model developed to understand the impact of coal seam gas extraction on groundwater systems in a probabilistic framework. Two different parameterization schemes were implemented for hydraulic conductivity and specific storage. The first method solely relies on the relationship between hydraulic properties and burial depths. The second more complex strategy allows more spatial variations of hydraulic parameters using pilot points. The study provides new insights and practical guidance on the application of groundwater modelling for environmental impact assessment. The results suggest that the choice of model parameterization has a significant influence on predictive uncertainty. The model using the simple parameterization provides predictions with a much wider range than the model with a more sophisticated parameterization. This is because that the lowly parameterized model tends to generate more extreme effective hydraulic parameter fields unless the parameterization simplification converts the inverse problem to a (close to) wellposed problem that rarely exists for applied regional groundwater modelling. The potential impact of model parameterization should be discussed explicitly in groundwater modelling applications to support decision making to avoid misinterpretation of the modelling results.

关键词： Groundwater modelling Uncertainty analysis model complexity model simplification model parameterization

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An Improved Optimization Algorithm Combined model parameterization and Sequential Quadratic Programming

An Improved Optimization Algorithm Combined Model Parameteri...

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2016 3rd International Conference on Materials Engineering,Manufacturing Technology and Control(ICMEMTC 2016)

作者： Weiwei Bian Zhenfang Xin Beijing Machine and Equipment Institute

According to the nonlinear problem of the trajectory optimization problem of rocket projectile, an improved optimization algorithm combined the direct model parameterization method and the sequential quadratic programming method was proposed. The direct numerical method was presented to converts the infinite dimensional optimization problem into a finite dimensional nonlinear programming problem. The improved sequential quadratic programming algorithm was derived by making a special treatment on the constraint conditions. Taking the range as the independent variable instead of the time, and taking the maximum range trajectory and the shortest f time trajectory as the function of the performance index respectively, the trajectory optimization model was presented, and the numerical simulations were carried out. The results show that the proposed algorithm is effective to solve the trajectory optimization problem.

关键词： model parameterization Sequential Quadratic Programming Trajectory Optimization

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