A Sensitivity Research of Numerical Simulation about Winter Sea-Land Breeze

2013 ◽  
Vol 380-384 ◽  
pp. 1800-1803
Author(s):  
Xiao Lan Tang ◽  
Shui Yuan Cheng
Keyword(s):  
Numerical Simulation ◽  
Wind Field ◽  
Wrf Model ◽  
Horizontal Resolution ◽  
Land Breeze ◽  
Threshold Values ◽  
Tropical Island ◽  
Wind Field Simulation ◽  
Field Simulation ◽  
The Impact

Using the WRF model and NCEP data, a typical winter sea-land breeze progress in China tropical island was simulated, analyzing the impact of wind field simulation with the horizontal resolution, analog range, nesting level, and analog time. The results showed: the simulate effects of the WRF model could not always keep step with the increase of horizontal resolution. Obviously there was a threshold for the model horizontal resolution. By the same token, analog range, nesting level, and analog time have its threshold. The accuracy of the simulation reduced when the threshold values were exceeded.

The Effects of Vertical Stratification and Land Use Data on Numerical Simulation of Wind Energy Resources

2014 ◽  
Vol 535 ◽  
pp. 135-140
Author(s):  
Yuan Chang Deng ◽  
Zhen Cao Zou
Keyword(s):  
Numerical Simulation ◽  
Land Use ◽  
Wind Field ◽  
Wind Profile ◽  
Surface Wind ◽  
Wrf Model ◽  
Vertical Stratification ◽  
Near Surface ◽  
Wind Field Simulation ◽  
Surface Wind Field

By adjusting the distribution of vertical layers and increasing its number in WRF model, this paper mainly studies the effects of vertical stratification on the near surface wind field and vertical profile simulation. The test outcomes show that moderately increasing vertical layers can effectively improve the near surface wind field simulation results, while it has little influence on the numeral and changing trend of high vertical wind profile. Considering both accuracy and efficiency, it is recommended to set 10~15 layers below 300m. On the basis of this research, instead of USGS data by using the MODIS_30S data, the data underlying surface land in Shenzhen and HK area are updated. Comparative results between the two schemes, due to the roughness and drag coefficient of difference types of surface are not identical; the surface data has a significant impact on wind field and wind profile simulation. Using the MODIS land use data which is more consistent with the actual situation can improve the accuracy of numerical simulation.

Three-Dimensional Wind Field Simulation on the Two Typical Roofs of the Building

2014 ◽  
Vol 986-987 ◽  
pp. 685-688
Author(s):  
Shu Qin Liu ◽  
Zhong Guo Bian ◽  
Yuan Bo Cai ◽  
Fang Zhao
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Wind Energy ◽  
Wind Field ◽  
Three Dimensional ◽  
Simulation Method ◽  
Energy Utilization ◽  
Wind Field Simulation ◽  
Field Simulation ◽  
Important Significance

Wind energy utilization in the building environment has the advantage that it can avoid transporting effectively, especially it has important significance for residents without electricity. This paper mainly analyzed the basic situation of three-dimensional wind field around the buildings with the theoretical analysis and CFD numerical simulation method. By simulating the wind with different directions and different speeds, the characteristics of the wind field around single flat and pitched roof building are analyzed.

scholarly journals A Case Study of Observed and Modeled Barrier Flow in the Denmark Strait in May 2015

2017 ◽  
Vol 145 (6) ◽  
pp. 2385-2404 ◽  
Author(s):  
Alice K. DuVivier ◽  
John J. Cassano ◽  
Steven Greco ◽  
G. David Emmitt
Keyword(s):  
Wrf Model ◽  
Horizontal Resolution ◽  
Surface Energy Budget ◽  
Vertical Resolution ◽  
Structure Comparison ◽  
Denmark Strait ◽  
Pbl Scheme ◽  
Barrier Jets ◽  
The Impact ◽  
Jet Structure

Abstract Mesoscale barrier jets in the Denmark Strait are common in winter months and have the capability to influence open ocean convection. This paper presents the first detailed observational study of a summertime (21 May 2015) barrier wind event in the Denmark Strait using dropsondes and observations from an airborne Doppler wind lidar (DWL). The DWL profiles agree well with dropsonde observations and show a vertically narrow (~250–400 m) barrier jet of 23–28 m s−1 near the Greenland coast that broadens (~300–1000 m) and strengthens farther off coast. In addition, otherwise identical regional high-resolution Weather Research and Forecasting (WRF) Model simulations of the event are analyzed at four horizontal grid spacings (5, 10, 25, and 50 km), two vertical resolutions (40 and 60 levels), and two planetary boundary layer (PBL) parameterizations [Mellor–Yamada–Nakanishi–Niino, version 2.5 (MYNN2.5) and University of Washington (UW)] to determine what model configurations best simulate the observed jet structure. Comparison of the WRF simulations with wind observations from satellites, dropsondes, and the airborne DWL scans indicate that the combination of both high horizontal resolution (5 km) and vertical resolution (60 levels) best captures observed barrier jet structure and speeds as well as the observed cloud field, including some convective clouds. Both WRF PBL schemes produced reasonable barrier jets with the UW scheme slightly outperforming the MYNN2.5 scheme. However, further investigation at high horizontal and vertical resolution is needed to determine the impact of the WRF PBL scheme on surface energy budget terms, particularly in the high-latitude maritime environment around Greenland.

Fog forecasting for Schiphol airport at sub-kilometre scale.  

2021 ◽  
Author(s):  
Gert-Jan Steeneveld ◽  
Roosmarijn Knol
Keyword(s):  
Spatial Resolution ◽  
Numerical Models ◽  
Wrf Model ◽  
Horizontal Resolution ◽  
Physical Processes ◽  
Radiation Fog ◽  
Fog Forecasting ◽  
Elevation Data ◽  
The Individual ◽  
The Impact

<p>Fog is a critical weather phenomenon for safety and operations in aviation. Unfortunately, the forecasting of radiation fog remains challenging due to the numerous physical processes that play a role and their complex interactions, in addition to the vertical and horizontal resolution of the numerical models. In this study we evaluate the performance of the Weather Research and Forecasting (WRF) model for a radiation fog event at Schiphol Amsterdam Airport (The Netherlands) and further develop the model towards a 100 m grid spacing. Hence we introduce high resolution land use and land elevation data. In addition we study the role of gravitational droplet settling, advection of TKE, top-down diffusion caused by strong radiative cooling at the fog top. Finally the impact of heat released by the terminal areas on the fog formation is studied. The model outcomes are evaluated against 1-min weather observations near multiple runways at the airport.</p><p>Overall we find the WRF model shows an reasonable timing of the fog onset and is well able to reproduce the visibility and meteorological conditions as observed during the case study. The model appears to be relatively insensitive to the activation of the individual physical processes. An increased spatial resolution to 100 m generally results in a better timing of the fog onset differences up to three hours, though not for all runways. The effect of the refined landuse dominates over the effect of refined elevation data. The modelled fog dissipation systematically occurs 3-4 h hours too early, regardless of physical processes or spatial resolution. Finally, the introduction of heat from terminal buildings delays the fog onset with a maximum of two hours, an overestimated visibility of 100-200 m and a decrease of the LWC with 0.10-0.15 g/kg compared to the reference.</p>

The European wind from observational and simulated databases

2020 ◽  
Author(s):  
Elena García-Bustamante ◽  
Jorge Navarro ◽  
Jesús Fidel González-Rouco ◽  
E. Etor Lucio- Eceiza ◽  
Cristina Rojas-Labanda ◽  
...  
Keyword(s):  
Wind Field ◽  
Mesoscale Model ◽  
Surface Wind ◽  
Wrf Model ◽  
Horizontal Resolution ◽  
Spatial And Temporal Variability ◽  
Model Simulations ◽  
Wind Variability ◽  
Observational Database ◽  
Wind Velocities

<p>The New European Wind Atlas (https://map.neweuropeanwindatlas.eu) is developed based on the simulated wind field over Europe from a mesoscale model coupled to a microscale component through a statistical downscaling approach. The simulation that provides mesoscale inputs within the model chain has been decided upon a careful sensitivity analysis of potential model configurations. In order to accomplish model resolutions of 3 km over Europe, the broader European domain is partitioned into a set of 10 partially overlapping tiles. The wind field is simulated with the WRF model over these tiles and finally blended into a single domain. The wind outputs from a reference simulation is evaluated on the basis of its comparison with an observational database specifically compiled and quality controlled for the purpose of validating the wind atlas over the complete European domain. The observational database includes surface wind observations at ca. 4000 sites as well as 16 masts datasets. The observational dataset of surface wind (WISED) is informative about the spatial and temporal variability of the wind climatology, punctuated with singular masts that provide information of wind velocities at height. The validation of the mesoscale simulation aims at investigating the ability of the high-resolution simulation to reproduce the observed intra-annual variability of daily wind within the entire domain.</p><p>Observed and simulated winds are higher at the British, North Sea and Baltic shores and lowlands. Correlations are typically over 0.8. Surface wind variability tends to be overestimated in the northern coasts and underestimated elsewhere and inland. Mast wind variability tends to be overestimated except for some southern sites. Seasonal differences seem minor in these respects. Biases and RMSE can help identifying if systematic errors in specific tiles take place.</p><p>Therefore, performing model simulations of a high horizontal resolution over the broader European domain is possible. We can learn about the variability of surface and height wind both from observations and model simulations. Model observations are not perfect, but observations also present uncertainties. Good quality wind data, both at the surface and in masts are a requisite for robust evaluation of models. European wide features of wind variability can be recognized both in observations and simulations.</p>

scholarly journals Impact of optimized mixing heights on simulated regional atmospheric transport of CO<sub>2</sub>

2014 ◽  
Vol 14 (14) ◽  
pp. 7149-7172 ◽  
Author(s):  
R. Kretschmer ◽  
C. Gerbig ◽  
U. Karstens ◽  
G. Biavati ◽  
A. Vermeulen ◽  
...  
Keyword(s):  
Dispersion Model ◽  
Synthetic Data ◽  
Wrf Model ◽  
Horizontal Resolution ◽  
Particle Dispersion ◽  
Random Errors ◽  
Tracer Transport ◽  
European Continent ◽  
Co2 Transport ◽  
The Impact

Abstract. The mixing height (MH) is a crucial parameter in commonly used transport models that proportionally affects air concentrations of trace gases with sources/sinks near the ground and on diurnal scales. Past synthetic data experiments indicated the possibility to improve tracer transport by minimizing errors of simulated MHs. In this paper we evaluate a method to constrain the Lagrangian particle dispersion model STILT (Stochastic Time-Inverted Lagrangian Transport) with MH diagnosed from radiosonde profiles using a bulk Richardson method. The same method was used to obtain hourly MHs for the period September/October 2009 from the Weather Research and Forecasting (WRF) model, which covers the European continent at 10 km horizontal resolution. Kriging with external drift (KED) was applied to estimate optimized MHs from observed and modelled MHs, which were used as input for STILT to assess the impact on CO2 transport. Special care has been taken to account for uncertainty in MH retrieval in this estimation process. MHs and CO2 concentrations were compared to vertical profiles from aircraft in situ data. We put an emphasis on testing the consistency of estimated MHs to observed vertical mixing of CO2. Modelled CO2 was also compared with continuous measurements made at Cabauw and Heidelberg stations. WRF MHs were significantly biased by ~10–20% during day and ~40–60% during night. Optimized MHs reduced this bias to ~5% with additional slight improvements in random errors. The KED MHs were generally more consistent with observed CO2 mixing. The use of optimized MHs had in general a favourable impact on CO2 transport, with bias reductions of 5–45% (day) and 60–90% (night). This indicates that a large part of the found CO2 model–data mismatch was indeed due to MH errors. Other causes for CO2 mismatch are discussed. Applicability of our method is discussed in the context of CO2 inversions at regional scales.

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