1958～2013年武汉市低空风速变化特征分析

采用武汉市1958~2013年逐日探空风资料,利用离差系数、气候倾向率、小波分析、Yamoto突变检验(信噪比指数)等方法,系统揭示该地低空(500、1 000、1 500、2 000 m)年、季、月平均风速的周期性与非周期性变化,通过指数曲线拟合揭示风速随高度变化特征。结果表明:(1)各层月平均风速均为双峰双谷型,7月、3~4月为峰,6月、9~10月为谷,7月达7.0~8.1m/s,谷值仅5.4~5.9m/s,即春夏季风速大,秋季小;(2)风速随高度上升呈线性或指数增加,地面至500m年、季平均风速增加约3.8~4.0m/s(地面仅约2.0m/s),a为0.241~0.294,从500m到2 000m年平均风速从5.9m/s升到6.9m/s,其中冬春季快,秋季慢,风廓线指数a为0.066~0.170;(3)各层年平均风速均呈减小趋势,1 500m、2 000m层达显著,每10a分别减小0.063m/s和0.074m/s,秋季减小显著,夏季减少不明显;(4)月平均风速离差系数为双峰双谷型(500 m为单峰型除外),主峰6~8月离差系数达0.15以上,1月为次峰,这些月风速年际变化大;(5)各层年平均风速周期均有12~30a(2 000m除外)、2~4a,500m层则为7~8a(仅1960’s),前者对应夏秋季,后者对应冬春季;(6)年、季平均风速均在1983~1986年突变上升和1991~1993年突变下降,且突变次数随高度减少,500m层最多,2 000m层除秋季外无突变。深刻认识这些特征可为本地区山区风电场规划、选址、设计、运营提供技术支撑。     

湖北省丘陵山区风能资源特征分析

利用分布在湖北省丘陵山区的12个70 m（80 m）高测风塔一整年的资料，对我省丘陵山区风能资源的若干特征进行了较为详尽的对比分析，找出其中普遍的规律。结果表明：（1）我省山区风速季节变化为春季大，夏季和秋季较小；风速日变化为夜间大白天小，且变化幅度相对较大的测风塔主要分布在低山和中山区域；（2）有效风速频率在79%～92%，破坏性风速出现少；（3）风向频率较为集中，主要分布在偏南和偏北两个相反的方位；（4）风速随高度变化较复杂，10～30 m高度风速增加幅度较大，部分地区30～80 m高度存在等风层或风速随高度减小的情况；（5）有效风速段、大风及主导风向下的湍流强度均为中等。研究成果对湖北省，甚至是南方山区风能资源的合理开发利用将有所裨益     

2015年冬季苏州城市热岛特征研究

基于Landsat土地利用类型分类资料、夜间灯光影像资料、自动气象站资料以及大气边界层探测资料，划分出城市、郊区以及湖区代表站，分析了苏州2015年1月城市热岛日变化、昼夜差异特征以及城、湖温度差日变化特征，并对苏州城市热岛分布特征以及城、湖大气边界层结构差异进行分析。结果显示：(1)白天热岛强度小，09~17时热岛强度均小于1℃，最小值仅为02℃；夜间热岛强度大，19~05时热岛强度维持在12℃以上，最大值为17℃。(2)城、湖温差白天为正，夜间为负，市区变温速率比湖区快约02℃/h。(3) 苏州白天热中心形状不规则，范围大，城郊温差小，夜间形成单一封闭稳定热中心，热中心形状与市区有较好对应，城、郊温差维持在15℃左右。冬季地面盛行西北风，太湖湖陆风现象显著，湖陆风和盛行风向共同影响城市热羽向西南方向发展。（4）城、湖虚位温廓线在白天差异小，均有不稳定边界层形成，夜间市区仍维持不稳定边界层，而湖区有稳定边界层发展，近地层内干岛效应显著。(5)城市热岛影响范围有明显日变化特征，白天城市热岛影响范围小于40 m，夜间大于200 m。     

湖北侧长江三峡河谷地形对风速的影响

选取地处长江三峡河谷(湖北侧)的香溪长江公路大桥桥位区(郭家坝站)附近沿江3个气象站、6个自动站多年的风速、风向资料进行对比分析,讨论了峡谷对河谷内不同区域风速的不同影响。结果表明:在水平方向上,烟墩堡、郭家坝、庙堡等临江3站平均风速偏大、最大风速及极大风速出现大值频次偏高,狭管效应明显,其余非临江站则受局地地形遮蔽影响平均风速偏小、最大风速及极大风速出现大值频率偏低;在垂直方向上,150 m以下风速几乎没有明显的高度变化,实测风廓线指数几乎为0;桥位处阵风性强,阵风系数为1.56。     

四川盆地逆温特征及其对PM2.5的影响研究

基于2000-2020年ERA5逐时温度廓线数据探究了四川盆地逆温特征时空变化,量化了逆温对PM_2.5的贡献,分析了成都和宜宾重污染期间逆温特征及边界层结构。空间上,盆地中部逆温频率最大,在15～25%之间,东部和南部地区次之,盆地西北和西南地区最低;盆地逆温厚度季节变化的空间分布差异较小,整体集中在200～350 m之间;逆温强度冬季最强,中部地区逆温强度最大可达0.45°C/100 m左右。时间上,逆温频率12月至次年4月达到最大,最大可达25%,6～8月最小,逆温厚度3～4月达到最大,多在280.85～400.97 m之间,7～8月最小,逆温强度总体变化不显著,多小于0.4°C/100 m。四川盆地站点逆温频率、厚度、强度与PM_2.5呈正相关,相关系数分别为0.3,0.28和0.25。成都和宜宾逆温特征与PM_2.5的拟合关系表明,成都和宜宾逆温厚度分别为376和374 m时,PM_2.5平均浓度均达到75μg/m³左右,逆温强度与PM_2.5浓度的拟合曲...     

鲁西北海上风资料检验评估分析与实用性建议

目前鲁西北沿海获取的海上风资料可能不准确,东营市气象局经考察研究建设了海面以上10m左右标准站。将东营海区其他几个石油平台站与之进行对比检验评估,发现观测风速失准、风速较实况明显偏小,建设的标准站受石油平台影响东南风风速也偏小,但总体能够代表海面上10m左右风速实况。鉴于目前众多海洋气象观测站高度不具代表性且维护困难、风速失准,建议全省集中建设几个海上风观测标准站并加强维护和质量考核,以其准确的海上风观测资料为全省海洋气象预报服务提供可靠的保障。     

基于泰尔熵指数的中国区域能源效率的差异性分析

本文以能源强度作为能源效率指标,对1995-2010年我国东部、中部和西部地区进行了能源效率分析,并运用泰尔熵指数对三区域能源效率的差异性进行实证研究。研究结果表明,我国总体、区域内、区域间能源效率差异均呈现不断减小的趋势,总体能源效率差异和区域内能源效率差异减小的速度较快,且总体能源效率差异的主要构成部分是区域内能源效率差异。三区域内部能源效率的差异性表现各异,东部和中部地区的内部能源效率差异逐渐减小,而西部地区内部能源效率差异则呈现出波动变化特征。     

长江中下游地区典型旱涝急转气候特征研究

为了研究长江中下游的旱涝急转气候特征，利用标准化降水指数和灾情资料挑选出了1960～2011年长江中下游各水资源二级分区的典型旱涝急转事件，在此基础上分析了其时空分布特征、各区频次和强度的差异，以及旱涝急转期间的大气环流形势。结果表明：长江中下游在这52 a中共有5 a出现了典型的旱涝急转事件，约10 a一遇；其中下游干流的旱涝急转事件强度指数更大、涝期降水量更大。旱涝急转前后的大气环流发生了明显的调整，200 hPa高度场上的南亚地区、东亚高纬地区和850 hPa风场上的东亚副热带地区存在显著的差异     

三峡库区重庆段人类活动强度的景观格局梯度响应

基于三峡库区重庆段1995、2005、2015年土地利用图像，利用ArcGIS和FRAGSTATS软件，并结合夜间灯光数据构建人类活动强度带，分析了三峡库区重庆段在不同人类活动强度带3个时期的景观格局变化特征，并进一步研究了2015年研究区4种面积变化较大的景观类型格局特征随人类活动强度的梯度变化规律。研究结果表明：（1）人类活动的空间分布差异显著，强度由西向东逐渐递减，长江干线流域的人类活动强度相对周边区域更强;（2）在景观水平上，随着人类活动强度的增加，研究区景观斑块数大幅减少，多样性和均匀度指数先增加后减少，连通性有所下降；景观聚集度先减后增，破碎化程度有所增加，但在2015年得到一定改善;（3）在类型水平上，建设用地、水域、草地、低密度植被覆盖林地这4种景观类型能较好地反映景观格局变化特征，其中各景观类型的斑块密度、形状指数和分维数随人类活动强度的变化表现出较为明显的波动；除建设用地外其余景观类型的最大斑块指数和面积变化幅度较小，在人类活动强度最大时的建设用地面积占比和斑块指数分别达到71.2%、35.72%;（4）三峡工程、移民工程、城市化推进以及“退耕还林”等政策实施是三峡库区景观格局演变的重要驱动力。揭示了20a来三峡库区重庆段景观格局沿人类活动强度的梯度变化规律，可为研究区自然资源的合理开发及区域可持续发展提供参考。     

基于MODIS的雅鲁藏布江流域干旱动态监测及对植被胁迫作用的研究

基于MODIS数据利用垂直干旱指数模型和重心模型分析了2011年4月~2012年4月的雅鲁藏布江流域干旱动态变化,并就干旱对植被的胁迫作用做了进一步探讨。研究发现：（1）干旱强度减弱区主要分布于雅鲁藏布江流域的中部,而干旱强度增强区则主要集中于该流域的上游及下游地区;（2）2012年4月份雅鲁藏布江流域的总体干旱强度相比2011年4月有所加重,轻度干旱、重度干旱区均有所增长,而湿润区则有一定减小。干旱强度加重较大的区域主要分布于拉萨河流域及＞3 000～4 000 m、＞4 000～5 000 m高度带;（3）雅鲁藏布江流域的NDVI与PDI的重心迁移具有很好的负相关性,说明其干旱动态变化对植被具有较明显的胁迫作用     

利用CFSR数据开展海上风电场长年代风能资源评估

开展长年代风能资源评估可为海上风电场的可行性研究和风险评估提供依据和支撑。创新性地引入了气候预测系统再分析(CFSR)数据,以江苏响水海上风电场为例开展了长年代风能资源评估,结果表明:CFSR数据10 m高度风速与海上气象塔10 m高度风速的平均偏差为-0.2 m·s~(-1),均方根误差为1.9 m·s~(-1);CFSR数据10 m高度风速与海上气象塔90 m高度风速的相关系数范围在0.359~0.619,相比气象站的相关系数提高了40%~90%;长年代订正得到海上气象塔90 m高度近30 a的风数据,多年平均风速为6.9 m·s~(-1),标准差为0.2 m·s~(-1)(2.9%);测算出海上风电场近30年的等效满负荷小时数,多年平均值为2 423 h,标准差为112 h(4.6%);评估出25 a一遇(海上风电场的寿命期)、10 a一遇、5 a一遇的最小年平均风速分别为6.6、6.7和6.8 m·s~(-1),最小年等效满负荷小时数分别为2 227、2 280和2 329 h。利用CFSR数据开展海上风电场长年代风能资源评估在技术上是可行的。     

Discussion on the Regional Division of the Development Stage of China's Wind Power

This paper constructs the index system of the regional division of the development stage of China's wind power resourc-es, including the index of energy, the index of wind energy endow-ments and other indices. Based on principal component analysis and layered clustering analysis of these indices, and combined with the conceptual function of the development and utilization stage of the wind power, this paper divides the development and utilization stage of the wind power into four stages taking province as the basic yardstick: optimization growth stage, the rapid growth stage,the slow growth stage and the initial growth stage. In addition, this paper briefly discusses the basic strategy that should be adopted in each development stage of wind power resources.     

Exploitation of renewable energy resources for environment‐friendly sustainable development in Saudi Arabia

The recent increase in energy costs, driven by a surge in oil prices, has increased world‐wide efforts on the exploitation of renewable/wind energy resources for environment‐friendly sustainable development and to mitigate future energy challenges. Moreover, experience in the wind energy industry has reached high levels in the field of manufacturing and application. This inevitably increases the merits of wind energy exploitation. In order to exploit wind resources, through the establishment of wind power plants, specific attention must be focused on the characteristics of wind and wind machines. The literature indicates that wind‐energy resources are relatively better along coastlines. In the present study, long‐term hourly mean wind speed data for the period 1986–2003, recorded at Dhahran (Eastern Coastal region, Saudi Arabia), has been analysed to examine the wind characteristics including (but not limited to): yearly/monthly/diurnal variations of wind speed, frequency distribution of wind speed, impact of hub‐height/machine‐size on energy production, etc. Data have been checked/validated for completeness. Data analysis indicated that long‐term monthly average wind speeds ranged from 3.8 to 5.8 m/s.

Concurrently, the study determined monthly average daily energy generation from different sizes of commercial wind machines (150, 250, 600 kW, etc.) to assess the impact of wind machine size on energy yield. The study also estimated annual energy production (MWh/year) from wind farms of different capacities (3, 6, 12, 24 MW, etc.) by utilising different commercial wind energy conversion systems (WECS). It was observed that, for a given 6 MW wind farm size, a cluster of 150 kW wind machines (at 50 m hub‐height) yielded about 32% more energy when compared to a cluster of 600 kW wind machines. The study also estimated the cost of wind‐based electricity (COE, US$/kWh) by using different capacities of commercial WECS. It was found that the COE per kWh is 0.045 US$/kWh for 150 kW wind machine (at 50 m hub‐height) whereas COE was 0.039 US$/kWh for 600 kW wind machine (at 50 m hub‐height). The study also dealt with wind turbine characteristics (such as capacity factor and availability factor). These characteristics are important indicators of wind turbine performance evaluation.     

华山观风电场风能资源评价

利用华山观风电场40 m测风塔2005年4月至2008年3月的测风资料，计算了平均风速、风速频率、风向频率、各方向风能、风功率密度及有效风速时数等各项风能参数，依据国标《风电场风能资源评估方法》（GB/T 18710-2002）中风功率密度等级划分标准对风电场的风能资源进行了评价，并利用距风电场最近的钟祥气象站的累年及同期气象资料，对测风期间的测风背景进行了分析。结果表明：风电场各高度年平均风速在55～57 m/s，年平均风功率密度在190～205 W/m2，年有效风速百分率在808%～823%；华山观主导风向与次多风向完全相反，不同高度两个方向合计频率在449%～505%；各风向风能分布比风向频率更加集中，不同高度主导风向的能量占478%～606%；风功率密度接近3级，具有一定开发利用价值，技术可开发量约3万kW；华山观风电场测风是在年平均风速小于多年平均风速的气候背景下进行的。     

MM5与CALMET对北京地区风能资源的初步模拟

利用MM5与CALMET模拟了北京地区10、30、50和70 m高度的风速和风功率密度分布，结果表明：各高度层风速与风功率密度的地域分布具有一致性，模拟的风速最大区位于门头沟西北部，而昌平西部、房山北部及延庆西部的风速次之，风速最小区位于顺义和东部城区；风功率密度的模拟显示京西地区和西北部地区的风资源较为丰富，北京东部、东南部和东北部及市区周边的风资源相对较小，开发潜力低。利用3座测风塔和3个气象站风速观测数据对模拟结果进行了初步检验，表明MM5与CALMET基本能模拟出风速的月变化和日变化特征，模拟和观测具有较好相关性，但模式存在对黄草梁和北梁地区模拟结果偏高、对涧沟地区模拟结果偏低的系统性误差，这可能与模拟区域地形复杂及模式自身分辨率不够等有关。     

Carbon‐neutral jet‐fuel re‐synthesised from sequestrated CO2

A chemical pathway combining reverse water gas shift, Fischer‐Tropsch synthesis and hydro‐cracking was considered to re‐synthesise jet fuel from CO₂ captured at high purity by oxy‐fuelling of a typical coal‐fired power station (Drax, UK). The oxygen for oxy‐fuelling and hydrogen for the fuel re‐synthesis process are sourced by electrolysis of water. According to material and energy balances , 3.1 MT/year of jet fuel and 1.6 MT/year each of gas oil and naphtha can be produced from the Drax annual emissions of 20 MT of CO₂, sufficient to supply 23% of the UK jet fuel requirements. The overall re‐synthesis requires 16.9 GW, to be sourced renewably from (offshore) wind power, and releases 4.4 GW of exothermic energy giving scope for improvements via process integration. The energy re‐synthesis penalty was 82% ideally and 95% on a practical basis. With the cost of offshore wind power predicted to reduce to 2.0 p/kWh by 2020, this ‘re‐syn’ jet fuel would be competitive with conventional jet fuel, especially if carbon taxes apply. The re‐use of CO₂ sequestrated from coal power stations to form jet‐fuel would halve the combined CO₂ emissions from the coal power and aviation sectors.     

Levellised electricity cost for wind and PV–diesel hybrid system in Oman at selected sites

Solar and wind energy data available for Oman indicate that these two resources are likely to play an important role in the future energy generation in this country. In this paper, a model is designed to assess wind and solar power cost per kWh of energy produced using different sizes of wind machines and photovoltaic (PV) panels at two sites in Oman, which then can be generalised for other locations in Oman. Hourly values of wind speed and solar radiation recorded for several years are used for these locations. The wind profiles from Thumrait and Masirah island are modelled using the Weibull distribution. The cost of wind-based energy is calculated for both locations using different sizes of turbines. Furthermore, this paper presents a study carried out to investigate the economics of using PV only and PV with battery as an energy fuel saver in two villages. The results show that the PV energy utilisation is an attractive option with an energy cost of the selected PV ranges between 0.128 and 0.144 $/kWh at 7.55% discount rate compared to an operating cost of 0.128–0.558 $\kWh for diesel generation, considering the capital cost of diesel units as sunk.     

Stand-alone wind power system with battery/supercapacitor hybrid energy storage

This paper presents a stand-alone wind power system with battery/supercapacitor hybrid energy storage. A stand-alone wind power system mainly consists of a wind turbine, a permanent magnet synchronous generator, hybrid energy storage devices based on a vanadium redox flow battery and a supercapacitor, an AC/DC converter, two bidirectional DC/DC converters, a DC/AC converter and a variable load. Several control strategies for the stand-alone wind power system are involved such as a maximum power point tracking (MPPT) control, a vanadium redox flow battery charge/discharge control and a supercapacitor charge/discharge control. The proposed MPPT control combines a sliding mode control with an extreme search control to capture maximum wind energy. This strategy avoids the necessity of measuring wind velocity, obtaining models or parameters of the wind turbine and calculating the differentials of the power generated from the wind power system and from the speed of the generator. The battery charge/discharge control maintains a constant DC bus voltage. When the battery charging/discharging current reaches the setting threshold, the charge/discharge control of the supercapacitor is triggered to limit the charging/discharging current of the battery. The simulation results show that the proposed method can rapidly respond to variations in wind velocity and load power.     

Deposition velocities for full-scale corn and soybean canopies: A wind tunnel simulation

Deposition velocities have been determined for corn and soybeans in the first 4–6 weeks of growth in a full-scale study of canopy flow in a wind tunnel. Particles of 1, 5, 10 and 15 μm aerodynamic diameter made of sodium florescein were injected into the Environmental Wind Tunnel Facility at Colorado State University. Deposition velocities were determined as a function of free stream velocity (183, 305 and 610 cm/s) and approach flow turbulence intensity (～1% and 8%). Plants were arranged in realistic field configurations. Hot-wire anemometer studies confirmed that the fluid velocity profiles developed in the wind tunnel were similar to the flow realized in canopies in natural fields. An increase in velocity and turbulence intensity was found to decrease the deposition velocities. A minimum deposition velocity was observed at a particle diameter of 5 μm.