[ Objective] The research aimed to study occurrence rule, reason and defense measures of the thunderstorm in Liaocheng in the past 50 years. [Method] By using meteorological observation records at 8 observatories of U...[ Objective] The research aimed to study occurrence rule, reason and defense measures of the thunderstorm in Liaocheng in the past 50 years. [Method] By using meteorological observation records at 8 observatories of Uaocheng during 1963 -2012, occurrence rule of the thunderstorm was studied. Occurrence reason and defense measures were also analyzed. [ Result] Annual thunderstorm days presented decreasing trend in Liaocheng. The earliest thunderstorm occurred in February, while the latest thunderstorm occurred in November. Thunderstorm mainly appeared in June, July and August, which occupied 77.6% of that in whole year. Thunderstorm days among each county had small difference. Thunderstorm days in Dong＇e County reached the minimum, which was related to local underlying surface. Occurrence reason of the thunderstorm was analyzed from objective and subjective aspects. By combining the actual situation of Liaocheng, corresponding prevention countermeasures were put forward. [Conclusion] The research could provide reference basis for thunderstorm disaster prevention and reduction in Liaocheng.展开更多
In order to avoid accidents due to aircraft icing, an algorithm for identifying supercooled water was studied. Specifically, a threshold method based on millimeter wave radar, lidar, and radiosonde was used to retriev...In order to avoid accidents due to aircraft icing, an algorithm for identifying supercooled water was studied. Specifically, a threshold method based on millimeter wave radar, lidar, and radiosonde was used to retrieve the coverage area of supercooled water and a fuzzy logic algorithm was used to classify the observed meteorological targets. The macrophysical characteristics of supercooled water could be accurately identified by combing the threshold method with the fuzzy logic algorithm. In order to acquire microphysical characteristics of supercooled water in a mixed phase, the unimodal spectral distribution of supercooled water was extracted from a bimodal or trimodal spectral distribution of a mixed phase cloud, which was then used to retrieve the effective radius and liquid water content of supercooled water by using an empirical formula. These retrieved macro- and micro-physical characteristics of supercooled water can be used to guide aircrafts during takeoff, flight, and landing to avoid dangerous areas.展开更多
文摘[ Objective] The research aimed to study occurrence rule, reason and defense measures of the thunderstorm in Liaocheng in the past 50 years. [Method] By using meteorological observation records at 8 observatories of Uaocheng during 1963 -2012, occurrence rule of the thunderstorm was studied. Occurrence reason and defense measures were also analyzed. [ Result] Annual thunderstorm days presented decreasing trend in Liaocheng. The earliest thunderstorm occurred in February, while the latest thunderstorm occurred in November. Thunderstorm mainly appeared in June, July and August, which occupied 77.6% of that in whole year. Thunderstorm days among each county had small difference. Thunderstorm days in Dong＇e County reached the minimum, which was related to local underlying surface. Occurrence reason of the thunderstorm was analyzed from objective and subjective aspects. By combining the actual situation of Liaocheng, corresponding prevention countermeasures were put forward. [Conclusion] The research could provide reference basis for thunderstorm disaster prevention and reduction in Liaocheng.
基金Supported by the Natural Science Foundation of Jiangsu Province(BK20170945)Open Fund of the Key Laboratory for Aerosol–Cloud–Precipitation of CMA–NUIST(KDW1703)+3 种基金National(Key)Basic Research and Development(973)Program of China(2014CB441405)National Natural Science Foundation of China(41275004,61372066,and 41571348)Startup Fund for Introduced Talents of the Nanjing University of Information Science&Technology(2016r028)Earth Science Virtual Simulation Experiment Teaching Course Construction Project(XNFZ2017C02)
文摘In order to avoid accidents due to aircraft icing, an algorithm for identifying supercooled water was studied. Specifically, a threshold method based on millimeter wave radar, lidar, and radiosonde was used to retrieve the coverage area of supercooled water and a fuzzy logic algorithm was used to classify the observed meteorological targets. The macrophysical characteristics of supercooled water could be accurately identified by combing the threshold method with the fuzzy logic algorithm. In order to acquire microphysical characteristics of supercooled water in a mixed phase, the unimodal spectral distribution of supercooled water was extracted from a bimodal or trimodal spectral distribution of a mixed phase cloud, which was then used to retrieve the effective radius and liquid water content of supercooled water by using an empirical formula. These retrieved macro- and micro-physical characteristics of supercooled water can be used to guide aircrafts during takeoff, flight, and landing to avoid dangerous areas.
