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1.
R. E. Mickle N. J. Cook A. M. Hoff N. O. Jensen J. R. Salmon P. A. Taylor G. Tetzlaff H. W. Teunissen 《Boundary-Layer Meteorology》1988,43(1-2):143-169
This is one of a series of papers on the Askervein Hill Project. It presents results from the Askervein 1982 and 1983 experiments
in the form of vertical profiles of mean wind and turbulence integral statistics at upwind reference locations and at two
hilltop sites. The data were obtained from a variety of sensors including sonic, Gill UVW and cup anemometers mounted on 50,
30, 17 and 10 m towers and TALA kite systems. Comparisons with numerical-model predictions are discussed. 相似文献
2.
One of the objectives of the Askervein Hill Project was to obtain a comprehensive and accurate dataset for verification of models of flow and turbulence over low hills. In the present paper, a retrospective of the 1982 and 1983 Askervein experiments is presented. The field study is described in brief and is related to similar studies conducted in the early 1980s. Data limitations are discussed and applications of numerical and wind-tunnel models to Askervein are outlined. Problems associated with model simulations are noted and model results are compared with the field measurements. 相似文献
3.
利用气象站、探空及NASA再分析资料,对江西省4县山地风场的12座测风塔风速进行订正研究。研究结果表明:测风塔与气象站风速数据相关性较低,相关系数一般远小于0.45;测风塔与探空资料的风速相关系数可达到0.6以上,最高可达到0.8;NASA再分析资料可以作为江西山地风场风速订正参证数据,其与测风塔风速数据相关性较高,相关系数可达到0.54～0.77,大多数测风塔相关系数可达0.7左右。海拔高度小于1000 m的测风塔与NASA 50 m风速的相关系数明显高于其与NASA 850 hPa风速的相关系数,高度为1000—1200 m的测风塔与NASA 50 m风速和与NASA 850 hPa风速的相关系数相差不明显,高度大于1200 m的测风塔与NASA 850 hPa风速的相关系数明显大于其与NASA 50 m风速的相关系数。比值法订正效果略好于线性回归法的,订正后的风功率密度总体偏大。 相似文献
4.
影响测风塔代表性的因素很多,为了合理地确定测风塔观测结果能够代表的区域范围,需要通过适当的方法综合考虑这些因素。湍流通量代表性研究中常用的印痕函数是风速、稳定度、下垫面粗糙度等的函数,可以定量地刻画单点观测结果的代表性。利用印痕函数方法对中国风能资源观测网中来自不同下垫面的44个测风塔2010年的观测结果进行了测风塔资料的代表性分析。首先,根据两层(10、70 m)的风速和温度计算稳定度参数Lp并确定中性层结,粗糙度的计算选取了中性层结条件下满足对数风廓线的资料。然后,利用中性层结下70 m高度主导风向和风向频率较大方位的资料分析了两种印痕函数方法(Schuepp和Hsieh方法)的适用性及代表性范围与粗糙度的关系。两种方法得到的印痕函数对应距离(即代表性范围)比较接近。但是,在复杂山地Schuepp方法已不适用。当粗糙度小于10 m时,粗糙度与印痕函数对应距离的关系可用对数-线性函数描述。根据经验推荐了利用印痕函数积分90%对应的距离以及下垫面显著变化位置来确定测风塔代表范围。但是,印痕函数积分阈值仍需要通过示踪实验或数值模拟检验。 相似文献
5.
J. R. Salmon A. J. Bowen A. M. Hoff R. Johnson R. E. Mickle P. A. Taylor G. Tetzlaff J. L. Walmsley 《Boundary-Layer Meteorology》1988,43(3):247-271
This is one of a series of papers on the Askervein Hill Project. It presents results on the variations in mean wind speed at fixed heights (z) above the ground from linear arrays of anemometer posts and towers. Most of the data are for z = 10 m but some are for z = 3 m. Selected and directionally grouped data from the 55 Mean Flow runs are presented together with mean flow data from Askervein '83 Turbulence runs. Comparisons are made between the data and guideline estimates of fractional speed-up ratio at hilltop locations and between the data and MS3DJH/3 model predictions along the tower lines. There is good agreement in most cases. 相似文献
6.
本文针对择取的103座测风塔资料提出了一套完整的质量控制方案,并基于JRA-55、CRA-40等再分析资料,对测风塔资料的数据质量及质控方案效果进行检验评估。结果表明：(1)有观测数据的测风塔数目在2010—2011年时间段内为最多,有400座左右;随后测风塔数量逐年减少,直到2018年以后,仅存大约50个测风塔有观测数据;(2)对本文选取103座测风塔开展质量控制,发现绝大部分测风塔数据的缺测率、可疑率和错误率都较低,只有少数测风塔在某些观测高度处的上述三个指标较高;(3)无论是温度还是U风,测风塔资料与JRA-55再分析背景场资料的OMB结果都更接近0值,显示出相对于CRA-40再分析资料,JRA-55再分析资料在近地面气象要素重现模拟上具有一定的优势;(4)基于再分析资料对测风塔观测资料质量控制效果进行检验评估结果表明,质量控制后的温度和UV风相对于再分析资料的偏差更接近于0值,标准差减小。相较而言,质量控制后UV风偏差和标准差减小的更多,其应用效果较温度要素好。 相似文献
7.
A three-dimensional nonlinear numerical model, that has been extensively used previously to predict environmental water flows, was applied to predict the flow over an isolated hill, Askervein. Predictions are reported for winds approaching the hill from 210 ° and 180 ° clockwise from north, both under almost neutral atmospheric conditions.The model predictions were compared with data collected during a major field study in 1983. From the comparisons it was concluded that the model predicts the mean flow variables with good accuracy. Larger discrepancies were found for quantities related to the turbulence, pointing to deficiencies in the turbulence model, and perhaps in some of the measurements. 相似文献
8.
The neutrally stratified flow over the Askervein Hill was simulatedusing a terrain-following coordinatesystem and a two-equation(k - ) turbulence model. Calculations were performed on awide range of numerical grids to assess, among other things, theimportance of spatial discretization and the limitations of theturbulence model. Our results showed that a relatively coarse gridwas enough to resolve the flow in the upstream region of the hill;at the hilltop, 10 m above the ground, the speed-up was 10% lessthan the experimental value. The flow's most prominent feature wasa recirculating region in the lee of the hill, which determinedthe main characteristics of the whole downstream flow. This regionhad an intermittent nature and could be fully captured only in the caseof a time-dependent formulation and a third-order discretization ofthe advective terms. The reduction of the characteristic roughnessnear the top of the hill was also taken into account, showing theimportance of this parameter, particularly in the flow close to theground at the summit and in the downstream side of the hill.Calculations involving an enlarged area around the Askervein Hillshowed that the presence of the nearby topography affected the flowneither at the top nor downstream of the Askervein Hill. 相似文献
9.
P. R. Isaac R. Leuning J. M. Hacker H. A. Cleugh P. A. Coppin O. T. Denmead M. R. Raupach 《Boundary-Layer Meteorology》2004,110(1):69-98
Two methods are examined for combining measurements from instrumented aircraftand towers to estimate regional scale evapotranspiration. Aircraft data provided spatially averaged values of properties of the surface, the evaporative fraction and maximum stomatal conductance. These quantities are less sensitive to meteorological conditions than the turbulent fluxes of heat and water vapour themselves. The methods allowed aircraft data collected over several days to be averaged and thus to reduce the random error associated with the temporal under-sampling inherent in aircraft measurements. Evaporative fraction is estimated directly from the aircraft data, while maximum stomatal conductance is estimated by coupling the Penman–Monteith equation to a simple model relating surface conductance to the incoming shortwave radiation and specific humidity saturation deficit. The spatial averages of evaporative fraction and maximum stomatal conductance can then be used with routine tower data to estimate the regional scale evapotranspiration. Data from aircraft flights and six ground based sites during the OASIS field campaign in south–east New South Wales in 1995 have been used to check the methods. Both the evaporative fraction and the maximum stomatal conductance derived from the aircraft data give information on the spatial variability of the surface energy budget at scales from 10 to 100 km. Daily averaged latent heat fluxes estimated using these methods for the OASIS study region agree with the available observations in quasi-stationary conditions or in weakly non-stationary conditions when the data from several aircraft flights are averaged to reduce the impact of short term imbalances in the surface energy budget. 相似文献
10.
The importance of a national or regional network of meteorological stations for improving weather predictions has been recognized for many years. Ground-based automatic weather stations typically observe weather at a height of 2-10 m above ground level(AGL); however, these observations may have two major shortcomings. Large portions of data cannot be used if the station height is significantly lower than the model surface level; and such observations may contain large representativity errors as near-surface observations are often affected by the local environment, such as nearby buildings and tall trees. With the recent introduction of a significant number of mobile communication towers that are typically over40 m AGL in China, a campaign has been proposed to use such towers to build a future observing system with an observing height of 40 m. A series of observing system simulation experiments has been conducted to assess the potential utility of such a future observing system as part of a feasibility study. The experiments were conducted using the Weather Research and Forecasting model and its Rapid Update Cycle data assimilation system. The results revealed the possibility of improving weather forecasting by raising present weather stations to a height of 40 m; this would not only enable more observations to pass the terrain check, but should also reduce interpolation errors. Additionally, improvements for temperature, humidity and wind forecasting could be achieved as the accuracy of the initial conditions increases. 相似文献
11.
René V. Cormier 《Boundary-Layer Meteorology》1975,9(3):315-324
This research provides a study of the behavior of vertically integrated boundary-layer winds (IBLWs). This information should be helpful for both theoretical and practical applications, e.g., boundary-layer parameterization in general circulation models, air pollution models, and low-level parachuting operations. The study concerned itself with winds integrated up to a height of 300 m in the United States. The only data suitable for studying the behavior of IBLWs for such heights were measurements taken on tall towers. An extensive search indicated that data were readily available from only four towers instrumented to or above 300 m. These were located in rural locations in Texas, Oklahoma, Nevada, and South Carolina. At each location, means and coefficients of variation of IBLWs were computed, plotted as a function of time since sunrise/sunset, and compared. The research shows that IBLWs may differ appreciably in magnitude at different locations; may have considerable universality in behavior, and may also be ‘regionally’ dependent; and that IBLWs have a pronounced diurnal variation linked to sunrise/sunset time. 相似文献
12.
More than 8000 10-min profiles of wind and temperature obtained during an extensive field experiment have been analyzed. The study was carried out in the environs of Valladolid (Spain) where a 100-m and a 6-m meteorological tower are located. Less than 20% of data were discarded due to equipment failure. Because of its exceptional flatness, the site is almost ideal for model performance comparisons.Predicted profiles of wind speed and potential temperature at 12, 26, 51, and 100 m heights were obtained using the methods proposed by Berkowicz and Prahm (1982) and San José (1983) based on values observed on a 6 m tower. Statistical t, F, and R tests were used to determine bias, scatter and correlation. The data were classified according to atmospheric stratification and height above ground. Finally, a determination was made of the predicted wind speeds and potential temperatures that fell within the 1 and 20% confidence ranges centered at the measured value. San José's method performed better than did that of Berkowicz and Prahm for the temperature profiles in both unstable and stable conditions. However, no significant differences were found for the wind speed profiles. 相似文献
13.
以内陆某核电厂为例,简述了利用流体力学软件STAR-CCM+模拟内陆核电厂厂区流场及大型自然通风冷却塔雾羽扩散的实现原理,介绍如何将SolidWorks2010建立的核电厂厂区模型导入到STAR-CCM+,给出了STAR-CCM+划分网格的过程,说明了边界层划分的基本假定条件和参数。将STAR-CCM+模拟的数据与风洞实验数据进行了比较,结果显示了较好的一致性。结果表明：在离地面5m的高度处,大型自然通风冷却塔背风面形成较大的空腔区,空腔区风速较小,只有1-1.5 m/s,部分区域达到静风;在冷却塔两侧风速相比入口速度增大了1.66倍;在离开地面100 m的高空,冷却塔背风面的空腔区依然比较明显,冷却塔两侧风速相比入口风速,其变化趋于平稳;在沿主导风向的轴线上,冷却塔两侧风的扰动依次加强;单台冷却塔雾羽最大的抬升高度出现在下风向距离3300 m处,最大抬升高度为690 m,4台冷却塔雾羽在下风向距离3300 m的抬升高度约为850 m,是单台冷却塔的1.23倍。 相似文献
14.
本研究利用四川省会理县测风塔短期2012年2月1日~2013年1月31日期间的70m高度实测逐时数据,经会理和会东气象观测站1981年1月~2010年12月共计30年的风速逐时数据采用长年代法订正推算后,对会理县该研究区域风能资源参数进行计算。结果表明:该区域风能资源应用于并网风力发电分别为“很好”和“好”的等级,具有较好开发潜力;风能和风向较为集中,有利于风机布设;测风塔地处高海拔地形较为平坦的山脊地带,不占用耕地,临近公路,气候较为温和,利于风电场修建。 相似文献
15.
本文介绍了乌鲁木齐市建成区内5座100 m气象塔地理位置,根据逻辑极值检查、僵值检查、时间一致性检查、空间一致性检查和人工干预检查等组成的一套针对气象塔观测资料的质量控制方法和四点滑动平均插值、要素垂直分布拟合和线性回归方法组成的数据插值方法,对乌鲁木齐市从南至北5座100 m气象塔2012年4月1日至2014年4月30日的资料进行质量控制和数据插值。结果表明:该套方案能很好地找出缺测、错误和可疑的数据,结合人工干预,使得检验结果更为可靠。5座气象塔资料的质量是比较好的,正常数据占总数据的97.17%,其中红光山数据质量最好(正常数据占总数据的99.01%)。非正常数据只是少数情况(占总数据的2.83%),包括缺测和错误数据,其中缺测数据占非正常数据的6.23%(出现在米东和燕南立交),错误数据占非正常数据的93.77%。虚假数据占错误数据的89.99%(大部分为风速、风向),僵值数据占错误数据的5.47%(大部分为气温和湿度).超出逻辑极值数据占错误数据的0.41%(只出现在水塔山气温),不符合一致性数据占错误数据的4.13%(主要为湿度,主要在燕南立交)。利用四点中央插值法、每座气象塔要素垂直分布拟合和不同气象塔之间线性回归方法插值气温和相对湿度的效果较好。 相似文献
16.
The need for a thorough knowledge of boundary conditions over the vast oceanic surfaces makes remote sensing appear as the most suitable tool for future development. Remote sensing techniques require calibration data and consequently in-situ experiments to yield those data. Over the sea, aircraft seem to be the most convenient means of conducting validation experiments because they allow exploration of a large range of scales (from local measurements to measurements of pixel scale). This paper reports on some in-situ atmospheric aircraft measurements that were conducted as part of the TOSCANE-T experiment organized by the European Space Agency to calibrate the scatterometer for launch on ERS-1 in the early 1990's for global ocean wind measurement.The data analysed are the thermodynamic and turbulent variables measured by an instrumented aircraft, the Hurel Dubois, flying at a constant level of 50 m over the sea surface. Special attention was drawn to the variability of the boundary conditions within areas of 25 × 30 km. In fact, the two-dimensional fields of fluxes and thermodynamic parameters were inhomogeneous with some rather strong wind distortion.The eddy fluxes were parameterized with the aid of bulk aerodynamic formulations at a basic scale of 30 km samples, which corresponds to the aircraft flux computation legs. The bulk aerodynamic coefficients for momentum and heat were found to remain independent of windspeed (for wind velocities less than 12 m/s). Fluxes and thermodynamic parameters were also investigated at two other scales: the integration scale was either reduced to small areas of which size always remains larger than several characteristic lengths of turbulent transfer, or extended to a large area of 25 × 30km. The results of the bulk aerodynamic relationships appeared to be scale invariant, which would therefore justify the application of average values, within the range of scales under study. 相似文献
17.
气象高塔数据资料弥足珍贵, 对其进行质量控制将为后续科学研究和业务工作的开展提供便利; 此外, 利用塔基观测资料计算空气动力学参数有助于校正模式空气动力学参数理论值。对2017-2018年深圳356 m气象梯度观测塔共13层的每10 s风速、风向、相对湿度、温度探测资料进行数据质量控制, 基于莫宁-奥布霍夫相似理论和数据质量控制后的气象梯度观测塔近地层(10 m、20 m、40 m、50 m和80 m) 1分钟平均的风温资料, 利用最小二乘法拟合迭代计算了近中性条件下深圳气象梯度观测塔下垫面空气动力学粗糙度(z0)和零平面位移(d)。结果表明:深圳气象梯度观测塔的气象探测资料数据质量很高, 连续两年平均数据缺失率为1.28%, 数据错误率为0.01%。近中性边界层条件下, 深圳气象梯度观测塔下垫面空气动力学粗糙度均值为0.35 m, 零平面位移均值为5.33 m, 结果合理可信。研究表明空气动力学参数受下垫面非均匀性、植株柔软性、气流来向、风速等的共同影响。 相似文献
18.
Results on the structure of the convective atmospheric boundary layer based on the analyses of data from the instrumented NSSL-KTVY tower, airborne Doppler lidar, and ground-based Doppler radars are presented. The vertically averaged wind over the boundary layer was found to be insensitive to baroclinicity, supporting the hypothesis of Arya and Wyngaard (1975). The computed momentum flux profiles were affected by baroclinicity. Horizontal wind spectra from lidar, radar, and tower data compared well with each other both in shape and magnitude. A consistent peak found near 4 km in all the computed spectra might have been caused by horizontally symmetric cells with horizontal wavelength 4 times the boundary-layer height as shown in Kuettner (1971) for the case of weak wind shear. 相似文献
19.
利用2014—2018年辽宁省探空资料分析了水平风速的垂直风廓线分布特征。用2座代表性测风塔逐时梯度风观测分析了采用不同高度组合方案计算出风切变指数的月、日变化特征, 分别用月、小时、年风切变指数推算高层风速和风功率密度, 并与实测对比。结果表明: 沈阳相较于大连地区风速随高度增加较快, 180 m高度以上风速基本保持不变, 而大连因其纬度低且靠近海洋, 300 m以下风速均匀上升。在非复杂地形情况下, 距地面10 m高度以上间隔一定高度设立4层风观测, 基本可以满足近地层风资源评估需求。受太阳辐射、下垫面、海陆热力性质差异等影响, 辽宁省风切变指数日变化特征比月变化更显著。利用小时风切变指数推算高层风速和风功率密度的方案优于采用月、年风切变指数方案。风切变指数日变化越显著, 采用逐时风切变指数推算方案越优于其他计算方案。 相似文献
20.
Characteristics of intermittent turbulence events in the stably stratified nocturnal boundary layer are investigated with data collected in the CASES-99 tower array of 300-m radius. The array consists of a central 60-m tower with eddy covariance measurements at eight levels and six satellite towers with eddy covariance measurements at 5 m. A significant increase in the magnitude of vertical wind velocity () and spectral information are used to define the onset of an intermittent turbulence event. Normally, only a subset of 5 m-levels in the tower network experience an intermittent turbulence event concurrent with one at the 5 m-level on the main tower. This behaviour reveals the small horizontal extent of most events. Intermittent turbulence events at the main tower 5-m level are normally confined to a layer much thinner than the 60-m tower height. The turbulent kinetic energy budget is evaluated for intermittent turbulence events observed at the 5-m level on the main tower. Generally, the onset of an intermittent turbulence event is not closely related to the reduction of the gradient Richardson number below 0.25, the critical Richardson number of turbulence generation for linear instability. Possible explanations including the influence of advected turbulence patches are discussed. 相似文献