Using the technique of smooth filtering and cylindrical filtering,the initial vortex circulation and large-scale environmental field were separated from the background field.Then the separated initial vortex circulati...Using the technique of smooth filtering and cylindrical filtering,the initial vortex circulation and large-scale environmental field were separated from the background field.Then the separated initial vortex circulation was translated and reinserted in the location where it was observed.This led to the determination of a method of initial vortex relocation.For seven tropical cyclones at 23 points of measurement time in the years of 2006 and 2007,two schemes,either directly adding a tropical cyclone bogus model in the background or adding it after the relocation of the initial vortex in the background field,were employed.Simulation experiments were compared.The results showed that the mean errors of the simulated tropical cyclone tracks at 24 and 48 hours were both smaller with the scheme of adding tropical cyclone bogus model after the relocation of the initial vortex in the background field.The relocation method of the initial vortex decreases the error caused by the deviation of the initial tropical cyclone location in tropical cyclone models.The relocation method is conducive to improving the track forecast of tropical cyclone models and has a good perspective for operational application.展开更多
东北冷涡是影响我国东北地区天气和气候的重要环流系统。本文在前人研究工作基础上,构建了本文的东北冷涡识别与追踪方法。利用2000~2019年NCEP/NCAR再分析资料,对东北冷涡开展客观识别与追踪,进而分析东北冷涡的时空分布特征、持续时...东北冷涡是影响我国东北地区天气和气候的重要环流系统。本文在前人研究工作基础上,构建了本文的东北冷涡识别与追踪方法。利用2000~2019年NCEP/NCAR再分析资料,对东北冷涡开展客观识别与追踪,进而分析东北冷涡的时空分布特征、持续时间、强度和尺度等,最后利用国家地面气象站小时降水观测数据,探讨了东北冷涡影响期间东北区域的暖季降水分布特征。东北区域内,东北冷涡频数和影响天数无明显长期变化趋势,但存在明显的年际变化和月际变化,东北冷涡更易发生在暖季;东北冷涡的持续时间主要集中在48~72小时,半径尺度范围主要分布在600~1200 km,冷季平均尺度大于暖季,冷季冷涡中心强度也强于暖季;东北冷涡中心活动高频区沿45°~55°N呈东—西走向带状分布;东北冷涡影响期间的暖季降水量占比基本在20%以上,不同强度降水档(0.1~5 mm h^(-1),5~10 mm h^(-1),10~20 mm h^(-1)和≥20 mm h^(-1))中,占比空间分布不同,强降水局地性特征显著;东北冷涡影响期间的暴雨日降水量占比最大可超过70%。展开更多
基金Natural Science Foundation of China (9101501190715031+2 种基金40875026)Team Project of Foundation of Natural Science of Guangdong Province(8351030101000002)Project of Science and Technology of Guangdong Province(2008B030303025)
文摘Using the technique of smooth filtering and cylindrical filtering,the initial vortex circulation and large-scale environmental field were separated from the background field.Then the separated initial vortex circulation was translated and reinserted in the location where it was observed.This led to the determination of a method of initial vortex relocation.For seven tropical cyclones at 23 points of measurement time in the years of 2006 and 2007,two schemes,either directly adding a tropical cyclone bogus model in the background or adding it after the relocation of the initial vortex in the background field,were employed.Simulation experiments were compared.The results showed that the mean errors of the simulated tropical cyclone tracks at 24 and 48 hours were both smaller with the scheme of adding tropical cyclone bogus model after the relocation of the initial vortex in the background field.The relocation method of the initial vortex decreases the error caused by the deviation of the initial tropical cyclone location in tropical cyclone models.The relocation method is conducive to improving the track forecast of tropical cyclone models and has a good perspective for operational application.
文摘东北冷涡是影响我国东北地区天气和气候的重要环流系统。本文在前人研究工作基础上,构建了本文的东北冷涡识别与追踪方法。利用2000~2019年NCEP/NCAR再分析资料,对东北冷涡开展客观识别与追踪,进而分析东北冷涡的时空分布特征、持续时间、强度和尺度等,最后利用国家地面气象站小时降水观测数据,探讨了东北冷涡影响期间东北区域的暖季降水分布特征。东北区域内,东北冷涡频数和影响天数无明显长期变化趋势,但存在明显的年际变化和月际变化,东北冷涡更易发生在暖季;东北冷涡的持续时间主要集中在48~72小时,半径尺度范围主要分布在600~1200 km,冷季平均尺度大于暖季,冷季冷涡中心强度也强于暖季;东北冷涡中心活动高频区沿45°~55°N呈东—西走向带状分布;东北冷涡影响期间的暖季降水量占比基本在20%以上,不同强度降水档(0.1~5 mm h^(-1),5~10 mm h^(-1),10~20 mm h^(-1)和≥20 mm h^(-1))中,占比空间分布不同,强降水局地性特征显著;东北冷涡影响期间的暴雨日降水量占比最大可超过70%。
