渤海海峡跨海通道建设对城市经济联系的影响分析

渤海海峡跨海通道建设将极大改变环渤海乃至整个东部沿海的交通格局,势必对其目标城市大连、烟台带来直接的经济影响,同时也会对辽东半岛、山东半岛乃至东北、华北和华东不同尺度地区的经济联系产生深远影响。文章选取山东省17个和辽宁省14个地级市的地区的生产总值、城市人口以及城市间的最短时间距离等指标,测度渤海海峡跨海通道建成前后,对山东、辽宁两省区域城市经济联系的影响。研究表明:渤海海峡跨海通道建成后,对大连、烟台间的经济联系强度有显著提高,各城市经济联系度的平均增幅明显不同;同时,受距离衰减规律的影响,两省的城市分别以大连、烟台为中心,根据距离远近及城市自身发展程度分为4个层次,经济联系强度由内向外逐层次减弱;从整体上看,渤海通道的建设对带动两省城市之间的经济联系度都有大幅度提升。     

不同类型冷却屋顶方案对城市群热环境的缓解效果

利用耦合单层城市冠层模型的中尺度数值模式WRF/UCM,选取8组不同反照率和绿化比例的屋顶冷却方案进行敏感性试验,模拟研究不同冷却屋顶方案对长三角城市群2013年夏季城市热环境的影响,并分析其影响机制.结果表明:不同冷却屋顶方案对城市群热环境的缓解效果与屋顶参数之间呈很强的线性关系.高温热浪天气下,H R 4(反照率为...     

高速铁路和城市蔓延对雾霾污染的异质性影响

为了探寻高铁开通能否抑制雾霾污染以及这种抑制作用在不同城市空间形态下是否存在异质性,本文首先分析了高铁和城市蔓延对雾霾污染的作用机制,在利用LandScan数据测算2003-2016年中国281个地级市城市蔓延指标的基础上,采用动态空间面板模型检验了城市蔓延与雾霾污染的空间动态关系.借助双重差分(DID)模型验证了高铁...     

A comparison of channel erosion in small urban and rural catchments,Armidale, New South Wales

Five years after the cessation of housing construction in a small urban catchment in Armidale, New South Wales, the stability of the channel bed and banks was investigated with the use of erosion pins. After eighteen months of monitoring, the rate of channel bank erosion was found to be 3.6 times greater than that of a nearby rural channel and the rate of knickpoint retreat was 2.4 times greater. There was, however, no evidence to suggest that the urban channel was inherently unstable, but that the increased rate of erosion was the product of changed runoff conditions associated with urban development. Both channels are considered to be in a state of equilibrium.     

Dynamics of fluvial and slope processes in the changing geomorphic environment of singapore

The nature and rates of fluvial and slope processes change over time and space as urbanized areas replace forested land in Singapore. Storm-based and time-based data, from undisturbed rainforests, heavily disturbed construction sites, urban grass-covered slopes and an experimental plot, are collected to observe the impact of rainwater on the soil moisture conditions, surface microtopography, runoff generation, sediment movement, and ground lowering in the three different categories of land use. The undisturbed forested environment is characterized by high throughfall (58% of total rainfall) and frequent negative soil moisture suctions. The slow and unconcentrated overland flow during heavy storms is restricted by the forest floor microtopography. No rills develop. Ground lowering is recorded as 3·2–3·4 mm a^?1. But sediment movement is episodic and suspended sediment concentrations in overland flow are 172–222 mg l^?1. During urban construction, gully development is rapid on the bare slopes, runoff generation, voluminous, and sediment-laden discharges (5200–75498 mg l^?1) lead to sediment plumes at channel mouths. Ground lowering rates are measured at 132·4 mm a^?1. Once grass-covered, runoff carries less suspended sediment (800 mg l^?1) and ground lowering rates are reduced, but depend on the condition of the cover, ranging from 0·2 to 8·2 mm a^?1. As urban development continues, environments are altered both in time as well as spatially.     

城市投资环境的评价模型及应用

本文在对投资单元的量化,评价指标的选择及量化进行探讨的基础上,提出了专家得分和模糊评价二种投资评价模型,并以宁波市为例进行了应用.     

近年来我国城市地理学主要研究领域的新进展

本文对改革开放以来中国城市地理学研究的新进展作了综述，尤其注重新领域的进展和主要观点的概括。本文涉及的主要领域包括：（１）城市化研究；（２）城市发展方针的研究；（３）城市体系研究；（４）城市内部空间结构研究。最后，在研究展望中作者指出，在社会主义市场经济体制下，应开展城市土地和住房以及国际大都市的研究。     

近百余年上海气温变化的若干特征

本文根据1873—1990年上海的年、冬、夏平均气温资料,并利用1956—1990年其郊区气温资料,对城市热岛效应对气温的影响作了处理,重建了近118a的上海气温序列。在此基础上对上海的气温变化特征进行分析,并与同期的北半球气温变化作了比较。结果表明,上海的气温变化有其明显的阶段性、跃变性和周期性。近百余年上海气温变化的总体特征与北半球相似,呈缓慢变暖趋势,但具体的变化过程和幅度有差别,尤其近20多年来的变化与北半球不一致,没有明显的增温现象。     

Flood dynamics of a concrete-lined,urban stream in Kansas City,Missouri

Brush Creek drains a 76·1 km² watershed within urban Kansas City, Missouri and eastern Kansas. A concrete-lined reach trending 6·1 km through the Plaza District of Kansas City, Missouri has been the focus for several major floods over the past ten years. Channel geometry, slope, and floodwater elevations were determined in the field for segments of the concrete-lined section of Brush Creek for a flood event that occurred on September 18, 1986. Discharge was computed by indirect methods and compared to a value determined from a rating curve established by the Water Resources Division of the U.S.G.S. Boundary shear stress, unit stream power, and average velocity were also computed in order to establish a quantitative relationship between sediment distribution, volume, and size fractions; and flow dynamics operating throughout the channel during this event. Boundary shear stress ranged from 91-96 Nm^?2, stream power was 528-557 Wm^?2, while average velocity was 5-8 ms^?1. These values were sufficient to displace concrete slabs as large as 5 m long by 4·6 m wide by 0·23 m thick weighing an estimated 12 245 kg. As the channel was sediment free and unsecured prior to the flood, the distribution of deposits and subsequent channel scour provide valuable evidence for potentially hazardous sections of this urban stream.