Assessing the effects of land use spatial structure on urban heat islands using HJ-1B remote sensing imagery in Wuhan, China

It is well known that there are huge land use and land cover changes (LUCC) all over the world in recent decades, and plenty of ensuing effect appeared on the energy and water balance. This study aims to analyze the impacts of land use and land cover changes on the energy and water balance in the Heihe River Basin of China during 2000–2010, and four key study sites with representative hydrological stations and dramatic LUCC in the past decades were selected to illustrate the responses of the energy and water balance to LUCC. First, LUCC of the Heihe River Basin from 2000 to 2010 was analyzed based on the interpretation of remote sensing images. Then a series of indicators of the energy and water balances were simulated with the Weather Research and Forecasting (WRF) model and corresponding land use and land cover data. Thereafter the impacts of LUCC on the surface energy and water balance were detected and analyzed. The spatial–temporal variance of the impacts of LUCC on energy and water balance in a typical arid inland river basin was specifically presented in following analysis. The results show that different land use/cover conversions result in various energy balances. During this process, the most significant impacts on surface energy balance occurred when grassland was converted to barren or sparsely vegetated land. As for water balance, the impact is measured with variations of precipitation, runoff and evapotranspiration induced by LUCC, which were also remarkable, although seasonal trends of the effects are similar among various land use/cover conversions during 2000–2010. At last, policy suggestions, e.g., shifting the water balance by LUCC to improve the water management, are given to conclude this study.

Impacts of land use and land cover changes on surface energy and water balance in the Heihe River Basin of China, 2000–2010

China has experienced rapid urbanization since 1978, and the dramatic change in land cover is expected to have significant impacts on the climate change. Some models have been used to simulate the relationship between land use and land cover change and climate change; however, there is still no sufficient evidence for the impacts of urbanization on the regional climate. This study aims to identify the impact of urban land use change on regional temperature and precipitation in summer in the Beijing-Tianjin-Tangshan Metropolitan area during 2030–2040 based on the analysis of the simulation results of WRF model. Firstly, we analyzed the land use change and climate change during 1995–2005 in the study area. The impacts of future urbanization on regional climate change were then simulated. The results indicate that urbanization in this area has affected the regional climate and has the potential to increase temperature and precipitation in the summer of 2030–2040. These research results can offer decision-making support information related to future planning strategies in urban environments in consideration of regional climate change.

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Modeling the Impacts of Urbanization on Regional Climate Change: A Case Study in the Beijing-Tianjin-Tangshan Metropolitan Area

Land Use Impacts on Climate

There is a crucial need to achieve a more sustainable management of the world's water resources with serious water scarcity and water pollution. The trans-basin movement of water faces major environmental and engineering challenges and remains controversial. Therefore, improved management of water within basins offers more feasible options to enhance the efficiency of water use. This paper aimed to find out the bottlenecks of integrated catchment management, summarizes the research frontier about integrated catchment management and put forwards some measures, mainly include taking the interaction impacts among water, land and other factors into consideration, evaluating the effectiveness and impacts on different systems of decisions and policies based on appropriate methods, and strengthening watershed management capacity. This paper provides decision-making information for integrated catchment management. The government should strengthen the scientific research in the relationship between water sector and other sectors, and account trans-basin water resources flow. Moreover, participation of different stakeholders is one of key points to promote the success of integrated water resources management (IWRM). Much of the evidence in this paper is from the Heihe River Basin, which is the second largest inland river basin in China. While this evidence comes from a specific area, the integrated economic and environmental modeling presented in this paper can usefully be applied to river basin management elsewhere. Indeed, the international collaboration of researchers evident in this paper is a testament to the worldwide interest in freshwater management issues.

Integrated water resources management for an inland river basin in China

The urban air temperature is gradually rising in all cities in the world. Records of the past years showed that the climate of built-up regions differs significantly from rural regions. One of the most obvious and important modifying effects of urbanization on local climate is the urban heat island (UHI). In order to clarify the spatial distribution of urban thermal field and to evaluate the urban environment quality synthetically, 5 sites including Xidan, the commercial centre of Beijing district; Mudanyuan, the residential areas; Kunming Lake in Summer Palace, the water body; Chaoyang Park, the urban green space; and Wenquan Village, the suburb of Beijing, were investigated from December 2007 to August 2008. The meteorological factors of temperature and humidity of underlying surfaces in these 5 sites were monitored simultaneously in 10 hours period. The results indicate that the temperatures of underlying surfaces in different sampled landscapes were in the order of suburb <water area< green space<residential area<commercial centre in winter, and water area<suburb<green space<residential area<commercial centre in summer; while the humidity was in the opposite order in terms of landscape. The largest temperature difference was 6.3°C at 18:00 h in commercial centre, the largest humidity difference was 25.9% at 8:00 h in residential area compared to rural area. Finally, this paper provides a concise and comprehensive understanding for the temporal and spatial microclimatic dynamics of these four kinds of urban ground cover in the five observation sites. There is influence of urban land use and ground cover on the microclimate of Beijing, monitoring and analyzing urban growth patterns and evaluating their impacts on land surface temperature (LST), provides sound basis for ecological construction, environment improvement, urban planning and management.

Jiaomei Liu

Papers

Influence of different land use on urban microenvironment in Beijing City, China