城市地理空间、气候环境及交通系统间存在复杂的相互联系、相互制约的关系,交通及地理时空数据为理解三者间关系带来了新的机遇。城市轨道交通是居民绿色出行、缓解中国大城市交通拥堵的重要交通方式。深入研究影响城市地铁客流时间和空间分布变化的因素,有利于制定合理的土地利用及交通需求管理政策,也可为实时响应特定天气条件下旅客出行需求的变化和优化公交服务运营提供理论依据。论文使用智能交通卡数据,以南京市为例,通过建立一种季节性差分自回归移动平均(seasonal autoregressive integrated moving average with explanatory variables, SARIMAX)模型,解释不同种类的天气因素(如降雨、气温、相对湿度、风速等)对地铁客流量时空分布的影响程度。研究发现:降雨类因素在高峰和周末时段对地铁客流量的影响较大;各天气因素对各地铁站点客流量的影响大致呈现出从城市中心区域向外围区域逐渐变小的渐变式规律,且地铁无规律出行者比有规律出行者更易受恶劣天气因素的影响。 相似文献
The serpentinized peridotites overlying the subducted zones in the Izu-Bonin-Mariana (IBM) arc system have been interpret as the cause of the low-velocity layer identified beneath the IBM froearc, in turn few earthquakes occurred along the plate boundary. Chrysotile, which is a low temperature and highly hydrated phase of serpentine with low frictional strength, has been suggested as the low velocity material in the serpentinized peridotites, besides, brucite is inferred to be likely conducive to stable sliding. However, such idea encounters challenging in our serpentinized peridotites from the southern Mariana forearc, which absent both the above minerals. The presence of talc, which characterized by its weak, low-friction and inherently stable sliding behavior, provides new clue. Here we report the occurrence of talc in serpentinized peridotites collected from the landward trench slope of the southern Mariana forearc. We infer that talc is mainly forming as a result of the reaction of serpentine minerals with silica-saturated fluids released from the subducting slab, and talc also occurs as talc veins sometimes. Due to its unique physical properties, talc may therefore play a significant role in aseismic slip in the IBM subduction zone.