Assessment of Urban Morphology through Local Climate Zone Clas­sification and Detection of the Changing Building States of Siliguri Municipal Corporation and Its Surrounding Area, West Bengal

Progressive population concentration to the urban centres has fuelled urban expansion in both horizontal as well as vertical direction,consequences in the urban landscape change.This growth resulted in posing many complexities towards sustainable urban development which can be counted by observing the changing proportions of natural landscapes and built up areas.Local climate zones(LCZs),a systematic classification of natural lands and built up lands,are identified in Siliguri Municipal Corporation(SMC)and its surrounding region to explore the spatio temporal complexity of urban growth in recent years.Rapid urbanization and population growth of SMC have led to change the building states from low rise to mid and high rise which added an important feature to the urban landscape dynamics of the area.The work intends to provide the vision of spatial urban morphology of the area through investigation of its changing land use and changing urban built space using the LCZ classification.The study shows that the WUDAPT method can accurately generate LCZs,especially the built type LCZs.The results of the proposed LCZ classification scheme are tested using error matrix for the year 2001 and 2021 having coefficient values of 0.79 and 0.81 respectively.The study explores the changing pattern of building states of SMC using LCZ products,which is essential for proper urban planning implementations.

Relationship between types of urban forest and PM_(2.5) capture at three growth stages of leaves

Particulate matter diameter ≤ 2.5 μm（PM2.5） causes direct harm to human health. Finding forms of urban forest systems that with the ability to reduce the amount of particulate matter in air effectively is the aim of this study. Five commonly cultivated kinds of urban forest types were studied in Beijing city at three stages of leaf growth. Results show that the urban forest system is capable of storing and capturing dust from the air. The types of shrubs and broadleaf trees that have the ability to capture PM2.5from the air are most effective when leaves have fully developed. In the leafless season, the conifer and mixed tree types are the most effective in removing dust from the air. For all kinds of forest types and stages of leaf growth, the PM2.5concentration is highest in the morning but lower in the afternoon and evening. Grassland cannot control particles suspended in the air,but can reduce dust pollution caused by dust from the ground blown by the wind back into the air.

Mapping essential urban land use categories(EULUC)using geospatial big data:Progress,challenges,and opportunities

Urban land use information that reflects socio-economic functions and human activities is critically essential for urban planning,land-scape design,environmental management,health promotion,and biodiversity conservation.Land-use maps outlining the distribution,pattern,and composition of essential urban land use categories(EULUC)have facilitated a wide spectrum of applications and further triggered new opportunities in urban studies.New and improved Earth observations,algorithms,and advanced products for extracting thematic urban information,in association with emer-ging social sensing big data and auxiliary crowdsourcing datasets,all together offer great potentials to mapping fine-resolution EULUC from regional to global scales.Here we review the advances of EULUC mapping research and practices in terms of their data,methods,and applications.Based on the historical retrospect,we summarize the challenges and limitations of current EULUC studies regarding sample collection,mixed land use problem,data and model generalization,and large-scale mapping efforts.Finally,we propose and discuss future opportunities,including cross-scale mapping,optimal integration of multi-source features,global sam-ple libraries from crowdsourcing approaches,advanced machine learning and ensembled classification strategy,open portals for data visualization and sharing,multi-temporal mapping of EULUC change,and implications in urban environmental studies,to facil-itate multi-scale fine-resolution EULUC mapping research.

Atmospheric environmental capacity and urban atmospheric load in China's Mainland

Daily and annual average atmospheric environmental capacity coefficient(A-value) sequences for China's Mainland are calculated from hourly data recorded at 378 ground stations over 1975–2014. A-values at different recurrence intervals are calculated by fitting the sequences to Pearson type III distribution curves. Based on these A-values and source-sink balance(reference concentration 100 μg m^(-3)), atmospheric environmental capacities at the recurrence intervals are calculated for all of China's Mainland and each provincial administrative region. The climate average atmospheric environmental capacity reference value for the entire mainland is 2.169×10~7 t yr^(-1). An urban atmospheric load index is defined for analyses of the impact of population density on the urban atmospheric environment. Analyses suggest that this index is also useful for differentiating whether air quality changes are attributable to varying meteorological conditions or variations of artificial emission rate.Equations guiding the control of unorganized emission sources are derived for preventing air quality deterioration during urban expansion and population concentration.

Exploring complex urban growth and land use efficiency in China's developed regions:implications for territorial spatial planning

Developed regions in China have experienced rapid urban expansion and have consequently induced a series of challenging environmental issues since its economic reform and opening-up.Taking Zhejiang as a case study area,the present paper explores the complex types of urban growth over the last four decades as well as land use efficiency.Moreover,it discusses the implications of the aforementioned on China national territorial spatial planning(TSP).The acquired results have shown that:1)urban expansion has slowed down,exhibiting a three-stage trend of"slight increase(1980-1990)—dramatic growth(1990-2010)—slow growth(after 2010)";2)the complex types of urban growth reveal that the urban diffusion has been gradually controlled and the urban form tends to be more condensed;and 3)the mean values for pure technical efficiency(PTE)and scale efficiency(SE)of urban land use are 0.83 and 0.95 respectively,indicating PTE as the main factor restricting the improvement of urban land use.Based on these results,some beneficial policy implications and suggestions for TSP are provided.First,it is suggested that"Inventory Planning"will be the main direction of TSP other than"Incremental Planning".Secondly,we should pay more attention to the protection of cultivated land and ecological resources.Lastly,TSP should guide the economic growth away from simply relying on resource inputs and steer it toward technology and capital investment.

A comparative study of spatiotemporal patterns of urban expansion in six major cities of the Yangtze River Delta from 1980 to 2015

Introduction:China has been experiencing dramatic urbanization in parallel with its eco-nomic boom over the past three to four decades.The Yangtze River Delta(YRD),as the most important engine in the Chinese economy,has pioneered in the rapid urbanization road of China since the late 19705.We quantifed and compared the spatiotemporal patterns of urban expansion in six major cities in the YRD urban agglomeration between 1980 and 2015.Outcomes:We found that Sha nghai,Nanjing,Hangzhou,Wuxi,Suzhou and Ningbo expanded by an annual rate of 5.4%,5.9%,9.6%,7.4%,6.3%and 8.1%from 1980 to 2015,suggesting larger cities generally possess lower growth rates.Spatiotemporal patterns of urban expansion are defined by multiple forces including physical conditions and urban planning and policy.The urbanization processes in Shanghai,Nanjing and Hangzhou gen-erally conformed with the difusion-coales cence theory as the number of patches(NP)and patch density(PD)of urbanized land peaked and the proportion of leapfrogging urban growth type began to decrease around 2005,which separating their urbanization processes into difusion phase before and coalescence phase after.In contrast,Suzhou,Wuxi and Ningbo is either in the diffusion or in the transition phase from diffusion to coalescence,not showing temporal dynamics of diffusion-coalescence phase across the study period,which might be related to the fact that the urban areas in these three cities were more dispersive in space than that of other cities.Conclusions:These spatially explicit findings are the fundamental cornerstone to understand the characteristics,drivers and consequences of urban expansion in the urban agglomera-tions,and then detect the feasibility of general urbanization theories and further advance in-depth theoretical understanding to support a sustainable urban future.