新一代重力卫星计划主要依靠高精度星载加速度计(ACC)、星间测距系统(KBR)或星载梯度计(SGG)进行地球重力场探测。搭载高精度星载GPS接收机的低轨卫星(low earth orbit,LEO)可以相对较低成本获取LEO卫星的精密轨道。卫星精密轨道一方面...新一代重力卫星计划主要依靠高精度星载加速度计(ACC)、星间测距系统(KBR)或星载梯度计(SGG)进行地球重力场探测。搭载高精度星载GPS接收机的低轨卫星(low earth orbit,LEO)可以相对较低成本获取LEO卫星的精密轨道。卫星精密轨道一方面服务于LEO的主任务(如遥感、气象等);另一方面可以将这类LEO卫星和星座综合起来,构成LEO星群LEO星群精密轨道数据包含的丰富地球重力场信息为获取地球重力场的时变信息提供可能。本文给出一种利用LEO星群精密轨道数据反演地球重力场低阶带谐系数时变信息的实用方法——交叠点法,该方法可有效消弱非保守力等因素对重力场反演的影响。然后,以COSMIC(constellation observing system for meteorology ionosphere&climate)为实例分析LEO星群交叠点的覆盖特性,径向轨道精度对交叠点法的影响。最后进行低阶带谐系数(C02和C03)时变信号的模拟计算,并对结果进行分析。展开更多
The global trend towards urbanisation explains the growing interest in the study of the modification of the urban climate due to the heat island effect and global warming, and its impact on enersy use of buildings. Al...The global trend towards urbanisation explains the growing interest in the study of the modification of the urban climate due to the heat island effect and global warming, and its impact on enersy use of buildings. Also urban comfort, health and durability, referring respectively to pedestrian wind/ thermal comfort, pollutant dispersion and wind-driven rain are of interest. Urban Physics is a well- established discipline, incorporating relevant branches of physics, environmental chemistry, aerodynamics, meteorolosy and statistics. Therefore, Urban Physics is well positioned to provide keycontributions to the current urban problems and challenges. The present paper addresses the role of Urban Physics in the study of wind comfort, thermal comfort, energy demand, pollutant dispersion and wind-driven rain. Furthermore, the three major research methods applied in Urban Physics, namely field experiments, wind tunnel experiments and numerical simulations are discussed. Case studies illustrate the current challenges and the relevant contributions of Urban Physics.展开更多
文摘新一代重力卫星计划主要依靠高精度星载加速度计(ACC)、星间测距系统(KBR)或星载梯度计(SGG)进行地球重力场探测。搭载高精度星载GPS接收机的低轨卫星(low earth orbit,LEO)可以相对较低成本获取LEO卫星的精密轨道。卫星精密轨道一方面服务于LEO的主任务(如遥感、气象等);另一方面可以将这类LEO卫星和星座综合起来,构成LEO星群LEO星群精密轨道数据包含的丰富地球重力场信息为获取地球重力场的时变信息提供可能。本文给出一种利用LEO星群精密轨道数据反演地球重力场低阶带谐系数时变信息的实用方法——交叠点法,该方法可有效消弱非保守力等因素对重力场反演的影响。然后,以COSMIC(constellation observing system for meteorology ionosphere&climate)为实例分析LEO星群交叠点的覆盖特性,径向轨道精度对交叠点法的影响。最后进行低阶带谐系数(C02和C03)时变信号的模拟计算,并对结果进行分析。
文摘The global trend towards urbanisation explains the growing interest in the study of the modification of the urban climate due to the heat island effect and global warming, and its impact on enersy use of buildings. Also urban comfort, health and durability, referring respectively to pedestrian wind/ thermal comfort, pollutant dispersion and wind-driven rain are of interest. Urban Physics is a well- established discipline, incorporating relevant branches of physics, environmental chemistry, aerodynamics, meteorolosy and statistics. Therefore, Urban Physics is well positioned to provide keycontributions to the current urban problems and challenges. The present paper addresses the role of Urban Physics in the study of wind comfort, thermal comfort, energy demand, pollutant dispersion and wind-driven rain. Furthermore, the three major research methods applied in Urban Physics, namely field experiments, wind tunnel experiments and numerical simulations are discussed. Case studies illustrate the current challenges and the relevant contributions of Urban Physics.
