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建成环境对出租车出行需求影响的时空间分异模式 被引量:6
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作者 谢蔚翰 周素红 《现代城市研究》 CSSCI 2018年第12期22-29,共8页
出租车作为城市重要的公共交通工具,在满足居民日常出行需求、提高出行效率方面的作用举足轻重。已有研究分析了城市建成环境对居民出租车出行需求影响的空间异质性,但受限于交通大数据的可获取性,尚未考虑到该影响在时间维度上的差异,... 出租车作为城市重要的公共交通工具,在满足居民日常出行需求、提高出行效率方面的作用举足轻重。已有研究分析了城市建成环境对居民出租车出行需求影响的空间异质性,但受限于交通大数据的可获取性,尚未考虑到该影响在时间维度上的差异,而研究时空差异恰恰可为制定更符合居民出行需求的城市交通系统规划、日常管理与决策以及智慧城市建设等提供参考依据因此本文考察了在时间维度下,建成环境对出租车出行需求影响机制的时空特征与模式。结果发现,人口密度的影响在外围地区具有全天候的正向作用,而在城市内部则一直呈现负向影响且随时间推移,影响的"负值中心"逐渐西移;就业岗位密度的影响在全域空间上均为正向影响强度由中心向外围地区逐渐增强,且随时间推移影响的强弱区域范围发生融合与重组;土地利用混合度的影响强度较大,作用机制与所处地区的中心地级别有关,但时间维度上的差异不明显;道路网密度在全域均具有正向影响作用,且外环路以内地区为全天候影响较弱的区域晩高峰时间段出现"双弱中心"的时空演变格局。最后通过聚类发现,人口密度主导影响的地区全天都分布在城市边缘地带,就业岗位密度与之相似;土地利用混合度主导影响的地区从早至晚有从中心城区向外扩散的趋势,且呈现中心地区负向作用、外围地区正向作用的影响机理;道路网密度主导影响的地区在不同时间段呈现跃迁与扩张变化,经历了从郊区到中心区再回到外围生态休闲用地上的过程。 展开更多
关键词 出租车出行需求 时空间分异 地理加权泊松回归
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Investigation of the Macroscopic Anomalies before and after the M8. 0 Wenchuan Earthquake
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作者 Zhang Xiaotao Zhang Yongxian Xu Dunhuan 《Earthquake Research in China》 2010年第1期48-69,共22页
The macroscopic anomalies before and after the May 12,2008 Wenchuan M8. 0 earthquake were collected and analyzed in this paper. The credible anomalies occurring from February 1 to June 10,2008 were treated as macrosco... The macroscopic anomalies before and after the May 12,2008 Wenchuan M8. 0 earthquake were collected and analyzed in this paper. The credible anomalies occurring from February 1 to June 10,2008 were treated as macroscopic anomalies,and their space-time distribution was studied. The research indicates that in time distribution,the number of macroscopic anomalies peaked before the earthquake,and these peak values appeared twice after the earthquake. In space distribution,the distribution of macroscopic anomalies before the earthquake was the same as that after the earthquake. In this paper,the mechanism of occurrence of macroscopic anomalies and the role of macroscopic anomalies in forecasting earthquake were also discussed. 展开更多
关键词 Wenchuan earthquake Macroscopic anomaly Statistical analysis Space-time distribution
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Variation of temporal and spatial patterns of NO_2 in Beijing using OMI and mobile DOAS 被引量:5
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作者 Ang Li Jie Zhang +6 位作者 Pinhua Xie Zhaokun Hu Jin Xu Fusheng Mou Fengcheng Wu Jianguo Liu Wenqing Liu 《Science China Chemistry》 SCIE EI CAS CSCD 2015年第9期1367-1376,共10页
Control policies such as "odd-and-even license plate rule" were implemented by the Chinese government to restrict traffic and suspend factory production in Beijing and neighboring cities during the Asia-Paci... Control policies such as "odd-and-even license plate rule" were implemented by the Chinese government to restrict traffic and suspend factory production in Beijing and neighboring cities during the Asia-Pacific Economic Cooperation summit. We use ozone monitoring instrument(OMI), mobile differential optical absorption spectroscopy(DOAS), and multi-axis differential optical absorption spectroscopy(MAX-DOAS) to measure the variation of the spatial and temporal patterns of NO2 column densities from October 24, 2014 to November 22, 2014. It is found that the NO2 column densities during the episode of control policies are significantly lower than those during other periods, and the emission flux of NO2 calculated by mobile DOAS is also lower than the results from other periods. Some daily low NO2 column densities occur with the northwest wind direction. We then compare the relationship between OMI and mobile DOAS NO2 column density observations, and the results of mobile DOAS are approximately 2.7 times larger than the OMI values. The largest discrepancy occurs in the northern part of Beijing city. In other parts, the two instruments have a better correlation coefficient(R2) of 0.61. The low NO2 column densities that occur during the episode of control policies are affected by the control policies as well as meteorological conditions. 展开更多
关键词 OMI DOAS NO2 emission flux control policies
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