空间分布因素对上海市住宅价格的影响研究

随着我国经济迅速发展,城市化现象加剧,城市资源化差异不断增大,城市之间内部结构的差距也在不断扩大,住宅商品所在地区的条件不同,特征价格也会有所不同。住宅价格受到多方面因素的影响,包括宏观方面和微观方面的因素,而且每个因素都具有一定的空间地理异质性。为研究上海市房价空间分布及其影响因素,本文运用Python、ArcGIS和Stata等软件,获取上海市12196个住宅小区的成交均价以及8000个POI,从微观角度,对住宅价格进行多角度分析,研究上海市住宅价格的空间分布特征,以乡镇级别为单位,构建普通最小二乘法(OLS)模型,得到影响因素对于上海市房价的影响程度的可视化分析结果。最后得出结论(1)上海市住宅价格空间聚集显著;(2)休闲娱乐场所的数量对于上海市住宅价格影响呈现正相关。

完工地区不同沙化等级草地优势群落空间分布格局的数字动态研究

通过对处于轻度沙化草地、中度沙化草地沙地和重度沙化草地等不同恢复演替阶段的群落的取样调查,研究了完工地区不同沙化等级草地植被群落优势种群的空间分布格局及其动态变化。运用扩散系数、聚集指数、平均拥挤度、聚块性指数、G reen指数、聚集强度等项指标,对群落优势种群分布格局的研究结果基本一致,大多数物种的空间分布呈显著的聚集分布。在演替进程中种群格局强度的变化和群落总体聚集程度的变化与种群动态和群落结构的空间异质性相对应,较高的聚集程度是种群分布斑块化和群落结构的空间异质性的反映,随着过渡进展,优势种的种群数量扩展,但种群分布的聚集强度下降,群落结构的空间异质性降低。

The spatial distribution of commuting CO_2 emissions and the influential factors:A case study in Xi'an,China

As the transport sector is a major source of greenhouse gas emissions, the effect of urbanization on transport CO2 emissions in developing cities has become a key issue under global climate change. Examining the case of Xi＇an, this paper aims to explore the spatial distribution of commuting CO2 emissions and influencing factors in the new, urban industry zones and city centers considering Xi＇an＇s transition from a monocentric to a polycentric city in the process of urbanization. Based on household survey data from 1501 respondents, there are obvious differences in commuting CO2 emissions between new industry zones and city centers： City centers feature lower household emissions of 2.86 kg CO2 per week, whereas new industry zones generally have higher household emissions of 3.20 kg CO2 per week. Contrary to previous research results, not all new industry zones have high levels of CO2 emissions; with the rapid development of various types of industries, even a minimum level of household emissions of 2.53 kg CO2 per week is possible. The uneven distribution of commuting CO2 emissions is not uniformly affected by spatial parameters such as job-housing balance, residential density, employment density, and land use diversity. Optimum combination of the spatial parameters and travel pattern along with corresponding transport infrastructure construction may be an appropriate path to reduction and control of emissions from commuting.

Spatial Distribution and Controlling Factors of Sedimentary Bodies in Jiaozhou Bay and Adjacent Sea Areas, Qingdao

The distributions of thickness of unconsolidated Quaternary sedimentary layers in Jiaozhou Bay and Qingdao offshore area were studied by using 1079-km high-resolution shallow seismic profiles and drilling core data, and the factors controlling the Quaternary evolution were discussed. The results show that such thickness distributions resulted from the coactions of geologic structures and marine hydrodynamic conditions since the Holocene. The geologic structures controlled the slope deposit, proluvial and fluvial fillings since the late Pleistocene. Holocene marine hydrodynamics eroded away sediments at the bay mouth, and tides carried these eroded materials to the sides of the bay mouth and released them there, forming channel-ridge-alternating geomorphic features. During transgressive processes, the sea level rose rapidly, and insufficient sediment supply and tidal actions yielded the relict sediments in the east of Qingdao offshore area.

Spatial Distribution and Environmental Determinants of Denitrification Enzyme Activity in Reed-Dominated Raised Fields

Denitrification is an important process of nitrogen removal in lake ecosystems.However,the importance of denitrification across the entire soil-depth gradients including subsurface layers remains poorly understood.This study aims to determine the spatial pattern of soil denitrification enzyme activity(DEA) and its environmental determinants across the entire soil depth gradients in the raised fields in Baiyang Lake,North China.In two different zones of the raised fields(i.e.,water boundary vs.main body of the raised fields),the soil samples from 1.0 m to 1.1 m depth were collected,and the DEA and following environmental determinants were quantified:soil moisture,p H,total nitrogen(TN),ammonia nitrogen(NH4+-N),nitrate nitrogen(NO3–-N),total organic carbon(TOC),and rhizome biomass of Phragmites australis.The results showed that the soil DEA and environmental factors had a striking zonal distribution across the entire soil depth gradients.The soil DEA reached two peak values in the upper and middle soil layers,indicating that denitrification are important in both topsoil and subsurface of the raised fields.The correlation analysis showed that the DEA is negatively correlated with the soil depth(p < 0.05).However,this phenomenon did not occur in the distance to the water edge,except in the upper layers(from 0.2 m to 0.7 m) of the boundary zone of the raised fields.In the main body of the raised fields,the DEA level remained high;however,it showed no significant relationship with the distance to the water edge.The linear regression analysis showed significant positive correlation of the DEA with the soil TN,NO3–-N,NH4+-N,and TOC;whereas it showed negative correlation with soil p H.No significant correlations with soil moisture and temperature were observed.A positive correlation was also found between the DEA and rhizome biomass of P.australis.

Spatial distribution rules and affecting factors of BIF in Anshan-Benxi area

A detailed investigation on 3D spatial distribution rules of Banded Iron-bearing Formation(BIF) with methods of gravity-magnetic inversion and 3D modeling of iron mine is presented based on the former analysis in the Anshan-Benxi area.Three dimension spatial distribution types of BIF are concluded as hook-like,tabularlike and "W"-like.BIF was mainly developed in three types of space including(1) the syncline cores,(2)cover coverage area,and(3) the deeper buried area where the range of tectonic uplift is small.The influences of tectonism,magmatic intrusion and uplift-erosion on the spatial distribution shapes of BIF are clarified.

Spatial distribution of surface energy fluxes over the Loess Plateau in China and its relationship with climate and the environment

China's Loess Plateau is located at the edge of the Asian summer monsoon in a transition zone of climate and ecology. In the Loess Plateau, climate and environments change along with space, which has an obvious impact on the spatial distribution of surface energy fluxes. Because of scarce land-surface observation sites and short observation time in this area, previous studies have failed to fully understand the land-surface energy balance characteristics over the entire the Loess Plateau and their effect mechanisms. In this paper, we first test the simulation ability of the Community Land Model(CLM) model by comparing its simulated data with observed data. Based on the simulation data for the Loess Plateau over the past thirty years, we then analyze the spatial distribution of surface energy fluxes and compare the pattern differences between the area averages for the driest year and wettest year. Furthermore, we analyze the relationship between the spatial distribution of the components of the surface energy balance with longitude, latitude, altitude, precipitation and temperature. The main results are as follows: the spatial distribution of surface energy fluxes are significantly different, with the surface net radiation and sensible heat flux increasing from south to north and latent heat flux and soil heat flux decreasing from southeast to northwest. The sensible heat flux at the driest point is nearly twice as high as that at the wettest point, whereas the latent heat flux and soil heat flux at the driest point are half as much as that at the wettest point. The impact of variations of annual precipitation on the components of the surface energy balance is also obvious, and the maximum magnitude of the changes to the sensible heat flux and latent heat flux is nearly 30%. To a certain extent, geographical factors(including longitude, latitude, and altitude) and climate factors(including temperature and precipitation) affect the surface energy fluxes. However, the surface net radiation is more closely related to latitude and altitude, sensible heat flux is more closely related to the monsoon rainfall and latitude, and latent heat flux and soil heat flux are more closely related to the monsoon rainfall.

Using Weights of Evidence in the Spatial Relation Between Infected Snails and Geographic Factors

Schistosomiasis is a serious public health problem in the middle-lower Yangtze River Basin in China. Study of spatial variation of snail distribution that is related to microgeographic factors can help to choose pertinent measures for snail extinguishment and environment rebuilding. This paper studied the theoretical architecture of weights-of-evidence approach. The case study was made for spatial relation between the occurrence of infected snails and geographic factor combinations in Waijiazhou marshland of Poyang Lake region in China. The multievidence data came from the geographical factor combinations by crossing operation of vegetation coverage grade layer, cattle route distance grade layer, and special environment layer (181 combinations in total) in GIS. The calculation of weight contrast index shows that high vegetation coverage, cattle route distance of <45 meters, and special geographic factor "ground depression" had direct spatial relation with the occurrence of infected snails. The verification by crossing operation in GIS indicated 72.45% of the infected snails concentrated on the areas of positive weight contrast index (sequenced in an order of weight contrast index from high to low), demonstrating the high efficiency of the model established in finding infected snails according to the geographic factor combinations that can be explicitly discerned in the study area.