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1.
基于WRF和CFD软件结合的风能资源数值模拟试验研究 总被引：4，自引：2，他引：2
运用中尺度数值模式WRF与法国CFD软件MeteodynwT相结合的方法（WRF／WT）,进行了广东省海陵岛地区的水平分辨率100m×100m的风能资源数值模拟试验,采用海陵岛上7座测风塔观测资料对WRF／WT模式的模拟风场进行误差检验,并与WRF／WAsP模式系统对单点风能参数模拟误差进行对比,研究WRF／WT模式系统在风电场微观选址和分散式风电开发利用中应用的可行性。结果表明：中尺度模式与CFD软件结合的数值模拟方法对区域风能资源分布趋势的模拟比单纯应用CFD软件更准确;WRF／WT模式系统应用于复杂地形风能资源数值模拟评估是可行的,其对区域风能资源参数分布模拟的准确率与WRF／WAsP对2km范围内风能资源参数模拟的准确率相当;WRF／WT模式系统在风速频率分布不满足Weibull分布的情况下和陡峭地形条件下有较好的模拟效果,相对WRF／wAsP有明显优势。今后需进一步研究中尺度模式与CFD软件的衔接方法,以及对中尺度模式模拟结果的误差订正。 相似文献
2.
Discussed are the results of studying an evolution of tropical cyclones (TCs) in the Pacific Ocean using the data of computation of ETA and WRF NMM mesoscale numerical atmospheric models. Computed are the trajectories of TCs and the fields of meteorological variables in the typhoons, of the wind speed and kinetic energy in the subtropical jet stream during the development of Parma, Melor, and Lupit typhoons. Carried out are the analysis and comparison of computed fields of pressure, wind, kinetic energy, and trajectories of TCs obtained using these models and their comparison with the actual fields. It is demonstrated that both models computed rather well the complex trajectories and the fields of wind and kinetic energy varying in the course of the interaction. Proposed is an explanation of processes taking place during the interaction between the vortices and the subtropical jet stream and the polar front. 相似文献
3.
复杂地形风场的精细数值模拟 总被引：1，自引：0，他引：1
风能是一种重要气候资源,随着我国风电规模的迅速增大,发展风能资源评估系统和风功率预测系统已成为一项重要的研究内容。国内外对复杂地形风场结构的数值模拟有大量研究,随着计算机能力增强,以往用于空气动力学精细流场计算的计算流体力学(Computational Fluid Dynamics,CFD)模式越来越多地在气象领域得到应用,人们开始研究用中尺度预报模式和CFD模式结合进行复杂地形风场的数值模拟。本文的耦合模式系统采用中尺度气象模式(WRF),通过嵌套网格到内层尺度(一般是几公里),然后通过耦合CFD模式Fluent软件获得高分辨率(水平30~100 m,垂直150 m高度以下10 m)的风速分布资料,得到精细化的风场信息。通过对鄱阳湖北部区域和云南杨梅山复杂地形的风场模拟,提供了风能评估和预报的一种可行的方法。 相似文献
4.
正压大气中尺度半平衡和准平衡动力学模式 总被引：3，自引：0，他引：3
应用描写正压大气运动的基本方程组，分析了中尺度大气运动的物理特征，指出非平衡强迫运动是引起中尺度重要天气演变的根本原因。中尺度动力学方程组是中尺度动力学理论研究的基础，因此，结合中尺度大气运动的基本特征，依据严格的尺度分析理论和摄动理论，简化基于流体力学和热力学的大气动力学方程组使之能够恰当地描述出中尺度运动的基本特征，对于中尺度动力学的发展是极为必要的。基于非线性平衡方程所得到的半平衡和准平衡动力学模式分别与半地转和准地转模式极为相似，它们可以较精确地描述中尺度大气运动的基本特征，因而，可作为中尺度动力学研究的理论基础。将准平衡动力学模式应用于中尺度涡旋系统的研究，结论表明中尺度平衡涡旋系统主要是受梯度风控制，其流场和气压场的发展演变则由一个演化方程来描写，获得了较为理想的结果。 相似文献
5.
Vertical heat fluxes induced by mesoscale thermally driven circulations maycontribute significantly to the subgrid-scale fluxes in large-scale models (e.g.,general circulation models). However, they are not considered in these modelsyet. To gain insight into the importance and possible parameterisation of themesoscale flux associated with slope winds, an analytical (conceptual) modelis developed to describe the relationship between the mesoscale heat flux andatmospheric and land-surface characteristics. The analytical model allows usto evaluate the mesoscale flux induced by slope winds from only a few profilemeasurements within a domain. To validate the analytical model the resultingheat flux profiles are compared to profiles of highly resolved wind and temperaturefields obtained by simulations with a mesoscale numerical model.With no or moderate synoptic wind the mesoscale heat flux generated by the slopewind circulation may be as large as, or even larger than, the turbulent fluxes at thesame height. At altitudes lower than the crest of the hills the mesoscale flux is alwayspositive (upward). Generally it causes cooling within the boundary layer and heatingabove. Despite the simplifications made to derive the analytical model, it reproducesthe profiles of the mesoscale flux quite well. According to the analytical model, themesoscale heat flux is governed by the temperature deviation at the slope surface, thedepth of the slope-wind layer, the large-scale lapse rate, and the wavelength of thetopographical features. 相似文献
6.
Influence of Vertical Shear of Basic Tangential Wind on the Development and Maintenance of Typhoon 
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下载免费PDF全文 By using a linear symmetric Conditional Instability of Second Kind (CISK) model containing basic flow, we study the interactions between basic flow and mesoscale disturbances in typhoon. The result shows that in the early stage of typhoon formation, the combined action of vertical shear of basic flow at low level and CISK impels the disturbances to grow rapidly and to move toward the center of typhoon. The development of disturbances, likewise, influences on typhoon’s development and structure. Analysis of the mesoscale disturbances’ development and propagation indicates that the maximum wind region moves toward the center, wind velocity increases, and circulation features of an eye appear. Similarly, when a typhoon decays, the increase of low-level vertical wind shear facilitates the development of mesoscale disturbances. In turn, these mesoscale disturbances will provide typhoon with energy and make the typhoon intensify again. Therefore, it can be said that typhoon has the renewable or self-repair function. 相似文献
7.
Analysis And Simulation Of Surface-Layer Winds Using Multiplicative Cascade Models With Self-Similar Probability Densities 总被引：1，自引：0，他引：1
Statistical analysis techniques based on multiplicative cascades are investigated for use with surface-layer wind data sets collected in the atmospheric boundary layer over flat farm land. The data were found to exhibit multiscaling statistics, allowing the surface-layer winds to be simulated with the use of multiplicative random cascades. The study found evidence that, for the surface-layer at least, these cascade models (andhence the methods of multifractal analysis) should be applied in separate ways to the microscale inertial range, and the mesoscale. This is at odds with the view found in the existing literature, which proposes a `universal multifractal' model to replace the widely held view that there exists separate microscale, mesoscale and synoptic scales for which the processes governing each are different. At least two separate ranges of scaling are suggested for surface-layer wind data, corresponding to the microscale inertial range and the mesoscale. For the case of the mesoscale range, a self-similar distribution of weighting factors was found for the wind speed data themselves, rather than for an intermediate (dissipation) field, as is required for themicroscale data. 相似文献
8.
The South China Sea(SCS) is an eddy-active area. Composite analyses based on 438 mesoscale ocean eddies during 2000–2012 revealed the status of the atmospheric boundary layer is influenced remarkably by such eddies. The results showed cold-core cyclonic(warm-core anticyclonic) eddies tend to cool(warm) the overlying atmosphere and cause surface winds to decelerate(accelerate). More than 5% of the total variance of turbulent heat fluxes, surface wind speed and evaporation rate are induced by mesoscale eddies. Furthermore, mesoscale eddies locally affect the columnar water vapor, cloud liquid water, and rain rate. Dynamical analyses indicated that both variations of atmospheric boundary layer stability and sea level pressure are responsible for atmospheric anomalies over mesoscale eddies. To reveal further details about the mechanisms of atmospheric responses to mesoscale eddies, atmospheric manifestations over a pair of cold and warm eddies in the southwestern SCS were simulated. Eddy-induced heat flux anomalies lead to changes in atmospheric stability. Thus, anomalous turbulence kinetic energy and friction velocity arise over the eddy dipole, which reduce(enhance) the vertical momentum transport over the cold(warm) eddy, resulting in the decrease(increase) of sea surface wind. Diagnoses of the model's momentum balance suggested that wind speed anomalies directly over the eddy dipole are dominated by vertical mixing terms within the atmospheric boundary layer, while wind anomalies on the edges of eddies are produced by atmospheric pressure gradient forces and atmospheric horizontal advection terms. 相似文献
9.
登陆台风Matsa (麦莎) 中尺度扰动特征分析 总被引：6，自引：2，他引：4
地面中尺度自动站和多普勒雷达资料的分析都表明, 台风Matsa登陆后的低层螺旋云带中活跃着中尺度气旋性涡旋系统。本文使用新一代中尺度WRF模式对台风Matsa登陆后的变化特征进行了数值模拟, 使用四维变分多普勒雷达分析系统 (4D-VDRAS) 对台风Matsa多普勒雷达径向风进行了风场反演。在此基础上对台风Matsa登陆后中尺度扰动特性进行了初步探讨; 对台风Matsa与其螺旋云带的中尺度系统之间动能和涡度的相互转换进行了诊断分析。分析表明: (1) 数值模拟和雷达风场反演结果表明, 登陆台风Matsa的低层螺旋云带中活跃着中尺度气旋式涡旋系统, 与之相伴随的为较强的中尺度上升区, 而且, 中尺度垂直上升运动的强弱与雷达对流回波强度成正相关, 中尺度垂直上升运动越强, 雷达对流回波发展越旺盛。 (2) 台风Matsa与其中尺度系统动能转换的诊断分析说明, 低层中尺度系统从台风Matsa环流中获得动能而发展; Matsa在陆地上长久维持主要是从高层获得动能。 (3) 台风Matsa与其中尺度系统涡度转换的诊断分析说明, 低层中尺度系统向Matsa输送正涡度主要依靠中尺度垂直运动来完成; 高层正涡度的转换通过水平输送和垂直输送共同来完成。所以, 中尺度系统所产生的正涡度源源不断地向Matsa输送, 使Matsa的气旋性环流可以在陆地上长久维持。 相似文献
10.
Atmospheric numerical models depend critically on realistic treatment of the lower boundary conditions. In strongly thermally-stratified
conditions, turbulence may be very weak and the models may find it difficult to produce a good forecast near the surface.
Under clear skies and for weak synoptic winds the determining factors are the turbulent kinetic energy and surface-layer parameterizations,
which can be very different between models. Here, two state-of-the-art mesoscale models (MM5 and Meso-NH) are operated under
exactly the same conditions for two different nights over the Duero basin in the Iberian Peninsula: one night with a well-defined
synoptic wind and a second with practically no horizontal pressure gradient. The models are inter-compared and checked against
available information, and their performances are evaluated. 相似文献
11.
Do-Yong Kim Jin-Young Kim Jae-Jin Kim 《Asia-Pacific Journal of Atmospheric Sciences》2013,49(2):183-192
This study investigated multi-decadal variability in the wind resource over the Republic of Korea using the Weather Research and Forecasting (WRF) mesoscale meteorological model. Mesoscale simulations were performed for the period from November 1981 to November 2010. The typical wind climatology over the Korean Peninsula, which is influenced by both continental and oceanic features, was represented by the physics-based mesoscale simulations. Winter had windier conditions with northwesterly flows, whereas less windy with southwesterly flows appeared in summer. The annual mean wind speeds over the Republic of Korea were approximately 2 m s?1 with strong wind in mountainous areas, coastal areas, and islands. The multi-decadal variability in wind speed during the study period was characterized by significant increases (positive trend) over many parts of the study area, even though the various local trends appeared depending on the station locations. The longterm trend in the spatially averaged wind speed was approximately 0.002 m s?1 yr?1. The annual frequency of daily mean wind speeds over 5 m s?1 at the turbine hub height also increased during the study period throughout the Republic of Korea. The present study demonstrates that multi-decadal mesoscale simulations can be useful for climatological assessment of wind energy potential. 相似文献
12.
A numerical mesoscale meteorological model has been applied over the heterogeneous terrain of central Israel in order to study wind energy characteristics of three typical synoptic situations. The supportive nature of this method for observationally oriented wind energy studies has been emphasized. Mesoscale forcing effects on the availability of wind energy and on the exponent, p, in the vertical wind power law are evaluated. 相似文献
13.
摘要：利用西安多普勒天气雷达、L波段风廓线雷达和加密自动站探测资料，结合天气实况，对2018年7月26日发生在陕西一次副热带高压影响下的的强风暴过程进行了中尺度分析。结果表明：（1）本次强风暴伴随的阵风锋共维持了4h，其中有3h出现7级以上的大风，且最大风力10级。（2）在副热带高压影响下，陕西处于高温、高湿气团中，大气层结极不稳定。（3）此次强风暴在高的对流有效位能环境下（CAPE）下，抬升触发的关键因子是关中地区中尺度辐合线，当初生的对流云团下山后，中尺度辐合线触发的对流风暴形成小范围冷池出流与环境风场形成新的辐合线，加强对流风暴发展。（4）当阵风锋移动过程中遇到前方的对流云团时，将低层暖湿空气抬升，并随着上升气流输送到主体对流风暴中，迅速补充了主体风暴的能量，使得主体风暴再次强烈发展，延长了阵风锋的生命史。 相似文献
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15.
Spectral Structure of Small-Scale Turbulent and Mesoscale Fluxes in the Atmospheric Boundary Layer over a Thermally Inhomogeneous Land Surface 总被引：1，自引：0，他引：1
Spectral analysis was performed on aircraft observations of a convective boundary layer (CBL) that developed over a thermally
inhomogeneous, well-marked mesoscale land surface. The observations, part of the GAME-Siberia experiment, were recorded between
April and June 2000 over the Lena River near Yakutsk City. A special integral parameter termed the ‘reduced depth of the CBL’
was used to scale the height of the mixed layer with variable depth. Analysis of wavelet cospectra and spectra facilitated
the separation of fluxes and other variables into small-scale turbulent fluctuations (with scales less than the reduced depth
of the CBL, approximately 2 km) and mesoscale fluctuations (up to 20 km). This separation approach allows for independent
exploration of the scales. Analyses showed that vertical distributions obeyed different laws for small-scale fluxes and mesoscale
fluxes (of sensible heat, water vapour, momentum and carbon dioxide) and for other variables (wind speed and air temperature
fluctuations, coherence and degree of anisotropy). Vertical profiles of small-scale turbulent fluxes showed a strong decay
that differed from generally accepted similarity models for the CBL. Vertical profiles of mesoscale fluxes and other variables
clearly showed sharp inflections at the same relative (with respect to the reduced depth of the CBL) height of approximately
0.55 in the CBL. Conventional similarity models for sensible heat fluxes describe both small-scale turbulent and mesoscale
flows. The present results suggest that mesoscale motions that reach up to the relative level of 0.55 could be initiated by
thermal surface heterogeneity. Entrainment between the upper part of the CBL and the free atmosphere may cause mesoscale motions
in that region of the CBL. 相似文献
16.
Zhang Kesu 《Acta Meteorologica Sinica》1988,2(3):313-322
This is the second part of "Mesoscale Instability of a Baroclinic Basic Flow" which discusses the instability of a basic flow against mesoscale perturbations of transversal type.A bi-mode instability spectrum is obtained by generalizing the Eady model to ageostrophic regime in an f-plane:Eady modes present at the synoptic and subsynoptic scales,while the ageostrophic baroclinic mesoscale modes present at the inertial scales of a few tens to hundreds kilometers.The mesoscale mode is featured by an asymmetric "eat eyes" pattern in the vertical cross section and by an alternative distribution of divergence and vorticity in the horizontal direction.The growth rates of the mesoscale modes are about four times larger than those of Eady modes in magnitudes for the same wind profile.The major energy source for development both Eady mode and mesoscale mode is the baroclinic available energy stored in the rotational basic flow. 相似文献
17.
Abstract The wind climate of the mountainous terrain in the southern Yukon is simulated using the Wind Energy Simulation Toolkit (WEST) developed by the Recherche en Prévision Numérique (RPN) group of Environment Canada and is compared to measurements in the field. WEST combines two models that operate at different spatial scales. The Mesoscale Compressible Community (MC2) model is a mesoscale numerical weather prediction model that produces simulations over large domains of the order of a thousand kilometres. The MC2 model uses long‐term synoptic scale wind climate data from the analysis of radiosonde and other observations to simulate mean wind fields at tens of metres above the ground using a horizontal resolution of a few kilometres. The mesoscale results are used as input to MS‐Micro/3 (Mason and Sykes (1979) version of the Jackson and Hunt (1975) model version for microcomputers/3‐dimensional; MS‐Micro hereafter), a more computer‐efficient, microscale model with simpler linearized momentum equations and a domain restricted to a few tens of kilometres with horizontal grid sizes of tens or hundreds of metres. MS‐Micro provides wind field results at specific wind generator hub heights (typically 30 to 50 m above ground level (AGL)) which are of interest to researchers and developers of wind farms. WEST shows relatively strong correlations between its simulated long‐term mean wind speed and the measurements from ten wind energy monitoring stations. However, in the mountainous terrain of the Yukon, WEST tends to predict wind speeds which are about 40% too high. The model also produces erroneous wind directions and some were perpendicular to valley orientations. The most likely cause of the wind speed and direction errors is the substantially modified 5‐km grid‐spaced mesoscale terrain used in MC2. The WEST simulation was also found to double the wind speeds observed at airport stations and there was poor correlation between the simulated and observed wind speeds. The bias in the model could be attributed to a number of factors, including the use of smoothed topography by the model, the discrepancy between the neutral atmosphere assumed in MS‐Micro and the normally observed stable atmosphere, the application of MS‐Micro to every third grid point of the MC2 output, abnormally high sea level wind speeds in the input climate data for MC2, and a certain degree of disagreement between the land surface characteristics used in the model and those found in the field. At comparatively low computer cost, WEST predicts a wind climate map that compares favourably to the wind measurements made in several locations in the Yukon. However, the problem of the modified terrain in the mountainous regions is the most pressing problem and needs to be addressed before WEST is used in the mountainous regions of Canada. 相似文献
18.
Observations are presented which show a strong correlation between low-level wind behaviour (e.g., rotation near the surface) and the passage of mesoscale pressure systems. The latter are associated with frontal transition zones, are dominated by a pressure-jump line and a mesoscale high pressure area, and produce locally large horizontal pressure gradients. The wind observations are simulated by specifying a time sequence of perturbation pressure gradient and subsequently solving the vertically-integrated momentum equations with appropriate initial conditions. Very good agreement is found between observed and calculated winds; in particular, (i) a 360 ° rotation in wind on passage of the mesoscale high; (ii) wind-shift lines produced dynamically by the pressure-jump line; (iii) rapid linear increase in wind speed on passage of the pressure jump. 相似文献
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大气运动的动能在湍流边界层中的耗散 总被引：1，自引：0，他引：1
在大气能量学中,大气平均运动的动能通过湍流摩擦力转化为脉动运动的能量并最终转化为内能的“变性能量”是大气动能的“汇”,正确估计其大小对研究动能的收支,以至天气系统的生衰,发展均有一定意义。此项由于与湍流通量有关,因而难于从大尺度气象参数计算。以往的研究中,或是将动能平衡方程中其余各项算出,而将此项作为余项估计出,或用地转风由粗浅的边界层模式算出。 相似文献