Assessing multiscale visual appearance characteristics of neighbourhoods using geographically weighted principal component analysis in Shenzhen,China

The neighbourhood is a basic residential unit and is characterized by its physical setting, functional attributes and visual appearance. The visual appearance of a neighbourhood can directly affect the impression of humans regarding the local living environment. Assessing the characteristics of the visual appearance of a neighbourhood is significance for promoting people's physical activities, improving residents' sense of comfort and even ensuring the equality of facilities. However, studies assessing the spatial characteristics of visual appearance are still limited. Therefore, this article applies street view images to quantify the visual appearance of neighbourhoods at multiple scales in Shenzhen, China. Then, geographically weighted principal component analysis (GWPCA) is employed to explore the varying multivariate structures of visual appearance. The results confirm that GWPCA can be effective in assessing the visual appearance characteristics of neighbourhoods while considering spatial heterogeneity. The visual appearance characteristics of neighbourhoods are sensitive to both the spatial location and analysis scale. The extracted geographically weighted principal components (GWPCs) can represent the original screen elements by emphasizing certain comprehensive concepts, such as walkability, accessibility and vibrancy. The exploratory findings of this article allow for an improvement of studies on spatial quality at the human scale and could potentially guide neighbourhood planning and street design.     

Consolidated bioprocessing of hydrogen production from agave biomass by Clostridium acetobutylicum and bovine ruminal fluid

The biological production of H₂ represents a renewable and eco-friendly energy alternative compared to fossil fuels. However, its production from lignocellulose involves the use of expensive enzymatic complexes. In the present work, the production of H₂ from pretreated agave biomass was evaluated by means of a Consolidated Bioprocess (CBP). This strategy was carried through the interaction of cellulose-degrading microorganisms obtained from bovine ruminal fluid (BRF) capable of enhancing H₂ production by Clostridium acetobutylicum. The results obtained show the capacity of BRF to hydrolyze the acid pretreated agave, improving the production of H₂ in the experiments where the inoculum of Clostridium was greater. According to the results, production of H₂ is significantly affected by the increase of the solids loading, obtaining a maximum H₂ production at a 10% of solids loading, pH 5.5 and 35 °C, representing a yield of 150 L of H₂ per Kg of biomass in 264 h.     

Directional multi-scale analysis and simulation of urban expansion in Auckland,New Zealand using logistic cellular automata

In characterising urban expansion, existing landscape indices lack consideration for directional changes. This limitation is overcome with the proposed directional perspective (urban expansion vector) in this study, which can identify both the urban expansion mode and local changes at the patch and sectorial levels, and reveal the varying importance of the same urbanisation factors at multi-scales. Landscape (expansion) indices (LEI) and directional characteristics of newly grown urban patches were derived / extracted from time-series (1975–2016) satellite images in the Auckland metropolitan area, based on which urban expansion was simulated using logistic regression cellular automata at both the global and sectorial levels. The results show that Auckland urban development was mostly compact with “organic” being the dominant mode of expansion throughout the last 40 years. Most urban development took place in the southeast (270° - 360°) and northwest (90° - 180°) sectors, within which urban expansion occurred mostly in places that had favourable transportation infrastructures and are close to the CBD. The influence of the nine factors of urbanisation studied varies with scale and sector. In general, accessibility (e.g., proximity to roads and the CBD) and amenity (e.g., distance to transportation and schools) are more important than physical variables (e.g., terrain) in affecting urban development. The localised sectorial simulation result is in a closer agreement with the observed urbanisation than the global, sectorless result. The directional perspective, in conjunction with the LEI and other landscape indices, can effectively characterise the spatiotemporal patterns of urban expansion. More importantly, it improves the simulation accuracy of urban expansion (e.g., simulation kappa rising from 0.024 to 0.161 in the northwest sector, and from 0.31 to 0.40 in the southeast sector) for a monocentric city whose urbanisation is strongly sectorial.     

BiFlowLISA: Measuring spatial association for bivariate flow data

Spatial flow data are often used to represent spatial interaction phenomena such as daily commuting trips, human or animal migrations, and the exchanges of commodities, capital, or even information between regions. With the increasingly available large volume of flow data in fine spatiotemporal resolution, exploratory spatial data analysis (ESDA) has become more important than ever to gain understanding of the data and the story behind it. A major group of flow-related ESDA methods focus on measuring spatial associations, which proves useful in improving the prediction power and interpretability of spatial interaction model (SIM), as well as in identifying local clusters and outliers of flow events. This paper introduces a new spatial statistical method called BiFlowLISA—a local indicator of spatial association of bivariate flow data. BiFlowLISA evaluates the association between two types of flows in close proximity, in other words, how the value of type-I flows associate with the value of nearby type-II flows. We develop BiFlowLISA by extending the local bivariate Moran's I to the flow context. We also put forth its global version to measure the global patterns, and another variant of BiFlowLISA to measure both spatial and in-situ correlations at the same time. Several flow-specific issues are discussed and solved, including flow neighbor definition, OD matrix sparsity, and conditional permutation. We experiment with synthetic datasets to verify its functionality and to summarize its characteristics. A case study of taxi and ride-hailing services in New York City demonstrates its usefulness in the comparative analysis of the spatial patterns of two types of travel flows. More applications of BiFlowLISA await to be explored in the future.     

The costs of mitigating carbon emissions in China: findings from China MARKAL-MACRO modeling

In this paper MARKAL-MACRO, an integrated energy-environment-economy model, is used to generate China’s reference scenario for future energy development and carbon emission through the year 2050. The results show that with great efforts on structure adjustment, energy efficiency improvement and energy substitution, China’s primary energy consumption is expected to be 4818 Mtce and carbon emission 2394 MtC by 2050 with annual decrease rate of 3% for the carbon intensity per GDP during the period 2000–2050. On the basis of this reference scenario, China’s marginal abatement cost curves of carbon for the year 2010, 2020 and 2030 are derived from the model, and the impacts of carbon emission abatement on GDP are also simulated. The results are compared with those from other sources. The research shows that the marginal abatement costs vary from 12US$/tC to 216US$/tC and the rates of GDP losses relative to reference range from 0.1% to 2.54% for the reduction rates between 5% and 45%. Both the marginal abatement costs and the rates of GDP losses further enlarge on condition that the maximum capacity of nuclear power is constrained to 240 GW or 160 GW by 2050. The paper concludes that China's costs of carbon abatement is rather high in case of carbon emissions are further cut beyond the reference scenario, and China's carbon abatement room is limited due to her coal-dominant energy resource characteristic. As economic development still remains the priority and per capita income as well as per capita carbon emission are far below the world average, it will be more realistic for China to make continuous contributions to combating global climate change by implementing sustainable development strategy domestically and playing an active role in the international carbon mitigation cooperation mechanisms rather than accepting a carbon emission ceiling.     

社会经济统计地理信息系统中统计图表功能的实现

社会经济统计地理信息系统中统计图表功能需具有图形丰富、可免费分发的特点.为了实现多地区、多时间、多指标的多维统计数据的显示与保存功能,提高用户对数据的分析能力,基于ChartDirector构造出SuperChart控件,并提供了标准接口.     

Changes of runoff components in the source region of the Yellow River during the second half of the twentieth century

In the 1990s, the runoff volume at Tangnaihai hydrologic station decreased remarkably. The runoff components were separated and climate influences on it were analysed. Researches show that in summers, the decrease in stream flow was mainly caused by the decrease in direct flow, while during fall seasons it resulted from decrease in both base flow and direct flow. For the whole Yellow River study source region, change in precipitation both spatially and temporally was the main contributor to the decrease in runoff and its components.     

Research on Lake Variation in Tibetan Plateau based on Space-borne Laser Radar

Based on ICESat data and temperature and precipitation from 2003 to 2010 and used ANUSPLINE interpolation method and Theil\|Sen’s method,we analyzed and discussed lake water level change characteristic from 2003 to 2010,as well as the temporal\|spatial response of lake water level to climate changes.the results showed that most of lakes mainly distribute in the central and western region of TP,and their lake water levels are mainly between 4 500 to 5 000 meters.Lake water level of Tak kyel and Yamzhog Yumco in the southern of TP as well as Panggong in the western of TP showed a decreasing trend.Analysis of the relationship between lake water level and climate factor indicated that lake water level in different basin showed different trends because of varied temperature and precipitation.the increasing trend of lake volume was not only dependent on direct supply of precipitation,but also effected by melted water from glaciers and snow due to climate warming.     

A practical approach to retrieving the finer areas of algal bloom in inland lakes from coarse spatial resolution satellite data

Moderate Resolution Imaging Spectroradiometer (MODIS) and Visible Infrared Imaging Radiometer Suite (VIIRS) images have been used to monitor algal blooms in the open ocean, coastal waters, and inland lakes. However, it is difficult to obtain an accurate definition of algal bloom areas in inland lakes due to the spatial resolution of the generated images. This study developed a practical approach that uses a linear spectral mixing model with a moving window (LSMM), to obtain a finer algal bloom area. The approach analyses the differences in areas of algal bloom retrieved from MODIS images with 250 and 500 m spatial resolutions from 2012 to 2015 and synchronous VIIRS images with 750 m spatial resolution. Forty-two data sets with 126 satellite images were selected. The results showed that the average relative area difference (RAD) of algal bloom in the MODIS 500 m image was approximately 21.31% compared with the MODIS 250 m image and approximately 33.77% compared with the VIIRS image. A 5 × 5 window size was selected for the MODIS 500 m and VIIRS images. The results demonstrated that the approach can be successfully applied to MODIS 500 m and VIIRS images because the RAD significantly improved. The average RAD decreased to 9.39% in the MODIS 500 m image and to 12.84% in the VIIRS image. The relationship between the landscape of the algal bloom patch and the RAD showed that the performance of the LSMM method improved as the patch density (PD) increased from 0 to 2. When the perimeter-area ratio (PARA) is greater than 2 and the mean patch size (MPS) is less than approximately 5 km², the LSMM method significantly improved the RAD. An independent validation demonstrated that the LSMM method developed for MODIS and VIIRS images can be successfully applied to other coarser-resolution spatial imageries such as Geostationary Ocean Color Imager (GOCI) images. The LSMM method is more effective than the other methods for determining the fragmented landscape of algal blooms.     

SWATShare – A web platform for collaborative research and education through online sharing,simulation and visualization of SWAT models

Hydrologic models for a particular watershed or a region are created for addressing a specific research or management problem, and most of the models do not get reused after the project is completed. Similarly, multiple models may exist for a particular geographic location from different researchers or organizations. To avoid the duplication of efforts, and enable model reuse and enhancement through collaborative efforts, a prototype cyberinfrastructure, called SWATShare, is developed for sharing, execution and visualization of Soil and Water Assessment Tool (SWAT). The objective of this paper is to present the software architecture, functional capabilities and implementation of SWATShare as a collaborative environment for hydrology research and education using the models published and shared in the system. Besides the capability of publishing, sharing, discovery and downloading of SWAT models, some of the functions in SWATShare such as model calibration are supported by providing access to high performance computing resources including the XSEDE and cloud. Additionally, SWATShare can create dynamic spatial and temporal plots of model outputs at different scales. SWATShare can also be used as an educational tool within a classroom setting for comparing the hydrologic processes under different geographic and climatic settings. The utility of SWATShare for collaborative research and education is demonstrated by using three case studies. Even though this paper focuses on the SWAT model, the system’s architecture can be replicated for other models as well.