Based on the conventional observation data,daily reanalysis data from NCAR/NCEP,and TBB data derived from FY-2G infrared cloud images in April 2018,a heavy snowfall weather process in central Inner Mongolia from April...Based on the conventional observation data,daily reanalysis data from NCAR/NCEP,and TBB data derived from FY-2G infrared cloud images in April 2018,a heavy snowfall weather process in central Inner Mongolia from April 4 to 6 in 2018 was analyzed.The results show that the low trough at 500 hPa,the southerly wind jet stream at 700 hPa,and the inverted trough on the ground were the main influencing systems causing this blizzard.The transportation of warm and humid air by the southerly wind jet stream at 700 hPa and intense water vapor convergence provided sufficient water vapor conditions for the blizzard,and the moist layer in the blizzard area was deep.The low-level MPV in the blizzard area was<0,and the atmosphere was in a conditional symmetric instability state.The coupling of the upper and lower-level jets induced strong ascending motion.With the invasion of cold air,a low-level cold pad was formed,so that the warm and humid air tilted upward.The secondary circulation updraft triggered by the wet Q vector system released the conditional symmetric instability energy,so that the sloping motion was more intense,and the heavy snowfall appeared.Meanwhile,there was a good correspondence relationship between the blizzard area and the large-value area of low-level wet Q vector divergence.The mesoscale cloud clusters continuously generating,merging,and moving eastward in Hetao area were the direct cause of this blizzard,and the TBB of the cloud clusters was≤-56℃.The blizzard happened in the the edge gradient and large-value area of TBB.展开更多
In this paper, time and space distribution regularity of meso-scale heavy rains in five selected typhoons which landed at Fujian from 1996 to 1998 has been analyzed. Besides, with hourly digitized satellite infrared i...In this paper, time and space distribution regularity of meso-scale heavy rains in five selected typhoons which landed at Fujian from 1996 to 1998 has been analyzed. Besides, with hourly digitized satellite infrared imagery, the features of the mesoscale are revealed for the genesis and evolution of mesoscale convective systems in typhoons. It indicates that the intensity of mesoscale storms is closely connected with the temperature and the area of the coldest cloud cluster. The heavy rainfall usually emerges on the eastern side of the mesoscale convective cloud clusters, where the cloud mass is developing and with a dense gradient and big curvature of isoline of the cloud top temperature.展开更多
Activities of tropical cyclones(TCs)over the Bay of Bengal(BoB)often exert appreciable influences on precipitation in China,but how and to what extent these influences operate remain unclear.This study utilizes the In...Activities of tropical cyclones(TCs)over the Bay of Bengal(BoB)often exert appreciable influences on precipitation in China,but how and to what extent these influences operate remain unclear.This study utilizes the International Best Track Archive for Climate Stewardship(IBTrACS)dataset and infrared satellite images from Japan during1996-2021 to analyze the cloud system structure patterns associated with BoB TCs(excluding tropical depressions)and their impact on China rainfall.A fuzzy c-means clustering method was employed to classify TC cloud clusters into three morphological types:Type“6”(T6)and Type“9”(T9),with cloud distributions predominantly located north(south)of the TC center;and type“symmetry”(TSM),with relatively balanced cloud distributions on both sides.The results indicate that T6(41.3%)occurs most frequently in autumn,T9(31.2%)peaks in early summer,and TSM(27.5%)also shows a slight preference for autumn.Distinct circulation features are associated with each type.At 500 hPa over the Qinghai-Xizang Plateau(QXP),T6 is associated with the southern branch trough,T9 with straight westerlies,and TSM with a ridge.At 200 hPa,both centers of T6 and TSM are located at the periphery of the South Asian high(SAH),with enhanced upper-level divergence outflows,resulting in northward extension of cloud clusters under the influence of the westerly jet.In contrast,T9 TCs are embedded within the SAH,where weaker divergence outflows restrict northward cloud development.All three types are characterized by a column-integrated water vapor channel extending from the BoB to southern China,with T9 exhibiting the strongest moisture transport to China.Precipitation analyses reveal that all three types contribute to rainfall in Yunnan Province and the Guangxi Zhuangzu Zizhiqu.Moreover,T6 produces heavier rainfall in southern Xizang Zizhiqu(abbreviated as Xizang hereafter),T9 in Yunnan Province,and TSM in Sichuan Province and Xizang.Remote precipitation induced by TC longdistance moisture transport also exhibits distinct patterns:under T6,high-rainfall areas are widely distributed across southwestern China and parts of southern China;under T9,heavy rainfall is concentrated in southern China;and under TSM,heavy rainfall is mainly confined to Guangdong and Jiangxi provinces.These results provide useful insights for precipitation forecasting in China based on the cloud cluster patterns of the BoB TCs.展开更多
Eastward-moving cloud clusters from the Tibetan Plateau(TP)often trigger heavy rainfall events in the Yangtze River basin in summer.Forecasting these events in an operational environment remains a challenging task.Her...Eastward-moving cloud clusters from the Tibetan Plateau(TP)often trigger heavy rainfall events in the Yangtze River basin in summer.Forecasting these events in an operational environment remains a challenging task.Here,dynamical diagnosis and a Lagrangian trajectory model are used to analyze the background atmospheric circulation,maintenance mechanism,and moisture transport of two Meiyu front rainstorms(MYFR)during 30 June-2 July 2016 and 17-19 June 2018 associated with eastward-moving cloud clusters from the TP.It is shown that in both cases heavy rainfall is characterized by semi-continuous rainbelts extending from the eastern TP to the Yangtze River valleys with eastward-spreading convective clouds weakening and strengthening alternately from the eastern TP to downstream regions.Following the track of positive water vapor advection,centers of positive vorticity propagate downstream through the Sichuan basin.The baroclinic thermodynamic–dynamical interaction and the barotropic nonequilibrium force work against each other in the development of the MYFR.Specifically,during the early stage of precipitation development,the barotropic non-equilibrium force dominates,while during the period of heavy precipitation the baroclinic thermodynamic-dynamical interaction dominates.The convergence associated with the baroclinic thermodynamic-dynamical interaction guarantees the persistence of heavy precipitation.Compared to the climate mean state(1988-2018),both MYFR events associated with eastward-moving cloud clusters from the eastern TP are characterized by increased moisture transport from the southwest.One of the major paths of moisture transport in both cases is along the south side of the TP,directly connected to the eastward movement of cloud clusters.展开更多
Traditional spatial clustering methods have the disadvantage of ＂hardware division＂, and can not describe the physical characteristics of spatial entity effectively. In view of the above, this paper sets forth a gen...Traditional spatial clustering methods have the disadvantage of ＂hardware division＂, and can not describe the physical characteristics of spatial entity effectively. In view of the above, this paper sets forth a general multi-dimensional cloud model, which describes the characteristics of spatial objects more reasonably according to the idea of non-homogeneous and non-symmetry. Based on infrastructures＇ classification and demarcation in Zhanjiang, a detailed interpretation of clustering results is made from the spatial distribution of membership degree of clustering, the comparative study of Fuzzy C-means and a coupled analysis of residential land prices. General multi-dimensional cloud model reflects the integrated char- acteristics of spatial objects better, reveals the spatial distribution of potential information, and realizes spatial division more accurately in complex circumstances. However, due to the complexity of spatial interactions between geographical entities, the generation of cloud model is a specific and challenging task.展开更多
Cloud computing has developed as an important information technology paradigm which can provide on-demand services. Meanwhile,its energy consumption problem has attracted a grow-ing attention both from academic and in...Cloud computing has developed as an important information technology paradigm which can provide on-demand services. Meanwhile,its energy consumption problem has attracted a grow-ing attention both from academic and industrial communities. In this paper,from the perspective of cloud tasks,the relationship between cloud tasks and cloud platform energy consumption is established and analyzed on the basis of the multidimensional attributes of cloud tasks. Furthermore,a three-way clustering algorithm of cloud tasks is proposed for saving energy. In the algorithm,f irst,t he cloud tasks are classified into three categories according to the content properties of the cloud tasks and resources respectively. Next,cloud tasks and cloud resources are clustered according to their computation characteristics（ e. g. computation-intensive,data-intensive）. Subsequently,greedy scheduling is performed. The simulation results showthat the proposed algorithm can significantly reduce the energy cost and improve resources utilization,compared with the general greedy scheduling algorithm.展开更多
Typhoon-induced heavy rains are mostly studied from the viewpoint of upper-level westerly troughs. It is worthwhile to probe into a case where the rain is caused by tropical cyclone system, which is much heavier. Duri...Typhoon-induced heavy rains are mostly studied from the viewpoint of upper-level westerly troughs. It is worthwhile to probe into a case where the rain is caused by tropical cyclone system, which is much heavier. During August 3 ~ 5, 1996, an unusually heavy rainstorm happened in the southwest of Hebei province. It was caused by 3 mesoscale convective cloud clusters on the periphery of a tropical cyclone other than the direct effects of a westerly trough. Generating in a weak baroclinic environment that is unstable with high energy, the cloud clusters were triggered off for development by unstable ageostrophic gravity waves in the low-level southeast jet stream on the periphery of the typhoon. There was a vertical circulation cell with horizontal scale close to 1000 km between the rainstorm area and westerly trough in northeast China. As shown in a computation of the Q vector of frontogenesis function, the circulation cell forms a mechanism of transforming energy between the area of interest and the westerly trough system farther away in northeast China. Study of water vapor chart indicates that high-latitude troughs in the northeast portion of the rain migrate to the southeast to enhance anti-cyclonic divergence in upper-level convection over the area of heavy rain and cause rain clusters, short-lived otherwise, to develop vigorously. It is acting as an amplifier in this case of unusually strong process of rain.展开更多
对于广域网下的文件传输和管理,云存储系统提供Web Service API、基于文件的API、基于Block的API和其他的API,通常需要在客户端安装特定程序调用这些API实现云存储功能,测试发现如果多人同时访问,传输文件失败率较高。设计了基于Web Ser...对于广域网下的文件传输和管理,云存储系统提供Web Service API、基于文件的API、基于Block的API和其他的API,通常需要在客户端安装特定程序调用这些API实现云存储功能,测试发现如果多人同时访问,传输文件失败率较高。设计了基于Web Service、HTTP和Flash技术的文件传输协议VCFTP,开发了基于虚拟主机集群的云存储系统VCloudStorage。首先建立SaaS服务模型,利用HTTP数据流存储技术,建立虚拟主机存储接口;接着建立虚拟主机传输能力、存储能力和价格能力数学模型,结合用户的传输请求建立文件传输整数规划数学模型及最优化算法,最终以此为基础设计了文件传输控制协议VCFTP。VCFTP利用Flash跨平台和富客户端技术特点,无需在客户端部署其他程序;授权的用户根据传输请求、存储要求、服务水平和当前虚拟主机状态等条件,以传输能力最优化的方式进行文件传输。实验结果表明VCFTP具有较高的性能和稳定性,VCloudStorage总吞吐量、平均传输率和文件传输成功率均优于微软SkyDrive存储、腾讯QQ邮箱存储和单虚拟主机存储。本文提出的VCFTP增强了文件传输性能和稳定性,是提高广域网网络存储系统性能的一条有效途径。展开更多
Air pollution caused by fine dust is a big problem all over the world and fine dust has a fatal impact on human health.But there are too few fine dust measuring stations and the installation cost of fine dust measurin...Air pollution caused by fine dust is a big problem all over the world and fine dust has a fatal impact on human health.But there are too few fine dust measuring stations and the installation cost of fine dust measuring station is very expensive.In this paper,we propose Cloud-based air pollution information system using R.To measure fine dust,we have developed an inexpensive measuring device and studied the technique to accurately measure the concentration of fine dust at the user’s location.And we have developed the smartphone application to provide air pollution information.In our system,we provide collected data based analytical results through effective data modeling.Our system provides information on fine dust value and action tips through the air pollution information application.And it supports visualization on the map using the statistical program R.The user can check the fine dust statistics map and cope with fine dust accordingly.展开更多
基金Supported by the Meteorological Science and Technology Innovation Project of North China(HBXM202415)Research Project of the Meteorological Bureau of Inner Mongolia Autonomous Region(nmqxkjcx202311).
文摘Based on the conventional observation data,daily reanalysis data from NCAR/NCEP,and TBB data derived from FY-2G infrared cloud images in April 2018,a heavy snowfall weather process in central Inner Mongolia from April 4 to 6 in 2018 was analyzed.The results show that the low trough at 500 hPa,the southerly wind jet stream at 700 hPa,and the inverted trough on the ground were the main influencing systems causing this blizzard.The transportation of warm and humid air by the southerly wind jet stream at 700 hPa and intense water vapor convergence provided sufficient water vapor conditions for the blizzard,and the moist layer in the blizzard area was deep.The low-level MPV in the blizzard area was<0,and the atmosphere was in a conditional symmetric instability state.The coupling of the upper and lower-level jets induced strong ascending motion.With the invasion of cold air,a low-level cold pad was formed,so that the warm and humid air tilted upward.The secondary circulation updraft triggered by the wet Q vector system released the conditional symmetric instability energy,so that the sloping motion was more intense,and the heavy snowfall appeared.Meanwhile,there was a good correspondence relationship between the blizzard area and the large-value area of low-level wet Q vector divergence.The mesoscale cloud clusters continuously generating,merging,and moving eastward in Hetao area were the direct cause of this blizzard,and the TBB of the cloud clusters was≤-56℃.The blizzard happened in the the edge gradient and large-value area of TBB.
文摘In this paper, time and space distribution regularity of meso-scale heavy rains in five selected typhoons which landed at Fujian from 1996 to 1998 has been analyzed. Besides, with hourly digitized satellite infrared imagery, the features of the mesoscale are revealed for the genesis and evolution of mesoscale convective systems in typhoons. It indicates that the intensity of mesoscale storms is closely connected with the temperature and the area of the coldest cloud cluster. The heavy rainfall usually emerges on the eastern side of the mesoscale convective cloud clusters, where the cloud mass is developing and with a dense gradient and big curvature of isoline of the cloud top temperature.
基金Supported by the National Natural Science Foundation of China(42475015,41930972,and 42005141)。
文摘Activities of tropical cyclones(TCs)over the Bay of Bengal(BoB)often exert appreciable influences on precipitation in China,but how and to what extent these influences operate remain unclear.This study utilizes the International Best Track Archive for Climate Stewardship(IBTrACS)dataset and infrared satellite images from Japan during1996-2021 to analyze the cloud system structure patterns associated with BoB TCs(excluding tropical depressions)and their impact on China rainfall.A fuzzy c-means clustering method was employed to classify TC cloud clusters into three morphological types:Type“6”(T6)and Type“9”(T9),with cloud distributions predominantly located north(south)of the TC center;and type“symmetry”(TSM),with relatively balanced cloud distributions on both sides.The results indicate that T6(41.3%)occurs most frequently in autumn,T9(31.2%)peaks in early summer,and TSM(27.5%)also shows a slight preference for autumn.Distinct circulation features are associated with each type.At 500 hPa over the Qinghai-Xizang Plateau(QXP),T6 is associated with the southern branch trough,T9 with straight westerlies,and TSM with a ridge.At 200 hPa,both centers of T6 and TSM are located at the periphery of the South Asian high(SAH),with enhanced upper-level divergence outflows,resulting in northward extension of cloud clusters under the influence of the westerly jet.In contrast,T9 TCs are embedded within the SAH,where weaker divergence outflows restrict northward cloud development.All three types are characterized by a column-integrated water vapor channel extending from the BoB to southern China,with T9 exhibiting the strongest moisture transport to China.Precipitation analyses reveal that all three types contribute to rainfall in Yunnan Province and the Guangxi Zhuangzu Zizhiqu.Moreover,T6 produces heavier rainfall in southern Xizang Zizhiqu(abbreviated as Xizang hereafter),T9 in Yunnan Province,and TSM in Sichuan Province and Xizang.Remote precipitation induced by TC longdistance moisture transport also exhibits distinct patterns:under T6,high-rainfall areas are widely distributed across southwestern China and parts of southern China;under T9,heavy rainfall is concentrated in southern China;and under TSM,heavy rainfall is mainly confined to Guangdong and Jiangxi provinces.These results provide useful insights for precipitation forecasting in China based on the cloud cluster patterns of the BoB TCs.
基金Supported by the National Natural Science Foundation of China(41620104009 and 41975058)Science and Technology Funds of Hubei Meteorological Bureau(2022Y25 and 2022Z02)+3 种基金Joint Open Project of Key Laboratory of Meteorological Disaster,Ministry of Education&Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science&Technology(KLME202106)in part supported by the U.S.National Science Foundation(AGS-2032532)NOAA(NA20OAR4310380)
文摘Eastward-moving cloud clusters from the Tibetan Plateau(TP)often trigger heavy rainfall events in the Yangtze River basin in summer.Forecasting these events in an operational environment remains a challenging task.Here,dynamical diagnosis and a Lagrangian trajectory model are used to analyze the background atmospheric circulation,maintenance mechanism,and moisture transport of two Meiyu front rainstorms(MYFR)during 30 June-2 July 2016 and 17-19 June 2018 associated with eastward-moving cloud clusters from the TP.It is shown that in both cases heavy rainfall is characterized by semi-continuous rainbelts extending from the eastern TP to the Yangtze River valleys with eastward-spreading convective clouds weakening and strengthening alternately from the eastern TP to downstream regions.Following the track of positive water vapor advection,centers of positive vorticity propagate downstream through the Sichuan basin.The baroclinic thermodynamic–dynamical interaction and the barotropic nonequilibrium force work against each other in the development of the MYFR.Specifically,during the early stage of precipitation development,the barotropic non-equilibrium force dominates,while during the period of heavy precipitation the baroclinic thermodynamic-dynamical interaction dominates.The convergence associated with the baroclinic thermodynamic-dynamical interaction guarantees the persistence of heavy precipitation.Compared to the climate mean state(1988-2018),both MYFR events associated with eastward-moving cloud clusters from the eastern TP are characterized by increased moisture transport from the southwest.One of the major paths of moisture transport in both cases is along the south side of the TP,directly connected to the eastward movement of cloud clusters.
基金National Natural Science Foundation of China, N0.40971102 Knowledge Innovation Project of the Chinese Academy of Sciences, No. KZCX2-YW-322 Special Grant for Postgraduates＇ Scientific Innovation and So- cial Practice in 2008
文摘Traditional spatial clustering methods have the disadvantage of ＂hardware division＂, and can not describe the physical characteristics of spatial entity effectively. In view of the above, this paper sets forth a general multi-dimensional cloud model, which describes the characteristics of spatial objects more reasonably according to the idea of non-homogeneous and non-symmetry. Based on infrastructures＇ classification and demarcation in Zhanjiang, a detailed interpretation of clustering results is made from the spatial distribution of membership degree of clustering, the comparative study of Fuzzy C-means and a coupled analysis of residential land prices. General multi-dimensional cloud model reflects the integrated char- acteristics of spatial objects better, reveals the spatial distribution of potential information, and realizes spatial division more accurately in complex circumstances. However, due to the complexity of spatial interactions between geographical entities, the generation of cloud model is a specific and challenging task.
基金Supported by the Harbin Technology Bureau Youth Talented Project(2014RFQXJ073)China Postdoctoral Fund Projects(2014M561330)
文摘Cloud computing has developed as an important information technology paradigm which can provide on-demand services. Meanwhile,its energy consumption problem has attracted a grow-ing attention both from academic and industrial communities. In this paper,from the perspective of cloud tasks,the relationship between cloud tasks and cloud platform energy consumption is established and analyzed on the basis of the multidimensional attributes of cloud tasks. Furthermore,a three-way clustering algorithm of cloud tasks is proposed for saving energy. In the algorithm,f irst,t he cloud tasks are classified into three categories according to the content properties of the cloud tasks and resources respectively. Next,cloud tasks and cloud resources are clustered according to their computation characteristics（ e. g. computation-intensive,data-intensive）. Subsequently,greedy scheduling is performed. The simulation results showthat the proposed algorithm can significantly reduce the energy cost and improve resources utilization,compared with the general greedy scheduling algorithm.
文摘Typhoon-induced heavy rains are mostly studied from the viewpoint of upper-level westerly troughs. It is worthwhile to probe into a case where the rain is caused by tropical cyclone system, which is much heavier. During August 3 ~ 5, 1996, an unusually heavy rainstorm happened in the southwest of Hebei province. It was caused by 3 mesoscale convective cloud clusters on the periphery of a tropical cyclone other than the direct effects of a westerly trough. Generating in a weak baroclinic environment that is unstable with high energy, the cloud clusters were triggered off for development by unstable ageostrophic gravity waves in the low-level southeast jet stream on the periphery of the typhoon. There was a vertical circulation cell with horizontal scale close to 1000 km between the rainstorm area and westerly trough in northeast China. As shown in a computation of the Q vector of frontogenesis function, the circulation cell forms a mechanism of transforming energy between the area of interest and the westerly trough system farther away in northeast China. Study of water vapor chart indicates that high-latitude troughs in the northeast portion of the rain migrate to the southeast to enhance anti-cyclonic divergence in upper-level convection over the area of heavy rain and cause rain clusters, short-lived otherwise, to develop vigorously. It is acting as an amplifier in this case of unusually strong process of rain.
文摘对于广域网下的文件传输和管理,云存储系统提供Web Service API、基于文件的API、基于Block的API和其他的API,通常需要在客户端安装特定程序调用这些API实现云存储功能,测试发现如果多人同时访问,传输文件失败率较高。设计了基于Web Service、HTTP和Flash技术的文件传输协议VCFTP,开发了基于虚拟主机集群的云存储系统VCloudStorage。首先建立SaaS服务模型,利用HTTP数据流存储技术,建立虚拟主机存储接口;接着建立虚拟主机传输能力、存储能力和价格能力数学模型,结合用户的传输请求建立文件传输整数规划数学模型及最优化算法,最终以此为基础设计了文件传输控制协议VCFTP。VCFTP利用Flash跨平台和富客户端技术特点,无需在客户端部署其他程序;授权的用户根据传输请求、存储要求、服务水平和当前虚拟主机状态等条件,以传输能力最优化的方式进行文件传输。实验结果表明VCFTP具有较高的性能和稳定性,VCloudStorage总吞吐量、平均传输率和文件传输成功率均优于微软SkyDrive存储、腾讯QQ邮箱存储和单虚拟主机存储。本文提出的VCFTP增强了文件传输性能和稳定性,是提高广域网网络存储系统性能的一条有效途径。
文摘Air pollution caused by fine dust is a big problem all over the world and fine dust has a fatal impact on human health.But there are too few fine dust measuring stations and the installation cost of fine dust measuring station is very expensive.In this paper,we propose Cloud-based air pollution information system using R.To measure fine dust,we have developed an inexpensive measuring device and studied the technique to accurately measure the concentration of fine dust at the user’s location.And we have developed the smartphone application to provide air pollution information.In our system,we provide collected data based analytical results through effective data modeling.Our system provides information on fine dust value and action tips through the air pollution information application.And it supports visualization on the map using the statistical program R.The user can check the fine dust statistics map and cope with fine dust accordingly.
