A"once-in-a-millennium"super rainstorm battered Zhengzhou,central China,from 07/17/2021 to 07/22/2021(named"7.20"Zhengzhou rainstorm).It killed 398 people and caused billions of dollars in damage.A...A"once-in-a-millennium"super rainstorm battered Zhengzhou,central China,from 07/17/2021 to 07/22/2021(named"7.20"Zhengzhou rainstorm).It killed 398 people and caused billions of dollars in damage.A pressing question is whether rainstorms of this intensity can be effectively documented by geological archives to understand better their historical variabilities beyond the range of meteorological data.Here,four land snail shells were collected from Zhengzhou,and weekly to daily resolved snail shellδ^(18)O records from June to September of 2021 were obtained by gas-source mass spectrometry and secondary ion mass spectrometry.The daily resolved records show a dramatic negative shift between 06/18/2021 and 09/18/2021,which has been attributed to the"7.20"Zhengzhou rainstorm.Moreover,the measured amplitude of this shift is consistent with the theoretical value estimated from the flux balance model and instrumental data for the"7.20"Zhengzhou rainstorm.Our results suggest that the ultra-high resolutionδ^(18)O of land snail shells have the potential to reconstruct local synoptic scale rainstorms quantitatively,and thus fossil snail shells in sedimentary strata can be valuable material for investigating the historical variability of local rainstorms under different climate backgrounds.展开更多
基金supported by the National Natural Science Foundation of China(42221003,4202530442103084)the Research Projects from the Chinese Academy of Sciences(XDB40000000)+1 种基金the Science and Technology Innovation Project of Laoshan Laboratory(LSKJ202203300)the CAS Youth Interdisciplinary Team。
文摘A"once-in-a-millennium"super rainstorm battered Zhengzhou,central China,from 07/17/2021 to 07/22/2021(named"7.20"Zhengzhou rainstorm).It killed 398 people and caused billions of dollars in damage.A pressing question is whether rainstorms of this intensity can be effectively documented by geological archives to understand better their historical variabilities beyond the range of meteorological data.Here,four land snail shells were collected from Zhengzhou,and weekly to daily resolved snail shellδ^(18)O records from June to September of 2021 were obtained by gas-source mass spectrometry and secondary ion mass spectrometry.The daily resolved records show a dramatic negative shift between 06/18/2021 and 09/18/2021,which has been attributed to the"7.20"Zhengzhou rainstorm.Moreover,the measured amplitude of this shift is consistent with the theoretical value estimated from the flux balance model and instrumental data for the"7.20"Zhengzhou rainstorm.Our results suggest that the ultra-high resolutionδ^(18)O of land snail shells have the potential to reconstruct local synoptic scale rainstorms quantitatively,and thus fossil snail shells in sedimentary strata can be valuable material for investigating the historical variability of local rainstorms under different climate backgrounds.
文摘针对移动机器人室内环境三维地图构建不齐帧、误差大和重建不佳等问题,提出激光雷达和RGB-Depth相机融合(camera radar net, CRN)方法,这是一种新的三维地图构建方法。在CRN中,提出一种雷达-视觉惯性里程计融合(Lidar-Visual Inertial Odometry via Smoothing and Mapping, LVIO-SAM)方法,该方法将优化估计二维移动平台空间位姿。然后通过误差卡尔曼滤波器(Error State Kalman Filter, ESKF)算法将空间位姿数据与轮式里程计进行动态优化,得到良好的建图效果。最后,使用移动机器人进行试验验证。试验结果显示,与激光雷达惯性里程计和视觉惯性里程计相比,所提方法在构建室内环境中,三维地图尺寸误差减少了22%,里程计精度提高了0.19%。
