【作者】 耿晓婧；

【导师】 余锡平；

【作者基本信息】 清华大学 ， 水利工程， 2009， 博士

【摘要】 海岸带是人类生产和生活的重要场所,对海岸带微气候动力学特征的研究是深入认识海岸带自然环境的需要,也为海岸带的开发利用和可持续发展提供决策依据。由于下垫面物理特征复杂多样,以及大尺度背景场等因素的影响,海岸带微气候的许多动力学过程及其机理尚未被清晰的认识。本论文建立了海岸带微气候系统的概念,采用数值计算的方法研究了不同条件下海岸带微气候的动力学特征并对各要素之间的相互作用规律进行机理性分析,为进一步深入研究海岸带环境奠定了基础。针对海岸带微气候这一陆海气三者耦合的系统,采用完全可压缩的三维非静力平衡中尺度模式MM5进行数值模拟,并对其预处理模块进行修改使之适应理想条件下小尺度微气候的研究需要。论文以海陆风环流这一典型的海岸带微气候现象为切入点,研究了平直海岸环流的发展过程和结构,得到了合理的结果。沿岸地形形态是海岸带重要的自然属性。论文以矩形海湾和半岛岸线代表不同的海岸线的曲折特性,应用MM5进行理想条件下的计算,得到了两种典型岸线形态下海岸带微气候的变化过程;通过对比分析,得出了岸线凹凸特性及湾岛尺度对微气候的影响规律。沿岸地形被概化为与海岸线平行的倾斜坡面,通过将计算结果与无地形的情况进行比较,明确了斜坡地形影响海岸带微气候要素的动力和热力机制,并且在此基础上进一步研究了斜坡地形的位置和坡度等对海岸带微气候特征的影响。海岸带的开发利用潜力是其重要的社会属性。论文概化了沿岸开发利用对下垫面性质的影响,探讨了不同的开发方式对海岸带微气候的影响。选择建议的江苏沿岸大规模滩涂开发计划,分析了滩涂围垦方案的实施对微气候的影响。结果表明,江苏沿岸滩涂开发将使下垫面净辐射和蒸散发增强,从而减小感热通量,促进近地面气温下降、气压和湿度升高,削弱近岸的海陆风环流。更多还原

【Abstract】 Coastal zone is a special and valuable space for human being. It is special because it is a transient zone between the land and the ocean; it is valuable because it is a unique place for development. Study on the dynamic characteristics of the coastal climate is expected to provide important information on the amenity of the coastal zone. It is thus useful to coastal development. Due to many reasons, the basic features of the coastal climate have not yet been systematically studied. This study is aimed to establish the framework of the coastal climate and investigate the relevant phenomena by numerical method.The fifth-generation NCAR/Penn State non-hydrostatic dynamics mesoscale model MM5 is applied to the numerical study of coastal climate. The pro-process mode in MM5 is modified to facilitate the numerical model for study of idealized problem. The characteristics of the sea breeze under different shore conditions are simulated and discussed based on the numerical results. It is shown that the development and structure of the sea land breeze depends very much on the physical conditions of the coast.Topography is an important natural property of coastal zone. Numerical studies are carried out for two cases with typical change of shoreline profile: one is the case with a bay and the other is the case with a peninsula. The main factors representing the coastal climate, including surface pressure, sea breeze and sensible heat flux, are computed. It is shown that the wind has a tendency to converge or diverge due to the existence of the bay or the peninsula. Large bay or peninsula intensifies the flexural coastline effects. The landform is simplified as an inclined surface parallel to the coastline. Main factors representing the coastal climate are computed on cases in conditions of different slope locations and different grades. Dynamic effects and thermal effects of the slope are also discussed.The effect of different land use on coastal climate is also considered. Afterwards the effects of coastal wasteland use in Jiangsu Province on climate are investigated. It is shown that, as a result of the land use and land cover change, the net radiation and evapotranspiration increased, thereby the air pressure and humidity are increased while the sea land breeze is decreased.更多还原