An analysis is made to investigate the structure features of the extensive heavy rainfall left by typhoon Matsa, after its landfall in China's Mainland in August 2005, based on a range of observational results, in...An analysis is made to investigate the structure features of the extensive heavy rainfall left by typhoon Matsa, after its landfall in China's Mainland in August 2005, based on a range of observational results, including surface intensive observation data, TBB data from China's FY-2 satellite, and NCEP 1°×1° reanalysis data. The study tries to explore the interaction between atmospheric waves, 3-D atmospheric structures, and typhoon rainbands. Observational facts, diagnostic analysis, and atmospheric wave theory are used to look into the formation mechanism of distant typhoon rainbands. Results show that (1) Matsa rainbands have the features of noticeable wave train distribution and long distance propaga-tion; (2) the typhoon rainbands extend as far as 2000 km northwardly from the typhoon center, with a wavelength of 500―1000 km and a wave period of 12―24 h; (3) the wave structure of Matsa rainbands is closely associated with the corresponding wave variation of the ambient 3-D atmospheric structures, including disturbance vorticity, divergence field, vertical motion field, water vapor flux divergence field, etc. (4) both observational facts and theoretical analysis show that the northward extending typhoon rainbands are associated with the mixed effects of atmospheric inertia wave and internal gravity wave; (5) only under proper atmospheric stratification and vertical wavenumber of gravity wave, can a ty-phoon stimulate such a wave being able to reach such a distance, and result in extending wavy rain-bands.展开更多
Here we use a Discriminant Genetic Algorithm Extended (DGAE) model to diagnose and predict seasonal sand and dust storm (SDS) activities occurring in Northeast Asia. The study employed the regular meteorological data,...Here we use a Discriminant Genetic Algorithm Extended (DGAE) model to diagnose and predict seasonal sand and dust storm (SDS) activities occurring in Northeast Asia. The study employed the regular meteorological data, including surface data, upper air data, and NCEP reanalysis data, collected from 1980–2006. The regional, seasonal, and annual differences of 3-D atmospheric circulation structures and SDS activities in the context of spatial and temporal distributions were given. Genetic algorithms were introduced with the further extension of promoting SDS seasonal predication from multi-level resolution. Genetic probability was used as a substitute for posterior probability of multi-level discriminants, to show the dual characteristics of crossover inheritance and mutation and to build a non-linear adaptability function in line with extended genetic algorithms. This has unveiled the spatial distribution of the maximum adaptability, allowing the forecast field to be defined by the population with the largest probability, and made discriminant genetic extension possible. In addition, the effort has led to the establishment of a regional model for predicting seasonal SDS activities in East Asia. The model was tested to predict the spring SDS activities occurring in North China from 2007 to 2009. The experimental forecast resulted in highly discriminant intensity ratings and regional distributions of SDS activities, which are a meaningful reference for seasonal SDS predictions in the future.展开更多
An atmosphere watersphere disaster reduction system(AWDRS), which is mainly aimed at serious disasters, such as heavy rainstorms, floods and typhoons, is presented. The system took us six years to establish. It has b...An atmosphere watersphere disaster reduction system(AWDRS), which is mainly aimed at serious disasters, such as heavy rainstorms, floods and typhoons, is presented. The system took us six years to establish. It has been put in real time operation and proved beneficial both economically and socially. AWDRS consists of five sub systems, i.e., Disaster Pre warning System(DPS), Disaster Reduction Information System(DRIS), Database & Disaster Assessment System(DDAS), Disaster Reduction Countermeasure System(DRCS) and Local Demonstrating System(LDS). Through several years of operation, the system has brought about an economic benefit of more than one billion yuan, as well as notable social benefits. Its establishment has laid a good foundation for the construction of China’s National Disaster Preventing & Reducing System(CNDPRS) and the setting up of China’s National Disaster Reduction Center(CNDRC). The system has been awarded a first prize of CAS and a national prize.展开更多
基金Supported by the National Grand Fundamental Research 973 Program of China (Grant No. 2004CB418301)the National Natural Science Foundation of China (Grant Nos. 40675033, 40575018 and 40505009)
文摘An analysis is made to investigate the structure features of the extensive heavy rainfall left by typhoon Matsa, after its landfall in China's Mainland in August 2005, based on a range of observational results, including surface intensive observation data, TBB data from China's FY-2 satellite, and NCEP 1°×1° reanalysis data. The study tries to explore the interaction between atmospheric waves, 3-D atmospheric structures, and typhoon rainbands. Observational facts, diagnostic analysis, and atmospheric wave theory are used to look into the formation mechanism of distant typhoon rainbands. Results show that (1) Matsa rainbands have the features of noticeable wave train distribution and long distance propaga-tion; (2) the typhoon rainbands extend as far as 2000 km northwardly from the typhoon center, with a wavelength of 500―1000 km and a wave period of 12―24 h; (3) the wave structure of Matsa rainbands is closely associated with the corresponding wave variation of the ambient 3-D atmospheric structures, including disturbance vorticity, divergence field, vertical motion field, water vapor flux divergence field, etc. (4) both observational facts and theoretical analysis show that the northward extending typhoon rainbands are associated with the mixed effects of atmospheric inertia wave and internal gravity wave; (5) only under proper atmospheric stratification and vertical wavenumber of gravity wave, can a ty-phoon stimulate such a wave being able to reach such a distance, and result in extending wavy rain-bands.
基金supported by National S & T Support Program (Grant No. 2008BAC40B02)National Basic Research Program of China (Grant Nos. 2006CB403703 and 2006CB403701)Basic Research Fund under Chinese Academy of Meteorological Sciences (Grant Nos. 2009Y002, 2009Y001)
文摘Here we use a Discriminant Genetic Algorithm Extended (DGAE) model to diagnose and predict seasonal sand and dust storm (SDS) activities occurring in Northeast Asia. The study employed the regular meteorological data, including surface data, upper air data, and NCEP reanalysis data, collected from 1980–2006. The regional, seasonal, and annual differences of 3-D atmospheric circulation structures and SDS activities in the context of spatial and temporal distributions were given. Genetic algorithms were introduced with the further extension of promoting SDS seasonal predication from multi-level resolution. Genetic probability was used as a substitute for posterior probability of multi-level discriminants, to show the dual characteristics of crossover inheritance and mutation and to build a non-linear adaptability function in line with extended genetic algorithms. This has unveiled the spatial distribution of the maximum adaptability, allowing the forecast field to be defined by the population with the largest probability, and made discriminant genetic extension possible. In addition, the effort has led to the establishment of a regional model for predicting seasonal SDS activities in East Asia. The model was tested to predict the spring SDS activities occurring in North China from 2007 to 2009. The experimental forecast resulted in highly discriminant intensity ratings and regional distributions of SDS activities, which are a meaningful reference for seasonal SDS predictions in the future.
文摘An atmosphere watersphere disaster reduction system(AWDRS), which is mainly aimed at serious disasters, such as heavy rainstorms, floods and typhoons, is presented. The system took us six years to establish. It has been put in real time operation and proved beneficial both economically and socially. AWDRS consists of five sub systems, i.e., Disaster Pre warning System(DPS), Disaster Reduction Information System(DRIS), Database & Disaster Assessment System(DDAS), Disaster Reduction Countermeasure System(DRCS) and Local Demonstrating System(LDS). Through several years of operation, the system has brought about an economic benefit of more than one billion yuan, as well as notable social benefits. Its establishment has laid a good foundation for the construction of China’s National Disaster Preventing & Reducing System(CNDPRS) and the setting up of China’s National Disaster Reduction Center(CNDRC). The system has been awarded a first prize of CAS and a national prize.
