Identification Of Spatial Variations Research Articles

Identification of spatial variation in road network and its driving patterns: Economy and population

China is a globally important ecosystem that is undergoing rapid development and land use/cover change (LUCC). The role of road networks in the LUCC is becoming increasingly important. Much of the upgrading in road networks is propelled by economy and population growth. However, the relationships between the road networks and the social-economic factors are poorly understood by using the ordinary least squares (OLS) regression, which assumes that the estimated beta value holds the same everywhere within a given study area. To determine whether there is spatial variation in the relationship between the road networks and the social-economic drivers in a given region, we employed a local model, geographically weighted regression (GWR), that provides a regression coefficient (beta) for each sample location within the study area. Taking Fujian Province, one of the most developed regions in China, as a case, this paper firstly employed an Exploratory Spatial Data Analysis (ESDA) to identify the spatial patterns of the road networks at the different sizes of sampling units. We found that the spatial distribution of road networks had an obvious tendency toward the geographical dependency, with High-High clusters seated in the eastern coastal areas and Low-Low clusters distributed dispersedly in the study area. The spatial patterns of the road networks had highly consistency in the different sizes of sample units. Then, the GWR model confirmed that the relationships between the road networks and the socioeconomic factors varied by locations, with multiple relationships (both synergy and tradeoff) between them coexisting in the study region. These relationships were also visualized by sign and magnitude of the estimated coefficients of GWR for each sampling unit, which allow us to compare the different effects of the dependent variables on the road networks across locations. We also found that the variable of gross domestic product density (GDPD) is a preferred indicator over the variable of population density (PD) to analyze the associations with the road networks. Thus, this study provided useful information to develop differentiated strategies for road development at the finer level by using the more nuanced GWR models.

Impact of environmental factors on water quality at multiple spatial scales and its spatial variation in Huai River Basin, China

Quantitative assessment of water quality and its spatial variation identification, as well as the discernment of primary factors affecting water quality are in its urgent in water environment management. In this study, four key water quality indicators, namely, ammonia nitrogen (NH4+-N), permanganate index (CODMn), total phosphorus (TP) and total nitrogen (TN) at 71 sampling sites were selected to evaluate water quality and its spatial variation identification. More concerns were emphasized on the anthropogenic factors (land use pattern) and natural factors (river density, elevation and precipitation) to quantify the overall water quality variations at different spatial scales. Results showed that the Yi-Shu-Si River sub-basin had a better water quality status than the Huai River sub-basin. The moderate polluted area nearly distributed in the upper and middle reaches of the Shaying River and Guo River. The high cluster centers which were surrounded with CODMn, NH4+-N, TN and TP mainly also distributed in the upper and middle reaches of the Shaying River and Guo River. Redundancy analysis showed that the 200 m buffer area acted as the most sensitive area, which was easily subjected to pollution. The precipitation was identified as the most important variables among all the studied hydrological units, followed by farmland, urban land or elevation. The point source pollution was still existed although the non-point source pollution was also identified. The urban surface runoff pollution was severer than farmland fertilizer loss at the sub-basin scale in flood season, while the farmland showed “small-scale” effects for explaining overall water quality variations. This research is helpful for identifying the overall water quality variations from the scale-process interactions and providing a scientific basis for pollution control and decision making for the Huai River Basin.

Enhancing China’s National Image Through Culture Festivals: A Case Study of China Culture Years in Europe

Since the mid-2000s, the PRC has increasingly focused on pursuing cultural diplomacy abroad to improve its national image and enhance cultural soft power. Although China’s cultural “Charm Offensive” has not gone unnoticed, a variety of specific activities have not been subject to research so far. This paper, therefore, attempts to fill this research gap by analyzing Chinese state-level cultural diplomacy through a comparative case study of three China Culture Year events held in France (2004), Italy (2010), and Germany (2012). These findings are subsequently compared to the China Culture Year in Australia (2012), thereby allowing the identification of spatial variations. I argue that the Chinese government applies a general approach of organizing the events abroad by making use of local institutions. At the same time, through the strategic selection of events, the festivals portray distinct national images that transmit particular narratives of self-presentation to the European audience and take into account country-specific preferences.

Gender Differences in Chronic Exposure to Traffic-Related Air Pollution—A Simulation Study of Working Females and Males*

The objective of this study was to identify spatial variability in exposure to outdoor traffic-related air pollution with specific emphasis on comparing exposure estimates for working females and males across a metropolitan area. A spatial exposure simulation model was used to estimate annual average exposure to traffic-related nitrogen dioxide for males and females reporting regular work in census tracts other than that of their residence, in Vancouver, British Columbia. The model produced estimates of annual average exposure in six microenvironments (home indoor, work indoor, other indoor, outdoor, in-vehicle to work, and in-vehicle other) using time-activity patterns and work flow data, for males and females in each of 382 census tracts. This allowed for the identification of spatial variations in exposure estimates for each gender, due to mobility within the study region. Indoor sources of nitrogen dioxide were not included in the simulation. No significant differences in estimated total exposure were found between working females and males in general. Small but observable spatial differences, however, were found between working females and males at the 90th percentile of the exposure distributions associated specifically with the work indoor microenvironment. These were highest in suburban areas (+3 μ g/m3 for females, relative to total exposures in the range of 26 to 37 μ g/m3 annual average hourly nitrogen dioxide). These results identify specific geographic locations in the study area where personal monitoring studies might be warranted and suggest that the inclusion of workplace locations in multivariate modeling could be useful to further understand differences in estimated exposures.

Spatial and temporal variation in trace elemental fingerprints of mytilid mussel shells: A precursor to invertebrate larval tracking

Elements incorporated into developing hard parts of planktonic larvae record the environmental conditions experienced during growth. These chemical signatures, termed elemental fingerprints, potentially allow for reconstruction of locations of larvae. Here, we have demonstrated for the first time the feasibility of this approach for bivalve shells. We have determined the spatial scale over which we are able to discriminate chemical signatures in mussels in southern California and characterized the temporal stability of these signals. Early settlers of Mytilus californianus and Mytilus galloprovincialis were collected from eight sites in southern California. Shells were analyzed for nine isotopes using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). We discriminated among mussels collected in two bays and the open coast using Mn, Pb, and Ba shell concentrations. Shell concentrations of Pb and Sr were sufficiently different to discriminate between mussels from the northern and southern regions of the open coast, each representing approximately 20 km of coastline. These signals were relatively stable on monthly and weekly time scales. These results indicate that trace elemental fingerprinting of shell material is a promising technique to track bivalve larvae moving between bays and the open coast or over along-shore scales on the order of 20 km. Identification of spatial variation in elemental fingerprints that is stable over time represents a crucial step in enhancing our ability to understand larval transport and population connectivity in invertebrates.

Pumping tests in networks of multilevel sampling wells: Motivation and methodology

The identification of spatial variations in hydraulic conductivity (K) on a scale of relevance for transport investigations has proven to be a considerable challenge. Recently, a new field method for the estimation of interwell variations in K has been proposed. This method, hydraulic tomography, essentially consists of a series of short‐term pumping tests performed in a tomographic‐like arrangement. In order to fully realize the potential of this approach, information about lateral and vertical variations in pumping‐induced head changes (drawdown) is required with detail that has previously been unobtainable in the field. Pumping tests performed in networks of multilevel sampling (MLS) wells can provide data of the needed density if drawdown can accurately and rapidly be measured in the small‐diameter tubing used in such wells. Field and laboratory experiments show that accurate transient drawdown data can be obtained in the small‐diameter MLS tubing either directly with miniature fiber‐optic pressure sensors or indirectly using air‐pressure transducers. As with data from many types of hydraulic tests, the quality of drawdown measurements from MLS tubing is quite dependent on the effectiveness of well development activities. Since MLS ports of the standard design are prone to clogging and are difficult to develop, alternate designs are necessary to ensure accurate drawdown measurements. Initial field experiments indicate that drawdown measurements obtained from pumping tests performed in MLS networks have considerable potential for providing valuable information about spatial variations in hydraulic conductivity.