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1.
Urban heat island (UHI) effect is an important impact factor of the regional climate and ecological environment. How to observe and analyse the spatial distribution of UHI has become an important issue of urban environmental research. In this paper, the near‐surface air temperature of Beijing was derived based on the Landsat/TM satellite imagery on 26 July 2011 to study the near‐surface UHI. A statistical model at 195‐m window size was established to estimate the air temperature, using land surface temperature, normalized difference vegetation index, altitude, and surface albedo as independent variables. The mean absolute error (MAE) of the model was 0.87°C, and the R2 was 0.66, indicating that the method can be used to effectively estimate the air temperature. The air temperature distribution obtained from remote sensing revealed that the UHI effect in Beijing was very significant and showed a concentrated pattern. The heat island intensity was stronger in the southern part than in the northern part of the city. In addition, the relationship between the air temperature and impervious surfaces was analysed. The air temperature increased with increasing impervious surface coverage, and the rate of change depended on the impervious surface coverage. When the impervious surface coverage was below 40 per cent, the temperature increased rapidly with increasing impervious surface coverage, and when the impervious surface coverage was above 40 per cent, the temperature increased slowly. This study provides a new approach to monitor near‐surface UHI and reveals its relationship with impervious surface, providing a scientific reference for urban planning and environmental assessment. 相似文献
2.
This article engages recent debates over gentrification and urban displacement in the global South. While researchers increasingly suggest that gentrification is becoming widespread in “Southern” cities, others argue that such analyses overlook important differences in empirical context and privilege EuroAmerican theoretical frameworks. To respond to this debate, in this article, we outline the concept of higienização (hygienisation), arguing that it captures important contextual factors missed by gentrification. Hygienisation is a Brazilian term that describes a particular form of urban displacement, and is directly informed by legacies of colonialism, racial and class stigma, informality, and state violence. Our objective is to show how “Southern” concepts like hygienisation help urban researchers gain better insight into processes of urban displacement, while also responding to recent calls to decentre and provincialise urban theory. 相似文献
3.
Francis L. Collins 《对极》2016,48(5):1167-1186
This paper explores the politics of migration through a focus on labor migration regimes and the urban lives of migrants in the Seoul Metropolitan Region of South Korea. In particular, it draws attention to the ways in which migrant lives highlight the limits of the contemporary emphasis on control in migration management regimes. The paper contends that while migration management certainly reworks the socio‐legal status of migrants, the desire for control is often displaced in the everyday presence and practices of migrants as urban residents. In order to develop this argument I focus on the notion of the urban periphery as a spatio‐temporal configuration that manifests marginalization but is also potentially generative, innovative and destabilizing. The paper proceeds by exploring three dimensions of the periphery: (1) the mobile commons that emerges in everyday life; (2) the process of becoming undocumented and the subversion of control; and (3) the tactics of recognition that challenge the peripheral location of migrants. In each case the focus on the urban periphery draws attention to the importance of visibility and invisibility in migration, to the uneven spatio‐temporal configuration of migrant lives in the city, and to the ways in which migrant desires constitute a politics that exceeds what is normatively expected of them. 相似文献
4.
PAULINE MCGUIRK ROBYN DOWLING CLARE BRENNAN HARRIET BULKELEY 《Geographical Research》2015,53(1):39-52
5.
Rapid urbanisation and industrialisation have resulted in sharp land cover changes. Urban change not only impacts on land cover but also on urban climate. Land surface and atmospheric modifications due to urbanisation generally lead to a modified thermal climate that is warmer than the surrounding, non-urbanised areas. In this research remote sensing technology was used to evaluate urban growth patterns and its thermal characteristics through mapping impervious surfaces and evaluating thermal infrared images. The case study was carried out in the northern part of Ho Chi Minh City, which has experienced accelerated urban development since the late 1980s. Landsat and Aster images were used to calculate variations in urban impervious surfaces from 1989 to 2006. Thermal bands were processed to obtain radiant surface temperatures for investigating the urban heat island effect associated with increasing impervious surfaces, both spatially and temporally. Impacts of urban development on surface temperature were shown by investigating the surface urban heat island effect intensity. The results show that the built-up area in the northern part of Ho Chi Minh City expanded by 6.5 times between 1989 and 2006. Urban development has altered the magnitude and pattern of the surface urban heat island, with the highest land surface temperature cores found in the industrial (greater than 45oC) and urban areas (within 36oC and 40oC). In suburban and rural areas, where agricultural land still remains with full vegetation cover, the land surface temperature is usually lower. Using remote sensing, the impervious surface was extracted with overall accuracy and a Kappa coefficient for all three years greater than 96%, and the retrieved land surface temperatures with variations from in-situ measurements of less than 2oC. The results presented here indicate that remote sensing can help to spatially monitor urban development and land surface temperature changes over the whole area and over a long period of time. 相似文献