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多普勒声雷达测风与直接测量仪器的观测比较 总被引：3，自引：0，他引：3
文中对多普勒声雷达测风和325 m铁塔上风速、风向仪及超声风速仪的测量值进行了观测比较。结果表明,当信噪比大于1时,两种方法测量的平均风速、风向的相关较好,风速、风向廓线较为接近;声雷达测量的垂直风速平均值和均方根差比超声风速仪的测量值略偏大。这与国外进行的观测比较结果一致。 需要指出,声雷达和直接测量仪器的观测比较中存在一定差异,特别是对比每一次的观测值就可以看出,在某些情况下还存在明显差异。进一步分析声雷达测风产生偏差的原因,对误差做出合理的订正是十分必要的。 相似文献
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电接风向风速仪自记记录的数字化工作是实施珍贵气象资料拯救工程的一项重要内容.由甘肃省气象局和兰州大学联合承担的中国气象局新技术推广项目--"电接风向风速仪自记记录数字化处理系统开发"实现了对电接风向风速仪自记记录的计算机自动数字化处理.选取逐日电接风向风速仪自记记录,通过对人工挑取的定时和日最大风向、风速值与计算机自动数字化处理值进行比较,分析数字化处理系统的精度.分析结果表明,数字化处理系统对风向风速自记记录识别精度基本符合观测规范要求,同时对人工挑取值的时间订正方法做了一定的改进,系统也极大地提高了数字化的效率. 相似文献
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为了获取大气湍流和空间三维风场结构,利用3台同型号的测风激光雷达开展协同观测试验。（1）利用虚拟铁塔协同观测技术开展大气湍流探测,与香河102 m铁塔安装的三维超声风速仪观测结果做对比,32 m处高频（10 Hz）风速的相关系数高达0.92,平均误差为0.77 m/s,均方根误差为0.41 m/s;大气湍流强度（TKE）的相关系数高达0.99,平均误差为?0.02 m2/s2,均方根误差为0.08 m2/s2,并且协同观测的高频风速与三维超声风速仪的观测结果具有相同的频谱结构。（2）利用扫描协同观测技术开展三维风场探测,与铁塔上的常规测风设备相比,其90 m高度处的水平风速和风向的相关系数分别为0.92和0.93,平均误差为?0.41 m/s和0°,均方根误差为0.73 m/s和34°。相比于单台测风激光雷达,基于3台测风激光雷达协同观测技术具有一定的优势:不需要风场水平均匀的假设、探测精度更高等。但其对观测环境的要求较高:观测路径上不能有遮挡、观测必须协同等。在科研业务应用中,需要根据实际的观测需求合理制定观测方案。 相似文献
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本文对稳定大气边界层中风向脉动的特征进行了讨论。用美国波德大气观测台(BAO)气象塔上超声风速仪的观测资料,计算了三种不同稳定大气结构条件下垂直风向σ_w/U和横截风向σ_v/U随时间的变化。结果表明σ_w/U和σ_v/U随平均时间的变化分别与垂直风速和横向风速的能谱分布有关。σ_w/U和σ_w/U随平均时间变化的峰值与能谱峰值的时间尺度相当。 在重力内波的情况下,边界层大气中往往伴随有风向切变。由于稳定大气边界层的结构十分复杂,通常,风向脉动参数和Ri数及高度之间无简单规律。只有在一层逆温时,在风速和Ri数均随高度增加的情况下才有一定的简单关系。 相似文献
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1985年1—3月南极长城站风的特征 总被引：2，自引：0，他引：2
中国南极长城站建在南极乔治岛上,即62°12′59″S,58°57′52″W。该地属亚南极气候,既受南极大陆冷气团的侵袭,也受到极地海洋气团的影响。该站建于1985年2月20日,但从考察队登陆后,1月1日起就开展了气象观测。本文利用建站初期1—3月的资料,分析长城站地面风和高空风的特征。 在登陆初期,地面风资料使用手持轻便风向风速仪,每天于当地时间08,14,20时观测。1月23日后,架起10m高测风铁塔,使用电接风向风速仪,自动记录24h风的变化。经对比观测校验,轻便风向风速仪观测风速系统性偏小。高空风是用小球测风气球观测的,由于当地天气条件恶劣,能见度差,观测次数受到限制。在这次夏季考察中,我们只获得10次高空风探测资料。 相似文献
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该文基于对风杯风速仪动力方程的数值计算和风杯风速仪与超声风速仪平行对比的观测结果,发现专用于近地面层精细风廓线测量的轻型低阈值风杯风速仪测风的过高效应引起的u-error约为1%,因风速平均方法不同（标量平均和矢量平均）引起的DP-error是风杯风速仪测风过高的主要原因,在小风情况下更为明显。DP-error经修正后可获得合理的风速值。 相似文献
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下垫面的非均匀性影响地气通量观测的准确性和代表性,青藏高原复杂下垫面通量印痕分布的研究对地气相互作用的观测、模拟及其天气气候影响均具有重要意义。印痕分析是研究通量观测信息空间代表性的重要方法,通量印痕模型FFP(Flux Footprint Prediction)为计算通量印痕提供了一种行之有效的方法。基于西藏珠穆朗玛大气过程与环境变化国家野外科学观测研究站、阿里荒漠环境综合观测研究站、西藏纳木错高寒湖泊与环境国家野外科学观测研究站、慕士塔格西风带环境综合观测研究站和藏东南高山环境综合观测研究站5个台站2013年观测数据,利用FFP模型对通量印痕进行了模型参数敏感性分析,探讨了不同站点通量印痕分布的时空特点、具体影响因素,进而对观测台站架设提供指导。研究结果表明,通量印痕的主要影响因素为观测高度、风速、风向,下垫面类型为常绿针叶林的林芝站对观测高度、行星边界层高度较其他台站敏感。在青藏高原,使用三维超声风速仪观测数据得到的通量印痕的空间尺度为250～500 m。5个台站中珠峰站白天稳定层结时次最少,占白天数据点的15.69%,阿里站夜间不稳定层结时次最少,占夜间数据点的13.32%。在... 相似文献
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用EN型测风数据处理代替代EL型电接风向风速仪的指示器和记录器,避免了挑取电接风自记纸十分钟风向风速和最大风向风速主观性影响,删除两分钟风向风速观测的人为因素,风向风速实现完全定量观测。但使用中发现如下两种情况须注意: 报警风速是根据阵风风向风速设置,取样采用三秒钟平均风速;航危报报警风速为自动设置,采用当前风向风速即1秒钟风速;风速采样周期不同,报警风速与航危报报警风速有 相似文献
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Errors in turbulence measurements with a sonic anemometer 总被引：1，自引：0，他引：1
Errors in surface-layer wind data obtained by sonic anemometers are estimated as a function of relative wind direction using a comparison between two identical anemometers. The maximum errors in mean windspeed and the standard deviations of the horizontal wind components are found to be between 10 and 20%. Agreement between the size of the measured errors and those calculated from wind-tunnel data is fair.In addition, vertical velocity data are analysed to show the presence of flow distortion induced by the asymmetry in the sonic anemometer probe and the mounting of the probe on the top of a mast. 相似文献
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Tilt corrections over complex terrain and their implication for CO<Subscript>2</Subscript> transport
Jielun Sun 《Boundary-Layer Meteorology》2007,124(2):143-159
Observational data from sonic anemometers are commonly rotated from sonic to streamline coordinates, a procedure that is called
tilt correction. Tilt corrections are often used to post-process air velocity data collected from sonic anemometers to allow
objective interpretation of air flow data relative to the Earth. Since streamline coordinates depend on dynamical characteristics
of the flow, the tilt correction depends not only on temporal and spatial variations of the flow, but also on local circulations.
We found that ensemble- averaged slope flows are approximately parallel to the terrain slope close to the ground within the
canopy layer, but not above, due to the influence of the diurnal variation of local vertical circulations. As a result, the
diurnal variation of the observed vertical velocity in streamline coordinates at 21.5 m above the ground over 11-m tall forest
canopies can be opposite to that calculated from the continuity equation. To estimate CO2 transport over sloping terrain, a workable reference coordinate system is needed such that multiple sonic anemometers have
a common reference relative to the Earth. Streamline coordinate systems can be the choice of the common reference coordinate
system only if flow, at least ensemble-averaged flow, is parallel to terrain slopes. The choice of the reference coordinate
system and its implication in investigation of CO2 transport are discussed.
The National Center for Atmospheric Research is sponsored by the National Science Foundation. 相似文献
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How Well Can We Measure the Vertical Wind Speed? Implications for Fluxes of Energy and Mass 总被引：2，自引：2，他引：0
John Kochendorfer Tilden P. Meyers John Frank William J. Massman Mark W. Heuer 《Boundary-Layer Meteorology》2012,145(2):383-398
Sonic anemometers are capable of measuring the wind speed in all three dimensions at high frequencies (10–50 Hz), and are relied upon to estimate eddy-covariance-based fluxes of mass and energy over a wide variety of surfaces and ecosystems. In this study, wind-velocity measurement errors from a three-dimensional sonic anemometer with a non-orthogonal transducer orientation were estimated for over 100 combinations of angle-of-attack and wind direction using a novel technique to measure the true angle-of-attack and wind speed within the turbulent atmospheric surface layer. Corrections to the vertical wind speed varied from −5 to 37% for all angles-of-attack and wind directions examined. When applied to eddy-covariance data from three NOAA flux sites, the wind-velocity corrections increased the magnitude of CO2 fluxes, sensible heat fluxes, and latent heat fluxes by ≈11%, with the actual magnitude of flux corrections dependent upon sonic anemometer, surface type, and scalar. A sonic anemometer that uses vertically aligned transducers to measure the vertical wind speed was also tested at four angles-of-attack, and corrections to the vertical wind speed measured using this anemometer were within ±1% of zero. Sensible heat fluxes over a forest canopy measured using this anemometer were 15% greater than sensible heat fluxes measured using a sonic anemometer with a non-orthogonal transducer orientation. These results indicate that sensors with a non-orthogonal transducer orientation, which includes the majority of the research-grade three-dimensional sonic anemometers currently in use, should be redesigned to minimize sine errors by measuring the vertical wind speed using one pair of vertically aligned transducers. 相似文献
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Renzo Richiardone Elena Giampiccolo Silvia Ferrarese Massimiliano Manfrin 《Boundary-Layer Meteorology》2008,128(2):277-302
We describe the coordinate transformations that can be used to convert the velocity components measured by a set of sonic
anemometers with time-dependent tilt fluctuations into a single, time-independent coordinate system. By applying the planar
fit method (PFM) to each anemometer dataset, it is possible, for planar flows, to locate the flow plane at each measurement
point and compare its orientation with the topography. Installation on a ship is also considered. An application of this method
to intercomparison data has led to the detection of an instrument error due to a misalignment between the assembly of the
sonic transducers and the anemometer pedestal. If this error occurs, pedestal levelling does not guarantee that measurements
are unbiased. A correction method is proposed and the results of two experiments are shown. Flow planarity at different levels
and flow distortion caused by the mast are highlighted. The influence of the error on the evaluation of the Reynolds stresses
using PFM or the double rotation method and the triple rotation method is discussed and the tilt corrected stresses calculated
using the three methods compared. 相似文献
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S. E. Hobbs 《Boundary-Layer Meteorology》1994,68(3):259-273
The results of calibrations of the airspeed measurement, distance constant and cosine response for a sensitive propellor (vane) anemometer are described. A triad of these anemometers may be used to measure wind velocity, and the estimated uncertainty in this measurement is evaluated for a typical triad and a range of wind directions.The propellor anemometers tested provide sensitivity similar to that of sonic anemometers for research, but at much lower cost (although for a narrower range of wind conditions). Large arrays of the anemometers allow the spatial and temporal structure of wind turbulence to be measured directly. The anemometers have been used for several years, and are robust enough for micrometeorological research. 相似文献
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Two levels of triple-hot-film and sonic anemometers were deployed on a 5.5-m towerduring the Cooperative Atmospheric Surface Exchange Study (CASES-99) in October1999. Each triple-hot-film probe was collocated 50 mm from the sonic sensing path ona common boom. Various problems with using triple-hot-films in the atmosphere toresolve wind components are addressed including the derivation of a yaw angle correction using the collocated sensors. It was found that output voltage drift due to changes in environmental temperature could be monitored and corrected using an automated system. Non-unique solutions to heat transfer equations can be resolved using a collocated sonic anemometer. Multi-resolution decomposition of the hot-film data was used to estimate appropriate day and night averaging periods for turbulent flux measurements in and near the roughness sub-layer. Finally, triple-hot-film measurements of mean wind magnitude (M), turbulent kinetic energy (TKE), sensible heat flux (H), and local friction velocity (u*) are compared to those of the collocated CSAT3 sonic anemometers. Overall, the mean wind magnitudes measured by the triple-hot-film and the collocated sonic sensorswere close, consistent and independent of stability or proximity to the ground. The turbulent statistics, TKE, u*, and H, measured by the two sensor systems were reasonably close together at z = 5 m. However, the ratio of sonic measurement/hot-film measurement decreased toward the ground surface, especially during stable conditions. 相似文献
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A one-dimensional sonic anemometer system suitable for use in measuring near surface heat fluxes is described. It operates by transferring continuous sound waves in alternate directions between a matched pair of cheap ultrasonic transducers. The design and development of the anemometer is described, together with wind tunnel tests, and field experiments, in which the performances of several prototypes are compared with those of other anemometers over stubble and over forest. The results indicate that the device is suitable for measuring eddy correlation heat fluxes to an accuracy better than 5%. 相似文献
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Sonic anemometer path-averaging errors are determined for measurements of inertial-range velocity and temperature power spectra as a function of k
1 p, where k
1 is the streamwise wave number and p is the sonic path length. The attenuation of vertical velocity spectra is found to be quite similar for the CSAT3 and Solent anemometers and to be insensitive to wind direction. The attenuation of the horizontal wind component spectra is noticeably greater for the Solent sonics than for the CSAT3, but those for the CSAT3 have a greater dependence on wind direction. The attenuation of sonic temperature spectra is also found to be quite similar for the CSAT3 and Solent R3 sonics and to be insensitive to wind direction, while that of the Solent R2 is less than that of the other two sonics and has a minor dependence on wind direction. 相似文献
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The frequency response of different types of sonic anemometers due to spatialaveraging of turbulent fluctuations along the sonic path is investigated byapplying modeling procedures and by sonic measurements. The data wereobtained simultaneously at up to 4 heights over extreme smooth andhomogeneous terrain during stationary situations, varying fromslightly stable to unstable. It is shown thatcorrections for the variance of the vertical wind component areneeded for measurements close to the ground. A correction procedure, based ona response function for the vertical wind and on parameters derived frompower spectra, is applied to the measurements. At a height of about onemetre, the variance of the vertical wind component is typicallyunderestimated by about 10%. The error decreases with increasing height. It isalso shown that in the height range down to one metre other turbulencequantities, as for example the variances of the horizontal wind components andthe turbulent fluxes of momentum and sensible heat, are not markedly affectedby the sonic spatial response. Experimental data support these findings. 相似文献
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S. D. Smith 《Boundary-Layer Meteorology》1980,19(3):273-292
The most recent of a series of thrust anemometers, designed for measurement of wind turbulence and eddy fluxes and for long-term unattended operation, is evaluated. Calibration and data analysis procedures are outlined, and results of field trials are given, showing agreement with data from a sonic anemometer. 相似文献