Cold air drainage and temperature fields in an urban environment: A case study of topographical influence on climate

1980 ◽  
Vol 14 (3) ◽  
pp. 375-381 ◽  
Author(s):  
Lawrence C. Nkemdirim
2021 ◽  
pp. 105725
Author(s):  
Najmeh Neysani Samany ◽  
Ara Toomanian ◽  
Ali Maher ◽  
Khatereh Hanani ◽  
Ali Reza Zali
Keyword(s):  
At Risk ◽  

2021 ◽  
Author(s):  
◽  
Jack J. Jiang

<p>Cycling is a memory of the past for most of us, the lack of support from the authorities on the cycling infrastructure made it difficult to attract people to cycle in the city. Urban sprawl, traffic congestion, car dependency, environmental pollution and public health concerns have pressured cities around the world to consider reintegrating cycling into the urban environment.  Design as a research method was utilised to investigate the effectiveness of design methodology and workflow for cycling infrastructure from an architecture and design perspective. Using Wellington City as a design case study, this research aimed to improve the legibility, usability and the image of cycling as a mode of transport in the city. To achieve this, a customisable graphical design framework and branding strategies were developed to structure and organise the design components within cycling infrastructure. The findings from the iterative design processes were visualised through the appropriate architectural and presentation conventions.  This research provided an unique architectural perspectives on the issues of cycling infrastructure; the results would support the transportation advisers and urban planners to further the development and integration of cycling, as a viable mode of transport, within the city.</p>


2018 ◽  
Vol 11 (1) ◽  
pp. 142-151
Author(s):  
Giuliana Bonifati

The current historical context is characterised by a significant change in the economic and social fields that have led to the development of the economy of creativity and knowledge. This condition has laid the basis for the rise of a new social class. This radical change in the productive paradigm has started a series of modifications to urban spaces, setting in place a rooted change in the fabric of the city.The objective of this paper is to understand and interpret the nature of the changes under way and to investigate how what occurred in economic and social fields influenced the processes of urban regeneration. Starting from a theoretical background it will examine the concept of creativity applied to economics and social sciences. Secondly, by identifying the urban environment of London as a case study, it will analyze single cases that will show the root of these practices within urban spaces. The purpose of it will be verified by the possibility of building urban transformation strategies that use creativity as the tool of change.


2005 ◽  
Vol 133 (9) ◽  
pp. 2721-2740 ◽  
Author(s):  
Günther Zängl

Abstract This study presents high-resolution numerical simulations in order to examine the dynamical mechanisms controlling the persistence of wintertime cold-air pools in an Alpine valley system. First, a case study of a cold-pool episode is conducted, the formation of which was related to the passage of a warm front north of the Alps. While the preexisting cold air was rapidly advected away in the Alpine foreland, a persistent cold pool was maintained in the inner-Alpine part of the valley system, associated with sustained horizontal temperature differences of up to 10 K over a distance of 30 km. The case study is complemented by a series of semi-idealized simulations, combining realistic topography with idealized large-scale flow conditions. These simulations consider a range of different ambient wind directions in order to investigate their impact on the cold-pool persistence. The results indicate that the most important dynamical mechanism controlling the persistence of cold-air pools in deep Alpine valleys is cold-air drainage toward the Alpine foreland. The preferred direction for such a drainage flow is down the pressure gradient imposed by the (geostrophically balanced) ambient flow. Thus, for a given valley geometry and a given strength of the ambient flow, the probability for persistent cold-air pools mainly depends on the ambient wind direction. If the direction of the imposed pressure gradient matches a sufficiently wide connection to the foreland (a valley or a low pass), then a drainage flow will lead to a rapid removal of the cold air. However, the presence of pronounced lateral constrictions in the connecting valley may strongly reduce the drainage efficiency. Cold-pool erosion by turbulent vertical mixing seems to play a comparatively minor role in deep valley systems as considered in this study.


Author(s):  
Hélène Angot ◽  
Emma Rutkowski ◽  
Maryann Sargent ◽  
Steven C. Wofsy ◽  
Lucy R. Hutyra ◽  
...  

Mercury (Hg) is an environmental toxicant dangerous to human health and the environment. Its anthropogenic emissions are regulated by global, regional, and local policies. Here, we investigate Hg sources in...


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