【作者】 李国栋；

【导师】 王乃昂；

【作者基本信息】 兰州大学 ， 环境科学， 2009， 博士

【摘要】 伴随着城市化进程高速发展的同时，城市化对城市各气候要素产生越来越大的影响，如城市气候出现“五岛”效应特征，这对人类的生产生活产生了一系列影响和危害，同时，城市气候效应对全球变暖的贡献问题已经引起广泛关注。目前，城市气候效应研究在城市生态环境的建设、城市规划、城市建筑设计、城市能源利用以及居民生活健康等应用领域都具有重要的意义。近半个世纪，兰州市城市化进入了一个快速发展的时期，人为和自然因素的综合作用使得兰州城市化气候效应较其它城市表现更加突出和独特，迫切需要对兰州城市气候效应的时空分布特征和形成机制进行研究，本研究主要进行了以下方面的工作：1．在兰州大学本部和榆中校区进行了一年的波文比系统观测实验，利用观测数据并结合兰州市及周边十个气象站自建站以来的气象数据，研究了兰州城市气候各要素的特征和城市近地层空气的温湿特征，分析了“五岛”效应及其日、季节和年际变化特征。研究表明：兰州市较其它城市的城市气候效应更加突出，近五十年兰州市热岛强度及其对兰州市增温的贡献率均高于全国水平，冬季的增温速率和增温幅度是全国水平的2倍。一年四季城市存在明显的城市干岛现象，夏季城市的干岛效应最为显著，冬季较弱；城市湿岛效应并不明显；兰州市城区日照时数和日照百分率呈现下降趋势；兰州风场日落以后河谷山风叠加热力环流，风速较大，白天谷风和热岛环流相互削弱，风速减弱，城区的平均风速小于郊区风速，冬季静风频率高；兰州市并不存在雨岛效应，四季降水量除夏季以外，都是波动递减的，夏季7月份上升幅度不足1mm／10a。近地层大气温湿梯度主要受下垫面影响较大，整体的变化趋势较为一致。2．为了研究兰州市温湿场空间分布格局，首先，在兰州市城区进行了四季各气候要素的汽车流动观测，结合GIS空间插值技术，模拟分析了兰州市城区四季一日内三个时段的热场和湿度场特征。然后，基于TM6热红外遥感数据，利用覃志豪单窗算法和JMS普适性单通道算法，定量反演了兰州城市地表温度场，分析了兰州市地表温度的空间分布规律和剖面特征。研究表明：热场强度高的区域出现在人口和建筑容积率高的商贸区和大型住宅区、能耗大和热源强度高的工业区。低温区主要出现在植被覆盖好、建筑容积率低的城市周边区域。湿度场的分布规律性不强，高湿度区与高植被覆盖区基本一致。绿地、水体，建筑容积率，人口密度，能耗、下垫面性质和城市功能分区的分布差异，使得城市温湿场内部结构存在相当大的差异，其中植被覆盖度的影响最大。在城关区，高温区的分布比较破碎，斑块化程度比较强；在七里河区，以西站、货场、兰石厂和西部物资市场为中心形成了兰州市强度最高的地表高温区。安宁区整体热场强度最弱，强度稍高区域主要分布在黄河市场至十里店一带，大学城区域有逐渐增强的趋势。在西固区，热场强度高的区域基本和生活区的分布范围相一致，在工业厂区热场强度相对并不高。3．为了研究兰州市城市气候效应的形成机制和变化机理，首先，利用波文比观测数据，研究了兰州市区下垫面辐射收支状况和辐射差额的变化特征及其影响因子。然后，通过波文比—能量平衡模型和能量平衡—空气动力学阻抗模型，进行了城市水热通量的估算与城市陆面过程研究，对兰州城市气候形成的根源：能量交换过程进行了分析。采用建筑—城市—土壤同步仿真模型，通过建筑热系统和城市气候的耦合模拟估算了具体条件下的兰州城市热岛效应，得到了作为中尺度城市气候效应研究的城市覆盖层的能量通量的分配特征，以及城市覆盖层内各气候要素的时空分布规律，得到了影响城市热岛效应的城市建筑相关因子的特征，为缓解城市热岛效应提供了理论依据。利用兰州市城市建设和社会经济数据；分析了兰州城市发展相关指标与城市热岛强度之间的关系，发现各项指标与热岛强度均具有较大的相关性，兰州城市气候效应与人口数量、城市规模、城市下垫面状况和城市大气状况等因素关系密切。4．应用基于分形理论的R／S分析方法，对兰州城市气候效应的变化进行了趋势预测，并对各要素时间序列的记忆长度进行了分析。结果表明：各要素时间序列存在着明显的分形结构，年均和四季气温将都呈现上升趋势，变化具有持续性特征；年均和四季相对湿度呈波动下降的趋势仍将持续，而且持续性较强。未来春、冬季节降水量仍将持续递减，夏季降水量仍将持续递增，但其持续性较弱，年平均降水量和秋季降水量变化具有反持续性特征，未来的变化将呈增加的趋势。更多还原

【Abstract】 Urbanization development obviously impact climate factors, and appear urban five islands effectsand a series of impacts for people’s production and living. At present, it has important meaning toresearch the applied field of urban climate at the aspects of environment construction, urban standard,urban architectural design, urban energy sources using and people’s living health. In the recent fiftyyears, urbanization of Lanzhou shows a quick increasing period, integrated effect including artificialand original influence factors bring prominent and particular urban climate effect compared to the othercity. So, it is necessary to research on the temporal-spatial characteristics and formation mechanisms ofurban climate effect in Lanzhou. The following is the research work.1. Observation experiment of Bowen ratio system has been on at Lanzhou University located atcircle road and Yuzhong for about one year, the observation data and meteorological data including tenweather stations are used. Urban climate factor characters, air temperature and humidity character inthe surface boundary layer are researched, and urban five islands effect and their daily, seasonal andannual variation characters are analyzed. The results show that urban climate effect of Lanzhou is moreprominent than the others’ city. In the recent fifty years, urban heat island intensity is 0.21℃/10a, thecontributing rate of urban heat island effect to temperature reaches 56.8% which is higher than thenational average level, the rate and range of increasing temperature are twice as many as the nationalaverage level. Urban dry island is obvious distinct in spring, summer, autumn and winter, and it is themost prominent in summer and is the weakest in winter. Urban moisture island is not distinct. Urbanrain island does not exist.2. Based on GIS spatial interpolation methods and TM6 remote sensing data from Qin ZhihaoMono-window algorithm and Jimenez-Munoz & Sorbrino single-channel algorithm, spatial distributionand profile character of Lanzhou temperature and humidity fields in earth’s surface are obtained. Theresults show that high temperature field appears the commerce section and uptown with high densitypopulation and high building volume and industrial estate with high energy consume and strong heatfountainhead, low temperature field appears the around section with high vegetation cover and lowbuilding volume. Spatial distribution of humidity field is not distinct, high humidity field is related tothe vegetation cover. Difference of greenbelt, water, building volume, population density, energyconsume, underlying surface character and urban function area bring large difference of temperatureand humidity field interior structure.3. Urban heat island is simulated by using the model of build heat system and urban climatecoupling. Distributing character of energy flux and temporal-spatial distribution of different climatefactors at urban cover layer for research of the middle scale of climate effect are obtained. Therelationship between urban heat island and build factor, society economic index are analyzed, theresults show climate effect has close relation to population, urban scale, underlying surface and atmosphere condition.4. The trend of different climate factors based on R/S method is forecasted, and memory length oftime sequence is analyzed. It shows time sequence of different climate factors exist clear fractalstructure, annual average temperature and four seasons temperature show a climbing trend with acharacter of durative. Annual average and four seasons relative humidity show a fluctuant degressivetrend with further strong durative. In the future, precipitation is durative degression in spring and winter,precipitation is still durative weak increase in summer, annual average precipitation and autumn’sprecipitation show inverse durative character with a trend of increase in the future.更多还原