Relevant bibliographies by topics / Parameterizations

Academic literature on the topic 'Parameterizations'

Author: Grafiati
Published: 4 June 2021
Last updated: 29 January 2023

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Journal articles on the topic "Parameterizations"

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Kuznetsova, Alexandra, Georgy Baydakov, Vladislav Papko, Alexander Kandaurov, Maxim Vdovin, Daniil Sergeev, and Yuliya Troitskaya. "Adjusting of Wind Input Source Term in WAVEWATCH III Model for the Middle-Sized Water Body on the Basis of the Field Experiment." Advances in Meteorology 2016 (2016): 1–13. http://dx.doi.org/10.1155/2016/8539127.

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Adjusting of wind input source term in numerical model WAVEWATCH III for the middle-sized water body is reported. For this purpose, the field experiment on Gorky Reservoir is carried out. Surface waves are measured along with the parameters of the airflow. The measurement of wind speed in close proximity to the water surface is performed. On the basis of the experimental results, the parameterization of the drag coefficient depending on the 10 m wind speed is proposed. This parameterization is used in WAVEWATCH III for the adjusting of the wind input source term within WAM 3 and Tolman and Chalikov parameterizations. The simulation of the surface wind waves within tuned to the conditions of the middle-sized water body WAVEWATCH III is performed using three built-in parameterizations (WAM 3, Tolman and Chalikov, and WAM 4) and adjusted wind input source term parameterizations. Verification of the applicability of the model to the middle-sized reservoir is performed by comparing the simulated data with the results of the field experiment. It is shown that the use of the proposed parameterizationCD(U10)improves the agreement in the significant wave heightHSfrom the field experiment and from the numerical simulation.
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Jin, Han-Gyul, Hyunho Lee, and Jong-Jin Baik. "A New Parameterization of the Accretion of Cloud Water by Graupel and Its Evaluation through Cloud and Precipitation Simulations." Journal of the Atmospheric Sciences 76, no. 2 (January 21, 2019): 381–400. http://dx.doi.org/10.1175/jas-d-18-0245.1.

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Abstract A new parameterization of the accretion of cloud water by graupel for use in bulk microphysics schemes is derived by analytically integrating the stochastic collection equation (SCE). In this parameterization, the collection efficiency between graupel particles and cloud droplets is expressed in a functional form using the data obtained from a particle trajectory model by a previous study. The new accretion parameterization is evaluated through box model simulations in comparison with a bin-based direct SCE solver and two previously developed accretion parameterizations that employ the continuous collection equation and a simplified SCE, respectively. Changes in cloud water and graupel mass contents via the accretion process predicted by the new parameterization are closest to those predicted by the direct SCE solver. Furthermore, the new parameterization predicts a decrease in the cloud droplet number concentration that is smaller than the decreases predicted by the other accretion parameterizations, consistent with the direct SCE solver. The new and the other accretion parameterizations are implemented into a cloud-resolving model. Idealized deep convective cloud simulations show that among the accretion parameterizations, the new parameterization predicts the largest rate of accretion by graupel and the smallest rate of accretion by snow, which overall enhances rainfall through the largest rate of melting of graupel. Real-case simulations for a precipitation event over the southern Korean Peninsula show that among the examined accretion parameterizations, the new parameterization simulates precipitation closest to observations. Compared to the other accretion parameterizations, the new parameterization decreases the fractions of light and moderate precipitation amounts and increases the fraction of heavy precipitation amount.
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Liu, Yangang, Peter H. Daum, R. McGraw, and R. Wood. "Parameterization of the Autoconversion Process. Part II: Generalization of Sundqvist-Type Parameterizations." Journal of the Atmospheric Sciences 63, no. 3 (March 1, 2006): 1103–9. http://dx.doi.org/10.1175/jas3675.1.

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Abstract Existing Sundqvist-type parameterizations, which only consider dependence of the autoconversion rate on cloud liquid water content, are generalized to explicitly account for the droplet concentration and relative dispersion of the cloud droplet size distribution as well. The generalized Sundqvist-type parameterization includes the more commonly used Kessler-type parameterization as a special case, unifying the two different types of parameterizations for the autoconversion rate. The generalized Sundqvist-type parameterization is identical with the Kessler-type parameterization presented in Part I beyond the autoconversion threshold, but exhibits a more realistic, smooth transition in the vicinity of the autoconversion threshold (threshold behavior) in contrast to the discontinuously abrupt transition embodied in the Kessler-type parameterization. A new Sundqvist-type parameterization is further derived by applying the expression for the critical radius derived from the kinetic potential theory to the generalized Sundqvist-type parameterization. The new parameterization eliminates the need for defining the driving radius and for prescribing the critical radius associated with Kessler-type parameterizations. The two-part structure of the autoconversion process raises questions regarding model-based empirical parameterizations obtained by fitting simulation results from detailed collection models with a single function.
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BAJAJ, CHANDRAJIT L., and ANDREW V. ROYAPPA. "FINITE REPRESENTATIONS OF REAL PARAMETRIC CURVES AND SURFACES." International Journal of Computational Geometry & Applications 05, no. 03 (September 1995): 313–26. http://dx.doi.org/10.1142/s0218195995000180.

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Global parameterizations of parametric algebraic curves or surfaces are defined over infinite parameter domains. Considering parameterizations in terms of rational functions that have real coefficients and vary over real parameter values, we show how to replace one global parameterization with a finite number of alternate bounded parameterizations, each defined over a fixed, bounded part of the real parameter domain space. The new bounded parameterizations together generate all real points of the old one and in particular the points corresponding to infinite parameter values in the old domain. We term such an alternate finite set of bounded parameterizations a finite representation of a real parametric curve or surface. Two solutions are presented for real parametric varieties of arbitrary dimension n. In the first method, a real parametric variety of dimension n is finitely represented in a piecewise fashion by 2n bounded parameterizations with individual pieces meeting with C∞ continuity; each bounded parameterization is a map from a unit simplex of the real parameter domain space. In the second method, only a single bounded parameterization is used; it is a map from the unit hypersphere centered at the origin of the real parameter domain space. Both methods start with an arbitrary real parameterization of a real parametric variety and apply projective domain transformations of different types to yield the new bounded parameterizations. Both these methods are implementable in a straightforward fashion. Applications of these results include displaying entire real parametric curves and surfaces (except those real points generated by complex parameter values), computing normal parameterizations of curves and surfaces (settling an open problem for quadric surfaces).
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Wang, Wenping, Barry Joe, and Ronald Goldman. "Rational Quadratic Parameterizations of Quadrics." International Journal of Computational Geometry & Applications 07, no. 06 (December 1997): 599–619. http://dx.doi.org/10.1142/s0218195997000375.

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Every irreducible quadric in E3 has infinitely many different rational quadratic parameterizations. These parameterizations and the relationships between them are investigated. It is shown that every faithful rational quadratic parameterization of a quadric can be generated by a stereographic projection from a point on the quadric, called the center of projection (COP). Two such parameterizations for the same quadric are related by a rational linear reparameterization if they have the same COP; otherwise they are related by a rational quadratic reparameterization. We also consider unfaithful parameterizations for which, in general, a one-to-one correspondence between points on the surface and parameters in the plane does not exist. It is shown that all unfaithful rational quadratic parameterizations of a properly degenerate quadric can be characterized by a simple canonical form, and there exist no unfaithful rational quadratic parameterizations for a nondegenerate quadric. In addition, given a faithful rational quadratic parameterization of a quadric, a new technique is presented to compute its base points and inversion formula. These results are applied to solve the problems of parameterizing the intersection of two quadrics and reparameterizing a given quadric parameterization with respect to a different COP without implicitization.
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Lee, Hyunho, and Jong-Jin Baik. "A Physically Based Autoconversion Parameterization." Journal of the Atmospheric Sciences 74, no. 5 (May 1, 2017): 1599–616. http://dx.doi.org/10.1175/jas-d-16-0207.1.

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Abstract A physically based parameterization for the autoconversion is derived by solving the stochastic collection equation (SCE) with an approximated collection kernel. The collection kernel is constructed using the terminal velocity of cloud droplets and the collision efficiency between cloud droplets that is obtained using a particle trajectory model. The new parameterization proposed in this study is validated through comparison with results obtained by a bin-based direct SCE solver and other autoconversion parameterizations using a box model. The autoconversion-related time scale and drop number concentration are employed for the validation. The results of the new parameterization are shown to most closely match those of the direct SCE solver. It is also shown that the dependency of the autoconversion rate on drop number concentration in the new parameterization is similar to that in the direct SCE solver, which is partially caused by the shape of drop size distribution. The new parameterization and other parameterizations are implemented into a cloud-resolving model, and idealized shallow warm clouds are simulated. The autoconversion parameterizations that yield the small (large) autoconversion rate tend to predict large (small) cloud optical thickness, small (large) cloud fraction, and small (large) surface precipitation amount. Cloud optical thickness and cloud fraction are changed by up to ~45% and ~20% by autoconversion parameterizations, respectively. The new parameterization tends to yield the moderate autoconversion rate among the autoconversion parameterizations. Moreover, it predicts cloud optical thickness, cloud fraction, and surface precipitation amount that are generally the closest to those of the bin microphysics scheme.
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Xu, Shibo, and Alexey Stovas. "A new parameterization for acoustic orthorhombic media." GEOPHYSICS 82, no. 6 (November 1, 2017): C229—C240. http://dx.doi.org/10.1190/geo2017-0215.1.

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We have defined a group of new parameterizations for P-wave in acoustic orthorhombic (ORT) media with three cross-term normal moveout velocities and three cross-term anellipticity parameters. The corresponding perturbation-based approximations for traveltime in ORT model are developed using the new parameterizations. The perturbation coefficients are computed by solving the eikonal equation in corresponding parameterization. Eight types of parameterization are defined based on the different elliptical background model and selection of anellipticity parameters. As the traveltime can be converted from the group velocity inverse, the sensitivity of the group velocity inverse to anellipticity parameters is analyzed for different parameterizations and different range of offsets. To stabilize the perturbation series and improve the accuracy, the Shanks transform is applied. From the comparison of traveltime after the Shanks transform using different parameterizations, we have concluded that the parameterization with vertical, two horizontal velocities, and three cross-term anellipticity parameters results in the best accuracy of traveltime function for P-wave in acoustic ORT medium.
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Song, Yong, Christopher K. Wikle, Christopher J. Anderson, and Steven A. Lack. "Bayesian Estimation of Stochastic Parameterizations in a Numerical Weather Forecasting Model." Monthly Weather Review 135, no. 12 (December 1, 2007): 4045–59. http://dx.doi.org/10.1175/2007mwr1928.1.

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Abstract Parameterizations in numerical models account for unresolved processes. These parameterizations are inherently difficult to construct and as such typically have notable imperfections. One approach to account for this uncertainty is through stochastic parameterizations. This paper describes a methodological approach whereby existing parameterizations provide the basis for a simple stochastic approach. More importantly, this paper describes systematically how one can “train” such parameterizations with observations. In particular, a stochastic trigger function has been implemented for convective initiation in the Kain–Fritsch (KF) convective parameterization scheme within the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (Penn State–NCAR) Mesoscale Model (MM5). In this approach, convective initiation within MM5 is modeled by a binary random process. The probability of initiation is then modeled through a transformation in terms of the standard KF trigger variables, but with random parameters. The distribution of these random parameters is obtained through a Bayesian Monte Carlo procedure informed by radar reflectivities. Estimates of these distributions are then incorporated into the KF trigger function, giving a meaningful stochastic (distributional) parameterization. The approach is applied to cases from the International H2O project (IHOP). The results suggest the stochastic parameterization/Bayesian learning approach has potential to improve forecasts of convective precipitation in mesoscale models.
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Pan, Wenyong, Kristopher A. Innanen, Yu Geng, and Junxiao Li. "Interparameter trade-off quantification for isotropic-elastic full-waveform inversion with various model parameterizations." GEOPHYSICS 84, no. 2 (March 1, 2019): R185—R206. http://dx.doi.org/10.1190/geo2017-0832.1.

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Simultaneous determination of multiple physical parameters using full-waveform inversion (FWI) suffers from interparameter trade-off difficulties. Analyzing the interparameter trade-offs in different model parameterizations of isotropic-elastic FWI, and thus determining the appropriate model parameterization, are critical for efficient inversion and obtaining reliable inverted models. Five different model parameterizations are considered and compared including velocity-density, modulus-density, impedance-density, and two velocity-impedance parameterizations. The scattering radiation patterns are first used for interparameter trade-off analysis. Furthermore, a new framework is developed to evaluate the interparameter trade-off based upon multiparameter Hessian-vector products: Multiparameter point spread functions (MPSFs) and interparameter contamination sensitivity kernels (ICSKs), which provide quantitative, second-order measurements of the interparameter contaminations. In the numerical experiments, the interparameter trade-offs in various model parameterizations are evaluated using the MPSFs and ICSKs. Inversion experiments are carried out with simple Gaussian-anomaly models and a complex Marmousi model. Overall, the parameterization of the P-wave velocity, S-wave velocity, and density, and the parameterization of the P-wave velocity, S-wave velocity, and S-wave impedance perform best for reconstructing all of the physical parameters. Isotropic-elastic FWI of the Hussar low-frequency data set with various model parameterizations verifies our conclusions.
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De la Sen, M., and A. Ibeas. "Stability Results of a Class of Hybrid Systems under Switched Continuous-Time and Discrete-Time Control." Discrete Dynamics in Nature and Society 2009 (2009): 1–28. http://dx.doi.org/10.1155/2009/315713.

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This paper investigates the stability properties of a class of switched systems possessing several linear time-invariant parameterizations (or configurations) which are governed by a switching law. It is assumed that the parameterizations are stabilized individually via an appropriate linear state or output feedback stabilizing controller whose existence is first discussed. A main novelty with respect to previous research is that the various individual parameterizations might be continuous-time, discrete-time, or mixed so that the whole switched system is a hybrid continuous/discrete dynamic system. The switching rule governs the choice of the parameterization which is active at each time interval in the switched system. Global asymptotic stability of the switched system is guaranteed for the case when a common Lyapunov function exists for all the individual parameterizations and the sampling period of the eventual discretized parameterizations taking part of the switched system is small enough. Some extensions are also investigated for controlled systems under decentralized or mixed centralized/decentralized control laws which stabilize each individual active parameterization.
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Dissertations / Theses on the topic "Parameterizations"

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Brück, Heiner Matthias. "Evaluation of statistical cloud parameterizations." Doctoral thesis, Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-212714.

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This work is motivated by the question: how much complexity is appropriate for a cloud parameterization used in general circulation models (GCM). To approach this question, cloud parameterizations across the complexity range are explored using general circulation models and theoretical Monte-Carlo simulations. Their results are compared with high-resolution satellite observations and simulations that resolve the GCM subgrid-scale variability explicitly. A process-orientated evaluation is facilitated by GCM forecast simulations which reproduce the synoptic state. For this purpose novel methods were develop to a) conceptually relate the underlying saturation deficit probability density function (PDF) with its saturated cloudy part, b) analytically compute the vertical integrated liquid water path (LWP) variability, c) diagnose the relevant PDF-moments from cloud parameterizations, d) derive high-resolution LWP from satellite observations and e) deduce the LWP statistics by aggregating the LWP onto boxes equivalent to the GCM grid size. On this basis, this work shows that it is possible to evaluate the sub-grid scale variability of cloud parameterizations in terms of cloud variables. Differences among the PDF types increase with complexity, in particular the more advanced cloud parameterizations can make use of their double Gaussian PDF in conditions, where cumulus convection forms a separate mode with respect to the remainder of the grid-box. Therefore, it is concluded that the difference between unimodal and bimodal PDFs is more important, than the shape within each mode. However, the simulations and their evaluation reveals that the advanced parameterizations do not take full advantage of their abilities and their statistical relationships are broadly similar to less complex PDF shapes, while the results from observations and cloud resolving simulations indicate even more complex distributions. Therefore, this work suggests that the use of less complex PDF shapes might yield a better trade-off. With increasing model resolution initial weaknesses of simpler, e.g. unimodal PDFs, will be diminished. While cloud schemes for coarse-resolved models need to parameterize multiple cloud regimes per grid-box, higher spatial resolution of future GCMs will separate them better, so that the unimodal approximation improves.
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Zagoruyko, Sergey. "Weight parameterizations in deep neural networks." Thesis, Paris Est, 2018. http://www.theses.fr/2018PESC1129/document.

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Les réseaux de neurones multicouches ont été proposés pour la première fois il y a plus de trois décennies, et diverses architectures et paramétrages ont été explorés depuis. Récemment, les unités de traitement graphique ont permis une formation très efficace sur les réseaux neuronaux et ont permis de former des réseaux beaucoup plus grands sur des ensembles de données plus importants, ce qui a considérablement amélioré le rendement dans diverses tâches d'apprentissage supervisé. Cependant, la généralisation est encore loin du niveau humain, et il est difficile de comprendre sur quoi sont basées les décisions prises. Pour améliorer la généralisation et la compréhension, nous réexaminons les problèmes de paramétrage du poids dans les réseaux neuronaux profonds. Nous identifions les problèmes les plus importants, à notre avis, dans les architectures modernes : la profondeur du réseau, l'efficacité des paramètres et l'apprentissage de tâches multiples en même temps, et nous essayons de les aborder dans cette thèse. Nous commençons par l'un des problèmes fondamentaux de la vision par ordinateur, le patch matching, et proposons d'utiliser des réseaux neuronaux convolutifs de différentes architectures pour le résoudre, au lieu de descripteurs manuels. Ensuite, nous abordons la tâche de détection d'objets, où un réseau devrait apprendre simultanément à prédire à la fois la classe de l'objet et l'emplacement. Dans les deux tâches, nous constatons que le nombre de paramètres dans le réseau est le principal facteur déterminant sa performance, et nous explorons ce phénomène dans les réseaux résiduels. Nos résultats montrent que leur motivation initiale, la formation de réseaux plus profonds pour de meilleures représentations, ne tient pas entièrement, et des réseaux plus larges avec moins de couches peuvent être aussi efficaces que des réseaux plus profonds avec le même nombre de paramètres. Dans l'ensemble, nous présentons une étude approfondie sur les architectures et les paramétrages de poids, ainsi que sur les moyens de transférer les connaissances entre elles
Multilayer neural networks were first proposed more than three decades ago, and various architectures and parameterizations were explored since. Recently, graphics processing units enabled very efficient neural network training, and allowed training much larger networks on larger datasets, dramatically improving performance on various supervised learning tasks. However, the generalization is still far from human level, and it is difficult to understand on what the decisions made are based. To improve on generalization and understanding we revisit the problems of weight parameterizations in deep neural networks. We identify the most important, to our mind, problems in modern architectures: network depth, parameter efficiency, and learning multiple tasks at the same time, and try to address them in this thesis. We start with one of the core problems of computer vision, patch matching, and propose to use convolutional neural networks of various architectures to solve it, instead of manual hand-crafting descriptors. Then, we address the task of object detection, where a network should simultaneously learn to both predict class of the object and the location. In both tasks we find that the number of parameters in the network is the major factor determining it's performance, and explore this phenomena in residual networks. Our findings show that their original motivation, training deeper networks for better representations, does not fully hold, and wider networks with less layers can be as effective as deeper with the same number of parameters. Overall, we present an extensive study on architectures and weight parameterizations, and ways of transferring knowledge between them
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Moon, Todd K., and Krishna Kishor Noru. "WAVEFORM SIGNAL SHAPING USING WAVELET PARAMETERIZATIONS." International Foundation for Telemetering, 2001. http://hdl.handle.net/10150/607582.

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International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada
We explore the idea of matching a scaling function - the basic building block of a wavelet function - to a desired spectrum. This would allow the scaling function to be used as the signal pulse for a digital communication system that is matched to the channel, avoiding problems such as energy loss or noise amplification due to spectral nulls. An unconstrained parameterization of the scaling function coefficients represents the scaling functions. This parameterization is adapted using gradient descent. Tests indicate that the adaptation is able to capture major features of a desired spectrum, including spectral nulls and major lobes.
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Hales, Jonathan Reid. "Divisors of Modular Parameterizations of Elliptic Curves." BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/8472.

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The modularity theorem implies that for every elliptic curve E /Q there exist rational maps from the modular curve X_0(N) to E, where N is the conductor of E. These maps may be expressed in terms of pairs of modular functions X(z) and Y(z) that satisfy the Weierstrass equation for E as well as a certain differential equation. Using these two relations, a recursive algorithm can be constructed to calculate the q - expansions of these parameterizations at any cusp. These functions are algebraic over Q(j(z)) and satisfy modular polynomials where each of the coefficient functions are rational functions in j(z). Using these functions, we determine the divisor of the parameterization and the preimage of rational points on E. We give a sufficient condition for when these preimages correspond to CM points on X_0(N). We also examine a connection between the algebras generated by these functions for related elliptic curves, and describe sufficient conditions to determine congruences in the q-expansions of these objects.
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Katz, Jeremy. "Evaluation of Surface Layer Parameterizations Using In-Situ Observations." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2604.

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Appropriate calculation of surface turbulent fluxes between the atmosphere and the underlying surface is one of the major challenges in geosciences. In practice, the surface turbulent fluxes are estimated from the mean surface meteorological variables based on the bulk transfer model combined with Monnin-Obukhov Similarity (MOS) theory. Few studies have been done to examine the extent that to which this flux parameterization framework can be applied to different weather and surface conditions. A novel validation method is developed in this thesis research, which is applied to evaluate the surface flux parameterization using in-situ observations. The main findings are: (a) the theoretical prediction that uses MOS theory does not match well with those directly computed from the observations collected in the coastal region. (b) Large spread in exchange coefficients mainly occurs in the calm wind regime with strong stability. (c) Large turbulent eddies, which depend largely on the mean flow and surface conditions, tend to break the constant flux assumption in the surface layer.
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Kim, Youngseob. "Air quality modeling : evaluation of chemical and meteorological parameterizations." Phd thesis, Université Paris-Est, 2011. http://pastel.archives-ouvertes.fr/pastel-00667777.

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The influence of chemical mechanisms and meteorological parameterizations on pollutant concentrations calculated with an air quality model is studied. The influence of the differences between two gas-phase chemical mechanisms on the formation of ozone and aerosols in Europe is low on average. For ozone, the large local differences are mainly due to the uncertainty associated with the kinetics of nitrogen monoxide (NO) oxidation reactions on the one hand and the representation of different pathways for the oxidation of aromatic compounds on the other hand. The aerosol concentrations are mainly influenced by the selection of all major precursors of secondary aerosols and the explicit treatment of chemical regimes corresponding to the nitrogen oxides (NOx) levels. The influence of the meteorological parameterizations on the concentrations of aerosols and their vertical distribution is evaluated over the Paris region in France by comparison to lidar data. The influence of the parameterization of the dynamics in the atmospheric boundary layer is important ; however, it is the use of an urban canopy model that improves significantly the modeling of the pollutant vertical distribution
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Quaas, Johannes, and Philip Stier. "Satellite observations of convection and their implications for parameterizations." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-203263.

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Parameterization development and evaluation ideally takes a two-step approach (Lohmann et al., 2007). Insight into new processes, and initial parameterization formulation should be guided by theory, process-level observations (laboratory experiments or field studies) or, if these are unavailable, by high-resolution modelling. However, once implemented into large-scale atmospheric models, a thorough testing and evaluation is required in order to assure that the parameterization works satisfactorily for all weather situations and at the scales the model is applied to. Satellite observations are probably the most valuable source of information for this purpose, since they offer a large range of parameters over comparatively long time series and with a very large, to global, coverage. However, satellites usually retrieve parameters in a rather indirect way, and some quantities (e.g., vertical wind velocities) are unavailable. It is thus essential for model evaluation 1. to assure comparability; and, 2. to develop and apply metrics that circumvent the limitations of satellite observations and help to learn about parameterizations. In terms of comparability, the implementation of so-called \"satellite simulators\" has emerged as the approach of choice, in which satellite retrievals are emulated, making use of model information about the subgrid-scale variability of clouds, and creating summary statistics (Bodas-Salcedo et al., 2011; Nam and Quaas, 2012; Nam et al., 2014). In terms of process-oriented metrics, a large range of approaches has been developed, e.g. investigating the life cycle of cirrus from convective detrainment (Gehlot and Quaas, 2012), or focusing on the details of microphysical processes (Suzuki et al., 2011). Besides such techniques focusing on individual parameterizations, the data assimilation technique might be exploited, by objectively adjusting convection parameters and learning about parameter choices and parameterizations in this way (Schirber et al., 2013).In this chapter, we will first introduce the available satellite data, consider their limitations and the approaches to account for these, and then discuss observations-based process-oriented metrics that have been developed so far.
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Griffin, Joshua Thomas. "Characterization of errors in various moisture roughness length parameterizations." Tallahassee, Florida : Florida State University, 2009. http://etd.lib.fsu.edu/theses/available/etd-11092009-112425/.

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Thesis (M.A.)--Florida State University, 2009.
Advisor: Mark A. Bourassa, Florida State University, College of Arts and Sciences, Dept. of Meteorology. Title and description from dissertation home page (viewed on Apr. 8, 2010). Document formatted into pages; contains viii, 30 pages. Includes bibliographical references.
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Wilkinson, Jonathan Mark. "Evaluating numerical model cloud parameterizations using radar and lidar simulation." Thesis, University of Reading, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440441.

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Solovev, Mikhail A. "Assessment of mesoscale eddy parameterizations for coarse resolution ocean models." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/58517.

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Thesis (Ph. D.)--Joint Program in Physical Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 1999.
Includes bibliographical references (p. 248-253).
Climate simulation with numerical oceanic models requires a proper parameterization scheme in order to represent the effects of unresolved mesoscale eddies. Even though a munber of schemes have been proposed and some have led to improvements in the simulation of the bulk climatological properties, the success of the parameterizations in representing the mesoscale eddies has not been investigated in detail. This thesis examines the role of eddies in a 105-years long basin scale eddy resolving simulation with the MIT General Circulation Model (GCM) forced by idealized wind stress and relaxation to prescribed meridional temperature; this thesis also evaluates the Fickian diffusive, the diabatic Green-Stone (GS) and the quasi-adiabatic Gent-McWilliams (GM) parameterizations in a diagnostic study and a series of coarse resolution experiments with the same model in the same configuration. The mesoscale eddies in the reference experiment provide a significant contribution to the thermal balance in limited areas of the domain associated with the upper 1000M of the boundary regions. Specifically designed diagnostic tests of the schemes show that the horizontal and vertical components of the parameterized flux are not simultaneously downgradient to the eddy heat flux. The transfer vectors are more closely aligned with the isopycnal surfaces for deeper layers, thus demonstrating the adiabatic nature of the eddy heat flux for deeper layers. The magnitude of the coefficients is estimated to be consistent with traditionally used values. However, the transfer of heat associated with timedependent motions is identified as a complicated process that cannot be fully explained with any of the local parameterization schemes considered. The eddy parameterization schemes are implemented in the coarse resolution configuration with the same model. A series of experiments exploring the schemes' parameter space demonstrate that Fickian diffusion has the least skill in the climatological simulations because it overestimates the temperature of the deep ocean and underestimates the total heat transport. The GS and GM schemes perform better in the simulation of the bulk climatological properties of the reference solution, although the GM scheme in particular produces an ocean that is consistently colder than the reference state. Comparison of the eddy heat flux divergence with the parameterized divergences for typical parameter values demonstrates that the success of the schemes in the climatological simulation is not related to the representation of the eddy heat flux but to the representation of the overall internal mixing processes.
by Mikhail A. Solovev.
Ph.D.
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Books on the topic "Parameterizations"

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1964-, Toro Tatiana, ed. Reifenberg parameterizations for sets with holes. Providence, R.I: American Mathematical Society, 2012.

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Cloud and precipitation microphysics: Principles and parameterizations. Cambridge: Cambridge University Press, 2009.

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Solovev, Mikhail A. Assessment of mesoscale eddy parameterizations for coarse resolution ocean models. Cambridge, Mass: Massachusetts Institute of Technology, 1999.

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Workshop on Cloud Microphysics Parameterizations in Global Atmospheric Circulation Models (1995 Kananaskis, Alta.). Workshop on Cloud Microphysics Parameterizations in Global Atmospheric Circulation Models: Kananaskis, Alberta, Canada, 23-25 May 1995. [Geneva, Switzerland: Joint Planning Staff for WCRP c/o World Meteorological Organization, 1995.

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Chassignet, Eric P., and Jacques Verron, eds. Ocean Modeling and Parameterization. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-5096-5.

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Chassignet, Eric P. Ocean Modeling and Parameterization. Dordrecht: Springer Netherlands, 1998.

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Ganchev, Todor. Contemporary Methods for Speech Parameterization. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-8447-0.

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Contemporary methods for speech parameterization. New York: Springer, 2011.

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Tripathi, Ram K. Universal parameterization of absorption cross sections. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1997.

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Tripathi, Ratikanta. Universal parameterization of absorption cross sections. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1997.

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Book chapters on the topic "Parameterizations"

1

Morawiec, Adam. "Parameterizations." In Orientations and Rotations, 19–49. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-662-09156-2_2.

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Poodiack, Robert D., and William E. Wood. "Parameterizations." In Springer Undergraduate Mathematics Series, 57–65. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-13783-9_7.

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Misra, Neeldhara. "Alternate Parameterizations." In Encyclopedia of Algorithms, 64–67. New York, NY: Springer New York, 2016. http://dx.doi.org/10.1007/978-1-4939-2864-4_786.

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Misra, Neeldhara. "Alternate Parameterizations." In Encyclopedia of Algorithms, 1–5. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-642-27848-8_786-1.

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Poodiack, Robert D., and William E. Wood. "Analytic parameterizations." In Springer Undergraduate Mathematics Series, 221–33. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-13783-9_20.

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Thiry, Louis, Long Li, and Etienne Mémin. "Modified (Hyper-)Viscosity for Coarse-Resolution Ocean Models." In Mathematics of Planet Earth, 273–85. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-18988-3_17.

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AbstractWe present a simple parameterization for coarse-resolution ocean models. To replace computationally expensive high-resolution ocean models, we develop a computationally cheap parameterization for coarse-resolution models based solely on the modification of the viscosity term in advection equations. It is meant to reproduce the mean quantities like pressure, velocity, or vorticity computed from a high-resolution reference solution or using observations. We test this new parameterization on a double-gyre quasi-geostrophic model in the eddy-permitting regime. Our results show that the proposed scheme improves significantly the energy statistics and the intrinsic variability on the coarse mesh. This method shall serve as a deterministic basis model for coarse-resolution stochastic parameterizations in future works.
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Uliasz, Marek. "Subgrid-Scale Parameterizations." In Mesoscale Modeling of the Atmosphere, 13–19. Boston, MA: American Meteorological Society, 1994. http://dx.doi.org/10.1007/978-1-935704-12-6_2.

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Bruhn, Henning, Morgan Chopin, Felix Joos, and Oliver Schaudt. "Structural Parameterizations for Boxicity." In Graph-Theoretic Concepts in Computer Science, 117–28. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-12340-0_10.

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Bailey, Barbara A., L. Mark Berliner, William Collins, Douglas W. Nychka, and Jeffrey T. Kiehl. "Neural Networks: Cloud Parameterizations." In Studies in the Atmospheric Sciences, 97–116. New York, NY: Springer New York, 2000. http://dx.doi.org/10.1007/978-1-4612-2112-8_7.

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Leclerc, Monique Y., and Thomas Foken. "Surface-Layer Properties and Parameterizations." In Footprints in Micrometeorology and Ecology, 21–70. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-54545-0_2.

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Conference papers on the topic "Parameterizations"

1

Bauchau, Olivier A., and Jou-Young Choi. "The Vectorial Parameterization of Motion." In ASME 2003 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/detc2003/vib-48304.

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This paper presents a vectorial parameterization of motion that generalizes the vectorial parameterization of rotation. The Pl¨ucker coordinates of an arbitrary material line of a rigid body subjected to a screw motion are shown to transform by the action of a motion tensor. The proposed vectorial parameterization completely describes an arbitrary motion by means of two vectors that constitute an eigenvector of the motion tensor associated with its positive unit eigenvalue. The first vector is conveniently selected as the vectorial parameterization of rotation, and the second is related to the displacement of a point of the rigid body. A complete description of motion is presented in terms of a generic vectorial parameterization. Relevant formulæ for specific parameterizations of this class can then be easily obtained. More details are given for three parameterizations that present desirable properties: the Euler, Cayley-Gibbs-Rodrigues, and Wiener-Milenkovic motion parameters.
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Eno, D. R., G. A. Young, and T. L. Sham. "A Unified View of Engineering Creep Parameters." In ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61129.

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Creep data are often analyzed using derived engineering parameters to correlate creep life (either time to rupture, or time to a specified strain) to applied stress and temperature. Commonly used formulations include Larson-Miller, Orr-Sherby-Dorn, Manson-Haferd, and Manson-Succop parameterizations. In this paper, it is shown that these parameterizations are all special cases of a common general framework based on a linear statistical model. Recognition of this fact allows for statistically efficient estimation of material model parameters and quantitative statistical comparisons among the various parameterizations in terms of their ability to fit a material database, including assessment of a stress-temperature interaction in creep behavior. This provides a rational basis for choosing the best parameterization to describe a particular material. Furthermore, using the technique of maximum likelihood estimation to estimate model parameters allows for a statistically proper treatment of runouts in a test database via censored data analysis methods, and for construction of probabilistically interpretable upper and lower bounds on creep rate. Comparisons are made to a generalization of the commonly used Larson-Miller parameterization (namely, the Mendelson-Roberts-Manson parameterization), which is comparable in complexity to the Manson-Haferd parameter, but utilizes a reciprocal temperature dependence. The general framework for analysis of creep data is illustrated with analysis of Alloy 617 and HAYNES® 230® alloy (Alloy 230) test data.
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Praun, Emil, Wim Sweldens, and Peter Schröder. "Consistent mesh parameterizations." In the 28th annual conference. New York, New York, USA: ACM Press, 2001. http://dx.doi.org/10.1145/383259.383277.

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Lina, Jean-Marc, and Michel Mayrand. "Parameterizations for complex Daubechies wavelets." In SPIE's International Symposium on Optical Engineering and Photonics in Aerospace Sensing, edited by Harold H. Szu. SPIE, 1994. http://dx.doi.org/10.1117/12.170087.

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Santos, Daniel Rodrigues, André Ricardo Fioravanti, Antonio Alberto Souza Santos, and Denis José Schiozer. "Investigation of Well Control Parameterization with Reduced Number of Variables Under Reservoir Uncertainties." In SPE Europec featured at 82nd EAGE Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/205207-ms.

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Abstract Although several studies have shown that life-cycle well control strategies can significantly improve a field's economic return, the industry often relies on short-term strategies. One drawback of traditional parameterization, adopted for well control life-cycle numerical optimization, is that it often generates control strategies that yield impractical abrupt changes in production curves. Another issue, especially in cases with a large number of decision variables, is the local optima convergence related to the non-convex optimization problems. In this context, we proposed and compared four life-cycle well control parameterizations to maximize the net present value (NPV) of the field under uncertainties, which are able to mitigate both the above-mentioned problems. The first parameterization optimizes the apportionment of well rates at the beginning of the field management and well shut-in time. The other three are based on optimizing the coefficients of parametric equations (first-and second-order polynomials, and logistic equation) to guide the bottom-hole pressure (BHP) over time. We executed each parameterization five times in a deterministic reservoir scenario and compared them with well control short-term strategy that prioritizes production in wells with higher oil-water ratio and that aimed to replicate the general industry practice. In this strategy, the wells’ priority rank was updated at every 30-simulation days. Subsequently, the best parameterization was used to select the well control life-cycle strategy under reservoir uncertainties and this strategy was applied to the reference model representing a real reservoir. The results showed that all the proposed parametrizations significantly improved the NPV in comparison to the well control short-term strategy, while simultaneously ensuring a smooth well production curve. The logistic equation presented the best result among all parameterizations, as it delivered both the highest average of NPV and the smallest dispersion over the five experiment repetitions. This parameterization also produced similar results when applied under uncertainties and for the reference model. These results endorse the importance of not only relying on a short-term strategy, but also planning it for the life-cycle.
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van Hoeij, Mark. "Computing parameterizations of rational algebraic curves." In the international symposium. New York, New York, USA: ACM Press, 1994. http://dx.doi.org/10.1145/190347.190415.

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Dong, Shen, and Michael Garland. "Iterative Methods for Improving Mesh Parameterizations." In IEEE International Conference on Shape Modeling and Applications 2007 (SMI '07). IEEE, 2007. http://dx.doi.org/10.1109/smi.2007.23.

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Grey, Zach, and Paul Constantine. "Active Subspaces of Airfoil Shape Parameterizations." In 58th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2017. http://dx.doi.org/10.2514/6.2017-0507.

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KENYON, RICHARD. "LIMIT SHAPES AND THEIR ANALYTIC PARAMETERIZATIONS." In International Congress of Mathematicians 2018. WORLD SCIENTIFIC, 2019. http://dx.doi.org/10.1142/9789813272880_0175.

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Wang, Yuh-Shyang, Nikolai Matni, and John C. Doyle. "System Level Parameterizations, constraints and synthesis." In 2017 American Control Conference (ACC). IEEE, 2017. http://dx.doi.org/10.23919/acc.2017.7963133.

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Reports on the topic "Parameterizations"

1

Jackson, Artie. Modified-Dewan Optical Turbulence Parameterizations. Fort Belvoir, VA: Defense Technical Information Center, June 2004. http://dx.doi.org/10.21236/ada432901.

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Teixeira, Joao. A Framework to Evaluate Unified Parameterizations for Seasonal Prediction: An LES/SCM Parameterization Test-Bed. Fort Belvoir, VA: Defense Technical Information Center, September 2012. http://dx.doi.org/10.21236/ada574019.

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Teixeira, Joao. A Framework to Evaluate Unified Parameterizations for Seasonal Prediction: An LES/SCM Parameterization Test-Bed. Fort Belvoir, VA: Defense Technical Information Center, September 2013. http://dx.doi.org/10.21236/ada598084.

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Hadzhilazova, Mariana, Ivaïlo Mladenov Ivaïlo Mladenov, and Peter Djondjorov. New Parameterizations of the Cassinian Ovals. GIQ, 2012. http://dx.doi.org/10.7546/giq-12-2011-237-243.

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Goodman, Louis. Development of Turbulent Biological Closure Parameterizations. Fort Belvoir, VA: Defense Technical Information Center, January 2008. http://dx.doi.org/10.21236/ada505108.

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Goodman, Louis. Development of Turbulent Biological Closure Parameterizations. Fort Belvoir, VA: Defense Technical Information Center, September 2011. http://dx.doi.org/10.21236/ada598069.

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Lovell, Amy Elizabeth, Patrick Talou, Ionel Stetcu, Arvind Thanam Mohan, and Michael Chertkov. Constructing Global Fission Yield Parameterizations for CGMF. Office of Scientific and Technical Information (OSTI), December 2018. http://dx.doi.org/10.2172/1487353.

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Gregg, Michael C., and Jack Miller. Flow Over Difficult Bathymetry: Processes and Parameterizations. Fort Belvoir, VA: Defense Technical Information Center, October 2003. http://dx.doi.org/10.21236/ada418045.

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Bruce Albrecht. Boundary Layer Cloudiness Parameterizations Using ARM Observations. Office of Scientific and Technical Information (OSTI), September 2004. http://dx.doi.org/10.2172/830034.

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Gregg, Michael C., and Parker MacCready. Flow over Difficulty Bathymetry: Processes and Parameterizations. Fort Belvoir, VA: Defense Technical Information Center, September 2001. http://dx.doi.org/10.21236/ada624733.

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