This article aims to study the history of scientific investigations in China in the nineteenth century,made by Russian scientists who ranged in status and position including official agents,the directors of the Russia...This article aims to study the history of scientific investigations in China in the nineteenth century,made by Russian scientists who ranged in status and position including official agents,the directors of the Russian Magneto-Meteorological Observatory in Beijing,the members of the Russian Orthodox Mission(ROM),and others.The article gives a detailed analysis of the unique expeditions of H.Fritsche(1839–1913),director of the Russian Magneto-Meteorological Observatory in Beijing,and Archimandrite Palladius(1817–1878),head of the ROM to the northeast part of China.During those expeditions,existing maps were corrected and new maps were made.The article also covers the history of natural science investigations,made by other members of missions,doctors,and attached persons.This article employs sources from Russian archives(Saint Petersburg Branch of the Archive of the Russian Academy of Sciences,Russian State Historical Archive,Archive of the Foreign Policy of the Russian Empire),which were rarely used by the scientific community,and adopts an empirical approach based on objectivity and historicism to the sources and research.展开更多
In recent years, locating total lightning at the VLF/LF band has become one of the most important directions in lightning detection. The Low-frequency E-field Detection Array(LFEDA) consisting of nine fast antennas wa...In recent years, locating total lightning at the VLF/LF band has become one of the most important directions in lightning detection. The Low-frequency E-field Detection Array(LFEDA) consisting of nine fast antennas was developed by the Chinese Academy of Meteorological Sciences in Guangzhou between 2014 and 2015. This paper documents the composition of the LFEDA and a lightning-locating algorithm that applies to the low-frequency electric field radiated by lightning pulse discharge events(LPDEs). Theoretical simulation and objective assessment of the accuracy and detection efficiency of LFEDA have been done using Monte Carlo simulation and artificial triggered lightning experiment, respectively. The former results show that having a station in the network with a comparatively long baseline improves both the horizontal location accuracy in the direction perpendicular to the baseline and the vertical location accuracy along the baseline. The latter results show that detection efficiencies for triggered lightning flashes and return strokes are 100% and 95%, respectively. The average planar location error for return strokes of triggered lightning flashes is 102 m. By locating LPDEs in thunderstorms, we find that LPDEs are consistent with convective regions as indicated by strong reflectivity columns, and present a reasonable distribution in the vertical direction.In addition, the LFEDA can reveal an image of lightning development through mapping the channels of lightning. Based on three-dimensional locations, the vertical propagation speed of the preliminary breakdown and the changing trend of the leader's speed in an intra-cloud and a cloud-to-ground flash are investigated. The research results show that the LFEDA has the capability for three-dimensional location of lightning, which provides a new technique for researching lightning development characteristics and thunderstorm electricity.展开更多
文摘This article aims to study the history of scientific investigations in China in the nineteenth century,made by Russian scientists who ranged in status and position including official agents,the directors of the Russian Magneto-Meteorological Observatory in Beijing,the members of the Russian Orthodox Mission(ROM),and others.The article gives a detailed analysis of the unique expeditions of H.Fritsche(1839–1913),director of the Russian Magneto-Meteorological Observatory in Beijing,and Archimandrite Palladius(1817–1878),head of the ROM to the northeast part of China.During those expeditions,existing maps were corrected and new maps were made.The article also covers the history of natural science investigations,made by other members of missions,doctors,and attached persons.This article employs sources from Russian archives(Saint Petersburg Branch of the Archive of the Russian Academy of Sciences,Russian State Historical Archive,Archive of the Foreign Policy of the Russian Empire),which were rarely used by the scientific community,and adopts an empirical approach based on objectivity and historicism to the sources and research.
基金supported by the National Natural Science Foundation of China(Grant Nos.41675005,91537290&41275008)the Basic Research Fund of Chinese Academy of Meteorological Sciences(Grant Nos.2016Z002&2015Z006)
文摘In recent years, locating total lightning at the VLF/LF band has become one of the most important directions in lightning detection. The Low-frequency E-field Detection Array(LFEDA) consisting of nine fast antennas was developed by the Chinese Academy of Meteorological Sciences in Guangzhou between 2014 and 2015. This paper documents the composition of the LFEDA and a lightning-locating algorithm that applies to the low-frequency electric field radiated by lightning pulse discharge events(LPDEs). Theoretical simulation and objective assessment of the accuracy and detection efficiency of LFEDA have been done using Monte Carlo simulation and artificial triggered lightning experiment, respectively. The former results show that having a station in the network with a comparatively long baseline improves both the horizontal location accuracy in the direction perpendicular to the baseline and the vertical location accuracy along the baseline. The latter results show that detection efficiencies for triggered lightning flashes and return strokes are 100% and 95%, respectively. The average planar location error for return strokes of triggered lightning flashes is 102 m. By locating LPDEs in thunderstorms, we find that LPDEs are consistent with convective regions as indicated by strong reflectivity columns, and present a reasonable distribution in the vertical direction.In addition, the LFEDA can reveal an image of lightning development through mapping the channels of lightning. Based on three-dimensional locations, the vertical propagation speed of the preliminary breakdown and the changing trend of the leader's speed in an intra-cloud and a cloud-to-ground flash are investigated. The research results show that the LFEDA has the capability for three-dimensional location of lightning, which provides a new technique for researching lightning development characteristics and thunderstorm electricity.
