scholarly journals Review of Wind Models at a Local Scale: Advantages and Disadvantages

2021 ◽  
Vol 9 (3) ◽  
pp. 318
Author(s):  
Felix P. Martinez-García ◽  
Antonio Contreras-de-Villar ◽  
Juan J. Muñoz-Perez
Keyword(s):  
Large Scale ◽  
Near Field ◽  
Wind Farms ◽  
Local Scale ◽  
Data Driven ◽  
Future Scenarios ◽  
Global Circulation ◽  
Advantages And Disadvantages ◽  
Global Circulation Models

Wind forecasts are widely spread because of the growth in wind power, but also because there are other applications to consider, such as the long-term scenario forecasts regarding the effects of global warming. Overall, there have been big developments in global circulation models (GCM) that inform future scenarios at the large scale, but wind forecast at a local scale is a problem that has not totally been solved. It should be possible to estimate the winds in the near field with a certain accuracy, which is interesting for aspects such as the blowing of incident wind at wind farms, the wind on a dune in movement, or the wind blowing in a harbour. Therefore, a data-driven wind transference equation at a local scale is needed. Among the conclusions, it is worthy to state that the statistical downscaling techniques are suitable for application as a statistical inference at small scales. The aim of this paper is therefore to review the current methods and techniques used and show the different methodologies and their applications in the field. Additional targets will be to identify the advantages, disadvantages, or limitations of the current models at the local scale and propose research to find possible improvements.

scholarly journals Comparison and assessment of large-scale surface temperature in climate model simulations

2019 ◽  
Vol 5 (1) ◽  
pp. 67-85
Author(s):  
Raquel Barata ◽  
Raquel Prado ◽  
Bruno Sansó
Keyword(s):  
Surface Temperature ◽  
Seasonal Changes ◽  
Large Scale ◽  
Climate Model ◽  
Internal Variability ◽  
Temperature Variability ◽  
Data Driven ◽  
Model Simulations ◽  
Climate Model Simulations

Abstract. We present a data-driven approach to assess and compare the behavior of large-scale spatial averages of surface temperature in climate model simulations and in observational products. We rely on univariate and multivariate dynamic linear model (DLM) techniques to estimate both long-term and seasonal changes in temperature. The residuals from the DLM analyses capture the internal variability of the climate system and exhibit complex temporal autocorrelation structure. To characterize this internal variability, we explore the structure of these residuals using univariate and multivariate autoregressive (AR) models. As a proof of concept that can easily be extended to other climate models, we apply our approach to one particular climate model (MIROC5). Our results illustrate model versus data differences in both long-term and seasonal changes in temperature. Despite differences in the underlying factors contributing to variability, the different types of simulation yield very similar spectral estimates of internal temperature variability. In general, we find that there is no evidence that the MIROC5 model systematically underestimates the amplitude of observed surface temperature variability on multi-decadal timescales – a finding that has considerable relevance regarding efforts to identify anthropogenic “fingerprints” in observational surface temperature data. Our methodology and results present a novel approach to obtaining data-driven estimates of climate variability for purposes of model evaluation.

scholarly journals Review of effective emissions modeling and computation

2011 ◽  
Vol 4 (3) ◽  
pp. 643-667 ◽  
Author(s):  
R. Paoli ◽  
D. Cariolle ◽  
R. Sausen
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Reaction Rates ◽  
Transport Models ◽  
Global Circulation ◽  
Global Circulation Models ◽  
Emissions Modeling ◽  
Exhaust Plumes ◽  
Physical And Chemical ◽  
Scale Grid

Abstract. An important issue in the evaluation of the environmental impact of emissions from concentrated sources such as transport modes, is to understand how processes occurring at the scales of exhaust plumes can influence the physical and chemical state of the atmosphere at regional and global scales. Indeed, three-dimensional global circulation models or chemistry transport models generally assume that emissions are instantaneously diluted into large-scale grid boxes, which may lead, for example, to overpredict the efficiency of NOx to produce ozone. In recent times, various methods have been developed to incorporate parameterizations of plume processes into global models that are based e.g. on correcting the original emission indexes or on introducing "subgrid" reaction rates in the models. This paper provides a review of the techniques proposed so far in the literature to account for local conversion of emissions in the plume, as well as the implementation of these techniques into atmospheric codes.

scholarly journals Spatial Coherence of Monsoon Onset over Western and Central Sahel (1950–2000)

2009 ◽  
Vol 22 (5) ◽  
pp. 1313-1324 ◽  
Author(s):  
Romain Marteau ◽  
Vincent Moron ◽  
Nathalie Philippon
Keyword(s):  
Burkina Faso ◽  
Interannual Variability ◽  
Large Scale ◽  
Spatial Coherence ◽  
Daily Rainfall ◽  
Local Scale ◽  
Monsoon Onset ◽  
Onset Date ◽  
Dry Spell

Abstract The spatial coherence of boreal monsoon onset over the western and central Sahel (Senegal, Mali, Burkina Faso) is studied through the analysis of daily rainfall data for 103 stations from 1950 to 2000. Onset date is defined using a local agronomic definition, that is, the first wet day (>1 mm) of 1 or 2 consecutive days receiving at least 20 mm without a 7-day dry spell receiving less than 5 mm in the following 20 days. Changing either the length or the amplitude of the initial wet spell, or both, or the length of the following dry spell modifies the long-term mean of local-scale onset date but has only a weak impact either on its interannual variability or its spatial coherence. Onset date exhibits a seasonal progression from southern Burkina Faso (mid-May) to northwestern Senegal and Saharian edges (early August). Interannual variability of the local-scale onset date does not seem to be strongly spatially coherent. The amount of common or covariant signal across the stations is far weaker than the interstation noise at the interannual time scale. In particular, a systematic spatially consistent advance or delay of the onset is hardly observed across the whole western and central Sahel. In consequence, the seasonal predictability of local-scale onset over the western and central Sahel associated, for example, with large-scale sea surface temperatures, is, at best, weak.

scholarly journals The use of relaxation methods in the WRF model for the analysis of meteorological conditions in Ukraine over a long period

2020 ◽  
Vol 2 ◽  
pp. 30-42
Author(s):  
O.V. Khalchenkov ◽  
◽  
I.V. Kovalets ◽  
Keyword(s):  
Large Scale ◽  
Mesoscale Model ◽  
Soil Layer ◽  
Meteorological Conditions ◽  
Optimal Combination ◽  
Relaxation Methods ◽  
Advantages And Disadvantages ◽  
Long Period ◽  
Surface Measurements

The possibility of using grid and spectral relaxation methods and other options in the WRF mesoscale model for long-term continuous calculations has been investigated. Results of comparison of selected me-teorological parameters with surface measurements are presented. The basic recommendations for select-ing the optimal combination of long-term calculation parameters are given. The use of the selected param-eters allowed to obtain continuous meteorological fields over a long period (several months), which are well consistent with surface measurements, retain large scale synoptic structures and have a deviation from measurements commensurate with the results of short-term simulations over corresponding time peri-od. The selected optimal combination of parameters allowed us to perform continuous calculation for the period from January 1, 2019 to November 6, 2019 without accumulating errors. In a long-run calculation of meteorological conditions in Ukraine with spatial resolution 0.15 deg. for a temperature at a height of 2 meters was obtained a mean absolute error of MAE=2,05 ºC, a correlation coefficient of Corr=0,97, for a wind speed at a height of 10 meters of MAE=1.4 m/s, of Corr=0,75, and for a wind direction at a height of 10 meters of MAE=24,6 degrees, Corr=0,66. The influence of the parametrizations of the underlying sur-face and the active soil layer on the quality of calculation of meteorological fields is studied. Using the option to update the water surface temperature allowed to reduce the MAE for the temperature from 2,17 ºС to 2,05 ºС. Each of the investigated surface models showed its advantages and disadvantages. The pa-rameterizations RUC and NOAH LSM showed good agreement with the measurements for all studied pa-rameters and can be recommended for use in long-term continuous calculations. A long calculation made it possible to describe the process of accumulation and melting of snow correctly, and made it possible to reproduce the temperature of the upper soil layer correctly as well. The paper shows that the disadvantage of long- term calculations is the inability to determine the temperature of the lower layers of the soil cor-rectly.

A Review of Downhole Wireless Technologies and Improvements

2021 ◽  
Author(s):  
Brett Bouldin ◽  
Ahmed AlShmakhy ◽  
Ahmed Khaled Bazuhair ◽  
Muzoon Hasan Alzaabi ◽  
Jarl André Fellinghaug
Keyword(s):  
Wireless Communication ◽  
Flow Rate ◽  
Large Scale ◽  
Pressure Pulse ◽  
Cost Effective ◽  
Directional Drilling ◽  
Wireless Technologies ◽  
Advantages And Disadvantages ◽  
Wireless Telemetry

Abstract Downhole wireless communication in the form of mud pulse telemetry enabled directional drilling over the past 60 years and has been hugely successful. Technologies like Measurement While Drilling (MWD), Logging While Drilling (LWD), and Geosteering would simply not exist without it. But in the Production and Producing end of the business, applications for downhole wireless communication have been less clear, especially where long distances and long-term monitoring are concerned. Several wireless technologies are in use today for long-term production applications. Electromagnetic (EM), acoustic, and pressure pulse telemetries are finding application as wireless production gauges, drill stem test tools, and drilling alternatives to pressure pulse. But the large-scale vision of, "Breaking the Wire!" in production wells has not yet occurred. Permanent Downhole Gauges (PDG) with an umbilical to surface are still the product of choice for long-term production monitoring. A history of wireless approaches in production applications will be given and the different methods used in the industry will be explained. A comparison and contrast of wireless telemetry methods will be explored, explained, and evaluated. Advantages and disadvantages will be listed for each approach. A ranking system will be employed to illustrate the evaluation results of the different wireless telemetry methods. New variants for wireless telemetry, power supplies, and measurement methods will be proposed. Preferred applications for each gauge type will be given. Downhole gauges can be improved by integrating pressure pulse, a downhole power generator, and downhole flow rate measurement into a single unit. The overall size can be ten times shorter than existing systems while still generating a larger wireless signal. Such a system would make wireless downhole gauges much more practical and should significantly increase their uptake in the industry. Real-time measurement of downhole pressure and downhole flow rate transforms the accuracy and effectiveness of Pressure Transient Analysis (PTA). Better reservoir understanding can be gained by using only drawdown tests, without shutting in the well. Smaller tools are generally more cost effective.

scholarly journals Using the UM dynamical cores to reproduce idealised 3-D flows

2014 ◽  
Vol 7 (6) ◽  
pp. 3059-3087 ◽  
Author(s):  
N. J. Mayne ◽  
I. Baraffe ◽  
D. M. Acreman ◽  
C. Smith ◽  
N. Wood ◽  
...  
Keyword(s):  
Large Scale ◽  
Circulation Model ◽  
Simplified Model ◽  
Global Circulation Model ◽  
Dynamical Equations ◽  
Present Evidence ◽  
Global Circulation ◽  
The Uk ◽  
Tidally Locked Earth

Abstract. We demonstrate that both the current (New Dynamics), and next generation (ENDGame) dynamical cores of the UK Met Office global circulation model, the UM, reproduce consistently, the long-term, large-scale flows found in several published idealised tests. The cases presented are the Held–Suarez test, a simplified model of Earth (including a stratosphere), and a hypothetical tidally locked Earth. Furthermore, we show that using simplifications to the dynamical equations, which are expected to be justified for the physical domains and flow regimes we have studied, and which are supported by the ENDGame dynamical core, also produces matching long-term, large-scale flows. Finally, we present evidence for differences in the detail of the planetary flows and circulations resulting from improvements in the ENDGame formulation over New Dynamics.

scholarly journals Using the UM dynamical cores to reproduce idealised 3-D flows

2013 ◽  
Vol 6 (3) ◽  
pp. 3681-3741 ◽  
Author(s):  
N. J. Mayne ◽  
I. Baraffe ◽  
D. M. Acreman ◽  
C. Smith ◽  
N. Wood ◽  
...  
Keyword(s):  
Large Scale ◽  
Circulation Model ◽  
Test Case ◽  
Global Circulation Model ◽  
Dynamical Equations ◽  
Present Evidence ◽  
Global Circulation ◽  
The Uk ◽  
Tidally Locked Earth

Abstract. We demonstrate that both the current (New Dynamics), and next generation (ENDGame) dynamical cores of the UK Met Office global circulation model, the UM, reproduce consistently, the long-term, large-scale flows found in several published idealised tests. The cases presented are the Held–Suarez test, a simplified model of Earth (including a stratosphere), and a model of a hypothetical Tidally Locked Earth (TLE). Furthermore, we show that using simplifications to the dynamical equations, which are expected to be justified for the physical domains and flow regimes we have studied, and which are supported by the ENDGame dynamical core, also produces matching long-term, large-scale flows. Finally, we present evidence for differences in the detail of the planetary (meridional) flows and circulations resulting from improvements in the ENDGame formulation over New Dynamics. Specifically, we find greater symmetry in the meridional circulations of the Tidally Locked Earth test case using the ENDGame formulation, which is a better match to our physical expectations of the flow for such a slowly rotating Earth-like system.

scholarly journals Modeling and computation of effective emissions: a position paper

2011 ◽  
Vol 4 (1) ◽  
pp. 137-196 ◽  
Author(s):  
R. Paoli ◽  
D. Cariolle ◽  
R. Sausen
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Reaction Rates ◽  
Position Paper ◽  
Transport Models ◽  
Global Circulation ◽  
Global Circulation Models ◽  
Exhaust Plumes ◽  
Physical And Chemical ◽  
Scale Grid

Abstract. An important issue in the evaluation of the environmental impact of emissions from concentrated sources such as transport modes, is to understand how processes occurring at the scales of exhaust plumes can influence the physical and chemical state of the atmosphere at regional and global scales. Indeed, three-dimensional global circulation models or chemistry transport models generally assume that emissions are instantaneously diluted into large-scale grid boxes, which may lead, for example, to overpredict the efficiency of NOx to produce ozone. In recent times, various methods have been developed to incorporate parameterizations of plume processes into global models that are based either on the correction of the original emissions or on the introduction of subgrid reaction rates in the models. This paper provides a review of the techniques proposed so far in the literature to account for local conversion of emissions in the plume, as well as the implementation of these techniques into atmospheric codes.

Mooring Designs for Floating Offshore Wind Turbines Leveraging Experience From the Oil & Gas Industry

2021 ◽  
Author(s):  
Kai-tung Ma ◽  
Yongyan Wu ◽  
Simen Fodstad Stolen ◽  
Leopoldo Bello ◽  
Menno ver der Horst ◽  
...  
Keyword(s):  
Wind Turbines ◽  
Large Scale ◽  
Wind Farms ◽  
Offshore Wind ◽  
Synthetic Fiber ◽  
Extensive Experience ◽  
Gas Industry ◽  
Offshore Wind Turbines ◽  
Floating Offshore Wind Turbines

Abstract As renewable energy developers start venturing into deeper waters, the floating offshore wind turbines (FOWTs) are becoming the preferred solutions over fixed supporting structures. Many similarities can be identified between a FOWT and a floating oil & gas facility, such as floater concepts (spar, semi-submersible, tension leg platform, etc) and their mooring system designs. This paper focuses on the mooring designs for FOWTs by leveraging the extensive experience gained from the offshore oil & gas industry. Similarities and differences are highlighted in design criteria, mooring analysis, long-term integrity management, installation method and project execution. The established practices regarding mooring design and analysis are reviewed. Anchor radius is recommended based on water depth by referencing sample mooring designs from the oil & gas industry. Long-term mooring integrity and failure rates are summarized. Meanwhile, a few well-known issues are discussed, such as line break due to fatigue, corrosion on chain, and known issues with components such as clump weights. Regarding mooring installation, the established method for prelay and hook-up is reviewed. Finally, opportunities for cost reduction of mooring systems of FOWTs are presented related to project execution of large scale wind farms as well as potential areas of innovation, such as installation methods, use of synthetic fiber rope, and digitalization. In summary, the state-of-the-art practices from the oil & gas industry are reviewed and documented to benefit the developments of upcoming FOWT projects.

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