单体建筑气象抗风参数设计实例分析

利用防城港站1992-2010年的年平均风速及风向、最大风速及风向、极大风速及风向等以及台风、暴雨、大风等灾害性天气资料,分析该地区的风参数气候背景,最大风速及风向和极大风速及风向的分布特征;采用伯努利公式、极值I型概率分布拟合等方法.对50a一遇最大风速、50a一遇极大风速、基本风压和阵风风压等参数进行了计算和分析....     

南阳市主导风向及风速分布

利用南阳市1954～1999年风历史资料,分析了南阳市年、季主导风向及风速的分布情况,并分析了地形对风向风速的影响.     

泰山大风气候特征统计分析

利用泰山气象站1971—2010年近40a逐日风向风速观测资料,统计分析泰山大风天气的气候特征。结果表明:近40a泰山平均风速为7.0m/s,冬季风速最大,春季次之,夏季最小;近40a最大风速为37.7m/s,出现在1977年;年平均大风日数为160.3d,月平均大风日数最多为4月,9月最少,从季节分布看,春季最多,冬季次之,夏季最少,春冬季为大风多发季节。近40a泰山年平均风速、最大风速、年平均大风日数均呈逐年减少趋势。泰山最多风向为西南,除冬季外,春、夏、秋三季均以西南风向最多。泰山大风主要有冷锋后偏北大风、中小尺度系统造成的短时大风、气旋大风等,其中以冷锋后偏北大风和夏半年气旋造成的雷雨大风最为常见。     

南阳市主导风向及风速分布

利用南阳市1954～1999年风历史资料，分析了南阳市年、季主导风向及风速的分布情况，并分析了地形对风向风速的影响。     

陕西省风速风向时空变化特征

利用陕西1971—2000年风速风向观测资料,分析了陕西风速风向空间分布特征及风速的日变化、月际变化、年际变化特征。结果表明,年平均风速较大的区域主要位于陕北长城沿线、渭北和黄河小北干流沿岸以及峡谷地带;各地盛行风向除受天气系统影响外,还受到地形地貌影响,不同区域主导风向差异甚大,变化复杂;陕北、关中年平均风速整体上呈现减小的趋势,各地减小幅度存在差异;平均风速存在明显的季节变化和日变化,2—6月平均风速较大,其余月份月平均风速较小,白天风速较大,夜间风速较小。     

近32a安徽省风速、风向分布特征

基于安徽省1981~2012年近32 a风速、风向资料,利用常规气象统计方法,分析了安徽省平均风速、最大风速以及极大风速的空间分布特征,重点分析了最大风速易出现的方位、季节以及各重现期下的风速分布。结果表明:平均风速与最大风速的空间分布相似,大别山区和皖南山区低海拔地区为风速低值区,黄山以及大别山区以北和以东的平原和丘陵地区为风速大值区。除大别山区北部和皖南山区南部的部分地区外,近32 a全省大部风速普遍呈现显著减少趋势。长江以北地区的最大风速出现偏西风的频率最高,大别山区和皖南山区最大风速出现频率最高的方位空间差异明显。此外,最大风速出现在春季的频率最高。     

近40年南澳县大风特征分析

利用1970—2009年南澳县气象局地面气象观测站风向、风速记录资料进行统计分析。结果表明：近40 a南澳县年平均风速为3.7m/s,秋季最大,冬季次之,夏季最小;年平均最大风速为13.8m/s,春季最大,冬季次之,夏季最小;年平均大风日数为68 d,冬季最多,春季次之,夏季最少;近40 a来的年平均风速、平均最大风速和年大风日数均呈减少趋势;大风日数年内变化呈一峰一谷型;最多风向为ENE风向,NNE和NE风向位居第二,偏西风最少。     

1961～2010年河北省地面风变化特征及成因探讨

利用1961~2010年河北省73个地面气象站风观测资料,结合NCEP/NCAR(2.5°×2.5°)月平均再分析资料和国家气候中心下发的环流指数,采用线性趋势拟合方法,分析地面风速的空间分布以及风速和最大主风向风频的时间变化特征,并对风速减小的成因进行探讨。结果表明:空间上风速呈东北西南向带状分布,依次有大、小、大3个风速带。年平均风速呈减小趋势,减小速率为0.207 m·s-1/10 a;3.0 m/s以下的风速日数呈明显增加趋势,8.0 m/s以上的日数呈显著减小趋势,3.0~8.0 m/s风速的日数没有明显变化趋势。代表站最大主风向为偏南风,最大主风向风频平均每年增加0.54 d。风速的减小与1980年代以后影响我国的环流经向度减小、西风指数增加有关,也与城市化效应的影响有关。     

阿拉山口1957—2007年气候变化特征

根据塔中气象站1996－2008年的气象数据分析、野外观测试验及理论计算,对塔克拉玛干沙漠腹地塔中地区近10a来的风沙环境特征进行了初步分析,结果表明：塔中地区地表沙源平均粒径约为2.88φ（136μm）,属于细砂、极细砂;年平均风速均在2.5m·s-1以下,近10a来呈整体下降趋势,风速的月变化呈单峰分布,最大值出现在6—7月,风向与起沙风向以偏东风为主;2m高度的起沙风速约为4.1 m·s-1;年浮尘、扬沙日数呈波动式上升趋势,年沙尘暴日数呈缓慢下降趋势;年风蚀气候因子平均为28.3。     

泰来城市化对风影响研究

本文使用泰来气象站1971-2004年十六方位风速、风向资料,2009年7月-2010年6月气象站与附近测风塔10 m高度逐时风速、风向资料,分析城市化对风序列的影响。结果表明:泰来县年平均风速呈明显减弱趋势,每10 a大约下降0.36 m/s;泰来测风塔与气象站各方向风速比较,无论是风速差值,还是相对误差均表明城市对风速影响显著,对风向也有较大影响;结合城市空间布局及气象站在城市中的位置,分析泰来十六方位风速变化速率,发现各方向风速下降趋势较为明显,其中受城市影响较大方向风速减弱趋势明显,受城市影响小的方向风速减小趋势较弱。     

Shearing wind helicity and thermal wind helicity

Helicity is defined as H ： V ω, where V and ω are the velocity and vorticity vectors, respectively. Many works have pointed out that the larger the helicity is, the longer the life cycle of the weather system is. However, the direct relationship of the helicity to the evolution of the weather system is not quite clear. In this paper, the concept of helicity is generalized as shearing wind helicity （SWH）. Dynamically, it is found that the average SWH is directly related to the increase of the average cyclonic rotation of the weather system. Physically, it is also pointed out that the SWH, as a matter of fact, is the sum of the torsion terms and the divergence term in the vorticity equation. Thermal wind helicity （TWH）, as a derivative of SWH, is also discussed here because it links the temperature field and the vertical wind field. These two quantities may be effective for diagnosing a weather system. This paper applies these two quantities in cylindrical coordinates to study the development of Hurricane Andrew to validate their practical use. Through analyzing the hurricane, it is found that TWH can well describe the characteristics of the hurricane such as the strong convection and release of latent heat. SWH is not only a good quantity for diagnosing the weather system, but also an effective one for diagnosing the development of the hurricane.     

风廓线雷达在高空风场分析中的应用

利用大连风廓线雷达高时空分辨率风场观测资料,统计2011年雷达站上空各层水平及垂直风速的分布特征.通过分析发现:最大水平风速通常出现在12 km上下,受高空急流的影响,各季节高空最大水平风速出现高度不同,4 km以下高空水平风速随高度的变化各月份存在一定差异,4 km以上至最大风速层,水平风速随高度的升高而增大,最大风速层以上至雷达测量的上限水平风速随高度增加先减小后增大;高空垂直风速在夏季较为明显,秋季次之,冬春季节最小;6月是全年月均垂直风速最大的月份,在500～1300 m高度层存在一个上升气流中心,平均风速大于0.6 m/s,2月各高度平均垂直风速全年最小.     

Variangular wind spirals

The term variangular is introduced to emphasize a significant difference between the present and certain earlier solutions to the problem of organized airmotion within the planetary boundary layer. The latter belong to the family of equiangular wind spirals and have the characteristic that the angle () formed by the vectors of shearing stress and geostrophic departure is invariant with height; it is shown that in this spiral-family, parabolic height-dependency of the effective (eddy) diffusivity (K) alone is permitted, including the asymptotic case of constant K; the famous Ekman spiral as well as the Rossby spiral are two prominent members of the family of equiangular wind spirals. The new variangular theory, as the name implies, permits variation of with height (z) and produces more versatile profiles of wind and stress due to less restraint in K (z). As an example of comparison with observed data, monthly mean wind profiles obtained at Plateau Station, Antarctica, are selected since they exhibit a noteworthy degree of variangularity, in relatively satisfactory agreement with properties of the new theoretical model for wind spirals.National Research Council Visiting Scientist Research Associate, Regional Environments Division, Earth Sciences Laboratory.     

风电场风速数值预报的误差分析及订正

使用WRF模式对内蒙古某风电场区域内的2011年1-6月,50m高度的风速进行了模拟,并结合实测风速对模拟结果进行了评估。在此基础上再利用自回归模型(AR模型)和持续法对WRF模式模拟结果进行了订正预报,订正结果表明:AR模型和持续法都能有效地减小WRF模式风速的模拟误差,AR模型订正效果优于持续法。为能对订正预报时效进行延长,提出了"假设观测值"概念。在AR模型的基础上建立一种新的订正模型称之为New AR模型。其订正预报结果表明:新模型能在12h时效内,改善WRF模式风速模拟精度,其中6h的改进效果较好。     

风廓线雷达中风切变分析方法的初步研究

在风廓线雷达连续输出的风场时间高度显示图上,尝试进行风场的流线分析和风切变值等值线分析,以便用于识别强烈风切变区。在风场变化比较均匀时,分析出的线形分布比较平缓,而在风场变化比较剧烈的区域,风向等值线、垂直风切变等值线和流线三者一致表现出了汇聚特点,线形的分布也异常地密集,分析结果直观地反映出了风场分布的特征和危险性风切变区域,该结果有助于风切变自动识别方法的研究。     

Characteristics of natural wind simulations in the TUM boundary layer wind tunnel

The boundary layer wind tunnel at the Technische Universit?t München was tested for atmospheric boundary layer (ABL) simulations. The ABLs developing above rural, suburban, and urban terrains were reproduced using the Counihan method, i.e., castellated barrier wall, vortex generators, and a fetch of surface roughness elements. A series of flow-characteristic evaluations was performed to investigate the flow development and uniformity. Experimental results presented as mean velocity, turbulence intensity, integral length scale of turbulence, Reynolds stress, and power spectral density of velocity fluctuations were compared with the ESDU data and/or theoretical models. Generated ABL wind-tunnel simulations compare well with the rural, suburban, and urban ABLs. In the test section area used for experiments on structural models, the ABL simulation is developed and uniform. Results of this study indicate the boundary layer wind tunnel at the Technische Universit?t München can be successfully employed in a broad spectrum of engineering, environmental, and micrometeorological studies, where it is required to accurately reproduce ABL characteristics.     

The probability of wind damage in forestry under a changed wind climate

We (1) estimated how the possible changes in wind climate due to climatic change may affect the probability of exceeding critical wind speeds (CWS) expected to cause significant wind damage within a forest management unit located in southern Sweden, (2) analysed how the probability of exceeding an approximate CWS as observed in the management unit would change in different regions in Sweden if expecting a similar kind of forested area to occur in different geographical locations. The topography of the management unit was relatively gentle and the forests were dominated by Norway spruce (Picea abies (L.) Karst.). Seven regions across Sweden were selected for comparison of possible future probability of damaging wind speed. The model-system WINDA was modified and used for calculations of the probability of wind damage together with regionally downscaled climate change scenario (CCS) data. In total, two climate scenarios downscaled using the RCAO model for the control period 1961–1990 and four for the period 2071–2100 were used. The CCSs represent fairly central projections on a 100-year time scale in terms of global mean warming. Although there is ambiguity between different CCSs, the results indicated that the present pattern of more windy conditions in southern than in northern Sweden will remain. For most sites the probability of exceeding the CWS from westerly to south-westerly directions was indicated to remain comparatively high and the probability of damaging wind from south-westerly to south-easterly directions was indicated to increase in many places. For southernmost Sweden increasing probability of exceeding the CWS from the north-westerly to south-easterly wind directions were indicated for all but one CCS. The results were discussed with respect to spatial planning in forestry under a changing wind climate.     

风廓线雷达风场资料质量控制初探

基于2016年2月和8月江西宜春风廓线雷达探测水平风场数据,分别利用扩展经验正交函数(EOF)分析重构法和高斯滤波法对其进行质量控制。结果发现,相比原始观测风场,EOF分析重构法和高斯滤波法均能有效过滤风廓线雷达原始风场的高频脉动。两种方法对比分析发现,对于空间尺度的瞬时扰动,EOF分析重构法质控效果优于高斯滤波法;对于时间尺度的瞬时扰动,高斯滤波法质控效果优于EOF方法。     

基于不同时间尺度风切变指数推算风资源的对比分析

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。