共查询到20条相似文献，搜索用时 62 毫秒
1.
A Comparative Study of Stationary and Non-stationary Wind Models Using Field Measurements 总被引：1，自引：2，他引：1
We present a comparative study of the conventional stationary wind speed model and a newly proposed non-stationary wind speed
model using field measurements. The concept of, and the differences between, the two wind models are briefly reviewed. Wind
data recorded by a field measurement system for wind turbulence parameters (FMS-WTP) of 1-year duration are analyzed using
the two wind models. Comparisons were made between the wind characteristics obtained from the two models, including hourly
mean wind speed, turbulence intensity, the wind spectrum, integral length scale, root coherence function and probability density
function. The effects of wind types (monsoon or typhoon), statistical properties (stationary or non-stationary), and surface
roughness (open-sea fetch or overland fetch) on wind characteristics are discussed. The comparative study demonstrates that
the non-stationary wind model appears to be more appropriate than the conventional stationary wind speed model for characterizing
turbulent winds of one-hour duration over complex terrain. 相似文献
2.
Regional analysis of wind climatic erosivity factor: a case study in fars province, southwest Iran 总被引：1，自引：0，他引：1
Wind erosion climatic erosivity is a measure of the climatic tendency to produce conditions conducive to wind erosion. This research develops a method to determine the regional climate’s tendency to cause wind erosion on the basis of a physically based climatic factor (CE) and linear moment analysis (L-moments) in Fars province, southwest Iran. CE is calculable from wind speed quantiles and other available meteorological data. The wind quantiles can be estimated by a frequency analysis of the available wind data. Wind speed data are often either not available or are of short record length, and thus, CE estimates from such data have large standard errors. In such a situation, data from several sites can be used to estimate wind speed quantiles at each site based on a regional frequency analysis. Monthly averages of maximum daily wind speed of 19 meteorological stations in Fars province were used for regional analysis. Based on L-moment analysis, two homogeneous regions were determined. Regional wind speed quantiles were calculated, and the results were used to calculate CE values for two 6-month wet and dry periods for each homogeneous region. Furthermore, CE values were estimated for each station in the study area using a Weibull distribution, and the results were compared with the regional-based CE values. It showed that CE values estimated using the regional-based approach have smaller sampling variance compared to those obtained from the Weibull method. The proposed method can be used to evaluate the regional risk of wind erosion in arid and semi-arid environments. 相似文献
3.
Laurent Menut Om P. Tripathi Augustin Colette Robert Vautard Emmanouil Flaounas Bertrand Bessagnet 《Climate Dynamics》2013,40(9-10):2515-2533
In order to evaluate the future potential benefits of emission regulation on regional air quality, while taking into account the effects of climate change, off-line air quality projection simulations are driven using weather forcing taken from regional climate models. These regional models are themselves driven by simulations carried out using global climate models (GCM) and economical scenarios. Uncertainties and biases in climate models introduce an additional “climate modeling” source of uncertainty that is to be added to all other types of uncertainties in air quality modeling for policy evaluation. In this article we evaluate the changes in air quality-related weather variables induced by replacing reanalyses-forced by GCM-forced regional climate simulations. As an example we use GCM simulations carried out in the framework of the ERA-interim programme and of the CMIP5 project using the Institut Pierre-Simon Laplace climate model (IPSLcm), driving regional simulations performed in the framework of the EURO-CORDEX programme. In summer, we found compensating deficiencies acting on photochemistry: an overestimation by GCM-driven weather due to a positive bias in short-wave radiation, a negative bias in wind speed, too many stagnant episodes, and a negative temperature bias. In winter, air quality is mostly driven by dispersion, and we could not identify significant differences in either wind or planetary boundary layer height statistics between GCM-driven and reanalyses-driven regional simulations. However, precipitation appears largely overestimated in GCM-driven simulations, which could significantly affect the simulation of aerosol concentrations. The identification of these biases will help interpreting results of future air quality simulations using these data. Despite these, we conclude that the identified differences should not lead to major difficulties in using GCM-driven regional climate simulations for air quality projections. 相似文献
4.
Summary This work presents a statistical study of the wind power potential of three stations in the Catalonia area (Spain) over the 1973–1982 period. These stations correspond to three airports (Barcelona, Palma de Mallorca and Girona), which obviously do not present a high wind power potential and are not the suitable locations for wind power utilization, but which have been chosen for the long record of data stored (10 years). The aim of this work is to provide a model of wind potential in terms of the speed and wind direction, which may be applied to other sites. The wind speed has been modelled by a Weibull distribution function and the wind direction by a normal two-dimensional function. A spectral analysis of both variables has also been carried out. The present study provides an evaluation of the local wind power in the geographic area of Catalonia.With 10 Figures 相似文献
5.
6.
分析了2005年5月11日至6月10日的NCEP-FNL与T213L31分析资料在位势高度、温度和风场上的整体差异,揭示了低层差异最小,差异极值主要分布在3个关键区的特征。进一步通过地形高度差异与位势高度差异的相关性分析,认为青藏高原附近的地形高度差异的极值是引起两种资料位势高度差异的主要原因,并计算分析了这种差异对高原周围中低层大气环流的动力和热力影响。结果显示,在NCEP-FNL中的西南涡强度和热源作用较强,中层风速切变较弱。 相似文献
7.
We describe the results of an experiment focusing on wind speed and momentum fluxes in the atmospheric boundary layer up to
200 m. The measurements were conducted in 1996 at the Cabauw site in the Netherlands. Momentum fluxes are measured using the
K-Gill Propeller Vane. Estimates of the roughness length are derived using various techniques from the wind speed and flux
measurements, and the observed differences are explained by considering the source area of the meteorological parameters.
A clear rough-to-smooth transition is found in the wind speed profiles at Cabauw. The internal boundary layer reaches the
lowest k-vane (20 m) only in the south-west direction where the obstacle-free fetch is about 2 km. The internal boundary layer
is also reflected in the roughness lengths derived from the wind speed profiles. The lower part of the profile (< 40 m) is
not in equilibrium and no reliable roughness analysis can be given. The upper part of the profile can be linked to a large-scale
roughness length. Roughness lengths derived from the horizontal wind speed variance and gustiness have large footprints and
therefore represent a large-scale average roughness. The drag coefficient is more locally determined but still represents
a large-scale roughness length when it is measured above the local internal boundary layer. The roughness length at inhomogeneous
sites can therefore be determined best from drag coefficient measurements just above the local internal boundary layers directly,
or indirectly from horizontal wind speed variance or gustiness. In addition, the momentum and heat fluxes along the tower
are analysed and these show significant variation with height related to stability and possibly surface heterogeneity. It
appears that the dimensionless wind speed gradients scale well with local fluxes for the variety of conditions considered,
including the unstable cases. 相似文献
8.
在核安全分析和环境影响评价中,必须使用到的是小时气象数据。对自动气象站小时风向的计算方法和小时数据如何统计,地面气象规范中和核安全导则中还没有定论,因此本文对小时风向统计方法展开讨论。目前小时风向值的计算方法有算术平均法、滑动平均法、矢量平均法和频率最高法,针对算术平均法和滑动平均法对经过0°的风向统计容易出现误差,本文提出对此的修正方法并对4种计算方法进行了比较。结果表明：文中过零风向修正方法简便准确,小时数据统计方法为正点前10min数据时,修正算术平均法更可靠,但该方法对风速为零时的判断容易出现误差,因此在小风、静风频率高的地方推荐矢量平均法。关于小时数据的划分方法,美国核管会RG1.23与我国核安全导则及地面气象规范中的规定不同,因此文中利用实测资料对不同小时数据统计方法所得结果比较,分析表明,取整点前或其他时段的10min和15min的数据进行平均的风向相关矩阵一致性为97.87%;取4个15min平均值的平均或6个10min数据平均值的平均作为小时值的风向相关矩阵一致性为99.96%,这两种统计方法与取10min和15min的一致性为86.00%,相对较差;取60min时段的平均值作为小时值则与其余方法一致性最差。 相似文献
9.
Daily and sub-daily weather data are often required for hydrological and environmental modeling. Various weather generator programs have been used to generate synthetic climate data where observed climate data are limited. In this study, a weather data generator, ClimGen, was evaluated for generating information on daily precipitation, temperature, and wind speed at four tropical watersheds located in Hawai??i, USA. We also evaluated different daily to sub-daily weather data disaggregation methods for precipitation, air temperature, dew point temperature, and wind speed at M??kaha watershed. The hydrologic significance values of the different disaggregation methods were evaluated using Distributed Hydrology Soil Vegetation Model. MuDRain and diurnal method performed well over uniform distribution in disaggregating daily precipitation. However, the diurnal method is more consistent if accurate estimates of hourly precipitation intensities are desired. All of the air temperature disaggregation methods performed reasonably well, but goodness-of-fit statistics were slightly better for sine curve model with 2?h lag. Cosine model performed better than random model in disaggregating daily wind speed. The largest differences in annual water balance were related to wind speed followed by precipitation and dew point temperature. Simulated hourly streamflow, evapotranspiration, and groundwater recharge were less sensitive to the method of disaggregating daily air temperature. ClimGen performed well in generating the minimum and maximum temperature and wind speed. However, for precipitation, it clearly underestimated the number of extreme rainfall events with an intensity of >100 mm/day in all four locations. ClimGen was unable to replicate the distribution of observed precipitation at three locations (Honolulu, Kahului, and Hilo). ClimGen was able to reproduce the distributions of observed minimum temperature at Kahului and wind speed at Kahului and Hilo. Although the weather data generation and disaggregation methods were concentrated in a few Hawaiian watersheds, the results presented can be used to similar mountainous location settings, as well as any specific locations aimed at furthering the site-specific performance evaluation of these tested models. 相似文献
10.
使用1994年7月至1996年12月大气CH4和地面风现场连续观测资料，分析了瓦里关全球大气本底基准站（36°17′N, 100°54′E，海拔3816 m）地面风变化对大气CH4本底浓度的影响。结果表明，水平风向、风速和垂直风向、风速的变化对大气CH4观测值的影响在春、夏、秋、冬季有明显不同，水平风向NE—ENE—E为CH4测量最主要的局地影响非本底扇区，静风及水平风速大于10 m/s、垂直风速大于±1 m/s对观测结果都有较大影响；由的统计平均还给出了此段期间瓦里关大气CH4在不同季节的浓度分布范围和日变化类型，并分析了可能成因；将地面风数据作为大气CH4本底资料的过滤因子之一，提出了适用于不同使用目的和要求的我国内陆高原大气CH4本底数据筛选方法，本底数据留存率约为原始资料量的50%。 相似文献
11.
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
12.
Marine surface temperature: Observed variations and data requirements 总被引：16，自引：0，他引：16
Measurements of temperature at the ocean surface are an indispensible part of the Global Climate Observing System (GCOS). We describe the varying coverage of these measurements from the mid-nineteenth century through to the present era of satellite data, along with ongoing attempts to augment the available digitized data base. We next survey attempts to remove systematic biases from both sea surface temperature (SST) and marine air temperature (MAT) data and to combinein situ and satellite SSTs in a consistent manner. We also describe new or planned geographically complete climatologies of SST and night MAT for 1961-90. These are expected to be more reliable than existing climatologies in the Southern Ocean and other sparsely-observed areas. The new SST climatology has been used in the construction of an improved geographically-complete data set of sea ice and SST: the techniques used are briefly reviewed, as are other methods of analysis and assessment of worldwide SST.We present global and regional time series of anomalies (i.e. deviations from reference climatology) of SST and night MAT for 1856 to 1994 constructed using the most complete data and best-estimate bias-corrections hitherto available. These series are compared with earlier published series, and are validated by means of comparisons with anomalies of air temperature from coastal and island stations. The sensitivity of the time series to imperfect coverage is assessed by means of frozen grid experiments. The results underscore the need for ongoing development of SST and MAT data bases within GCOS for the detection of climatic change, and for improved methods of analysis to optimally isolate the signals from incomplete data.The British Crown right to retain a non-exclusive royalty-free license in and to any copyright is acknowledged. 相似文献
13.
Despite their potential impact, trends in thunderstorm occurrence in Canada have not received scientific scrutiny, one of the reasons for this likely being lack of data availability. A previous study showed thunderstorm observations at eight staffed weather stations in southern Ontario, Canada, to be accurate for distances within 10?km. We used hourly thunderstorm data from these stations and one additional station to determine whether a trend exists in the thunderstorm record in this region. A Mann-Kendall test and Theil-Sen approach determined that although some stations do have trends in number of thunderstorm hours per year over this time, a consistent increase in the number of thunderstorms that might be expected in a warming climate is not seen. Daily precipitation totals and maximum wind gust speeds were also used as proxies for thunderstorm intensity, neither of which confirmed an increase in the intensity of thunderstorms at these sites over the time period. 相似文献
14.
基于南极18个站点探空气象观测数据对欧洲中期天气预报中心的再分析数据(ERA-Interim)和美国国家环境预报中心的再分析数据(NECP)在南极地区高层大气的适用性进行验证。结果表明:在南极上空,随着高度抬升,探空气象观测数据与两套再分析数据中四个气象要素的差值均逐渐变大,再分析数据数值愈加偏离实际观测数值。两套再分析数据的位势高度和温度与探空观测数据偏差较小;风向则和探空观测数据相差甚远;两套再分析数据的风速与探空观测数据在300 hPa偏差较大。在季节变化中,南极的春季,再分析数据中的位势高度和温度与探空观测数据相差较大,在其他季节相差相对较小。再分析数据中的风速与探空观测数据在南极的夏季相差较小。再分析数据中的风向与探空观测数据存在较大偏差,且差值没有明显的季节变化。尽管两套再分析数据都存在很大偏差,但ERA-Interim数据整体上优于NCEP数据。对比分析也表明,采用这些再分析资料作为初始条件和边界条件驱动南极区域大气模式将带来较大的误差。未来需要加强南极探空观测,改进再分析资料同化和数值模拟系统。 相似文献
15.
An analysis tool for the study of wind speed profiles over the water has been developed. The profiles are analysed using a
modified dimensionless wind speed and dimensionless height, assuming that the sea surface roughness can be predicted by Charnock’s
roughness length model. In this form, the roughness dependency on wind speed is extracted and the variations on the wind profile
are due solely to atmospheric stability. The use of the Charnock’s non-dimensional wind profile is illustrated using data
collected from a meteorological mast installed in the Danish North Sea. The best fit with the observed mean non-dimensional
wind profile under neutral atmospheric conditions is found using a value of 1.2 × 10−2 for Charnock’s parameter. The stability correction on the neutral wind profile suggested by the Businger-Dyer relations was
found to perform well over the sea. 相似文献
16.
Shi Feng Zhang 《Boundary-Layer Meteorology》1981,20(1):117-123
The wind speed distribution with height is analysed by using hourly data for a full year recorded at 6 levels of a 164 m tower at Nanjing. A statistical error analysis shows that power law and logarithmic law are best applicable when the wind is strong. For the height range from 16 to 164 m, the power law represents the actual speed distribution better than does the logarithmic law. 相似文献
17.
Analysis of the surface temperature and wind forecast errors of the NCAR-AirDat operational CONUS 4-km WRF forecasting system 总被引：1，自引：0，他引：1
Andrzej A. Wyszogrodzki Yubao Liu Neil Jacobs Peter Childs Yongxin Zhang Gregory Roux Thomas T. Warner 《Meteorology and Atmospheric Physics》2013,122(3-4):125-143
Investigating the characteristics of model-forecast errors using various statistical and object-oriented methods is necessary for providing useful guidance to end-users and model developers as well. To this end, the random and systematic errors (i.e., biases) of the 2-m temperature and 10-m wind predictions of the NCAR-AirDat weather research and forecasting (WRF)-based real-time four-dimensional data assimilation (RTFDDA) and forecasting system are analyzed. This system has been running operationally over a contiguous United States (CONUS) domain at a 4-km grid spacing with four forecast cycles daily from June 2009 to September 2010. In the result an exceptionally useful forecast dataset was generated and used for studying the error properties of the model forecasts, in terms of both a longer time period and a broader coverage of geographic regions than previously studied. Spatiotemporal characteristics of the errors are investigated based on the 24-h forecasts between June 2009 and April 2010, and the 72-h forecasts between May and September 2010. It was found that the biases of both wind and temperature forecasts vary greatly seasonally and diurnally, with dependency on the forecast length, station elevation, geographical location, and meteorological conditions. The temperature showed systematic cold biases during the daytime at all station elevations and warm biases during the nighttime above 1,000 m above sea level (ASL), while below 600 m ASL cold biases occurred during the nighttime. The forecasts of surface wind speed exhibited strong positive biases during the nighttime, while the negative biases were observed in the spring and summer afternoons. The surface wind speed was mostly over-predicted except for the stations located between 1,000 and 2,100 m ASL, for which negative biases were identified for most forecast cycles. The highest wind-speed errors were found over the high terrain and near sea-level stations. The wind-direction errors were relatively large at the high-terrain elevation in the Rocky and Appalachian mountain ranges and the western coastal areas and the error structure exhibited notable diurnal variability. 相似文献
18.
WRF模式对江苏如东地区风速预报的检验分析 总被引：3，自引：1，他引：2
探讨了WRF模式在风电场的风速或者功率预报中应用的可行性, 主要研究和评估了WRF模式对地处东亚季风区及海陆交界的江苏如东地区夏季和冬季风速的短期预报效能。研究发现WRF模式可以比较好地预报如东站冬季的风速, 24 h预报的风速时间序列和观测资料的相关系数可以达到0.61, 通过置信度99%的检验, 48 h和72 h的预报与观测风速相关系数分别为0.54和0.47, 也能通过置信度99%的检验;相对而言, 模式对夏季风速的预报则要差一些, 24 h的相关系数有0.59, 48 h和72 h的相关系数只有0.47和0.30, 但仍能通过置信度99%的检验。在量值上, 模式预报的风速比观测值都略偏大一些。而江苏南通市预报结果显示, 模式的预报效能要比如东稍高一些, 和如东类似, 模式对该地冬季的预报要好于对夏季风速的预报。从更大尺度范围的分析也表明, 模式对不同地区预报的准确度是不一样的, 对海面以及海陆交界的海岸预报精度要高一些, 在平坦的内陆地区预报也比较好, 但在山区预报效能则较差。总体说来, WRF能胜任风速短期预报, 值得进一步研究和应用。 相似文献
19.
卫星反演海面风场资料能够弥补海上气象测风资料缺乏的不足,对近海风能资源评估具有重要意义。通过ASCAT(Advanced Scatterometer)风速数据与美国及中国近海岸浮标测风资料的对比分析,结果表明,ASCAT风速的均方根误差为1.27 m·s-1。比较利用近海岸浮标逐小时风速及与其相匹配ASCAT瞬时风速计算的各项风能参数,得出ASCAT与浮标的平均风速和风功率密度的残差分别在±0.5 m·s-1和±50 W·m-2以内,该残差占浮标计算结果的比例分别在±8%和±12%以内。使用ASCAT风速资料拟合的Weibull分布函数与浮标的结果较吻合。因此,ASCAT风速资料也能够为海上风能资源评估提供有用的风能参数信息。最后使用ASCAT瞬时风速数据分析了中国近海10 m及70 m高度处的风能资源的空间分布特征,结果表明,台湾海峡平均风速和风功率密度最大。 相似文献
20.
低海拔地区冬季由于凝冻常常会使风向风速传感器冻结,造成风要素资料失真或监测数据缺测,影响数据可用性,造成气象数据历史延续空白,导致无法弥补的历史数据损失。该文利用三穗县国家基准气候站2008—2020年冬季逐日、逐时、逐分钟风向风速、气温、相对湿度以及降水等地面气象监测资料,详细分析冬季冰冻期间风向风速缺测时段的气温、相对湿度、降水等相关信息,找出风向风速冻结与气温、相对湿度、风速大小的对应关系,从而判定风向、风速易冻结的气象要素阈值,采用USB碳纤维发热片,科学搭建低压加热方式,确保风向、风速传感器设备加热时不被灼伤受损,ZQZ-TF风向、风速监测资料连续可靠。 相似文献