检索结果-南通市图书馆

Mesoscale Analysis of a Heavy Rainfall Event Along the Huaihe River Valley During 8-9 July 2007

Acta meteorologica Sinica 2010年第3期24卷 365-379页

作者：张小玲矫梅燕陈涛 national meteorological center China Meteorological Administration china meteorological administration

During 8-9 July 2007,several successively developed rainstorms along the Meiyu front produced heavy rainfall in the Huaihe River Valley,which led to the most catastrophic flooding in this region since 195.. Through mesoscale analysis of both conventional and intensive observations from upper air and surface stations,automatic weather stations,Doppler radars,and the FY-2C satellite,the current study examines the developing style and environmental conditions of the mesoscale convective systems（MCSs） that led to the development of the rainstorms. Our analysis showed that this event went through three *** first phase of the heavy rainfall （PhaseⅠ） was caused by a meso-α-scale wind shear in the lower troposphere during 0200-1700 BT（Beijing Time） 8 ***Ⅱwas characterized by a reduction in rain rate and the formation of a low-level vortex between 1700 BT 8 and 0200 BT 9 *** PhaseⅢ,the well-organized mature meso-a-scale low-level vortex brought about intensified rains during 0200-0800 BT 9 *** and radar observations showed a backward development of MCSs（new convective cells were generated at the back of the system） in PhaseⅠ,a forward development in PhaseⅢ,and a spiral organization of the convective lines in PhaseⅡ. The heavy rainstorm systems were initiated continuously along a surface mesoscale dew-point front with a horizontal scale of～300 km（as part of the Meiyu front） in the upper reaches of the Huaihe River Valley near Fuyang City,Anhui Province and then gradually decayed in the middle and lower *** is hypothesized that lifting by strong low-level convergence is sufficient to trigger convection in the high CAPE（convective available potential energy） environment.

关键词： rainstorm mesoscale convective system(MCS) wind shear low-level vortex

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Comparison of the Global Energy Cycle between Chinese Reanalysis Interim and ECMWF Reanalysis

引用

Journal of meteorological Research 2019年第3期33卷 563-575页

作者： Bin ZHAO Bo ZHANG Chunxiang SHI Jingwei LIU Lipeng JIANG national meteorological center China Meteorological Administration Beijing 100081 china meteorological administration Numerical Weather Prediction center Beijing 100081 national meteorological Information center China Meteorological Administration Beijing 100081

The global energy cycle is a diagnostic metric widely used to gauge the quality of datasets. In this paper, the "Mixed Space-Time Domain" method for diagnosis of energy cycle is evaluated by using newly developed datasets-the Chinese Reanalysis Interim (CRAI) and ECMWF Reanalysis version 5.(ERA5., over a 7-yr period (2010-16) on seasonal and monthly timescales. The results show that the energy components calculated from the two reanalysis datasets are highly consistent;however, some components in the global energy integral from CRAI are slightly larger than those from ERA5. The main discrepancy in the energy components stems from the conversion of baroclinic process, whereas the dominant difference originates from the conversion from stationary eddy available potential energy to stationary eddy kinetic energy (CES), which is caused by systematic differences in the temperature and vertical velocity in low-mid latitudes of the Northern Hemisphere and near the Antarctic, where there exist complex terrains. Furthermore, the monthly analysis reveals that the general discrepancy in the temporal variation between the two datasets also lie mainly in the CES as well as corresponding generation and dissipation rates.

关键词： global energy cycle transient waves conversion terms Chinese Reanalysis Interim (CRAI) ECMWF Reanalysis version 5 (ERA5.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Development of a Global Historic Monthly Mean Precipitation Dataset

引用

Journal of meteorological Research 2016年第2期30卷 217-231页

作者：杨溯徐文慧许艳李庆祥 national meteorological Information center China Meteorological Administration

Global historic precipitation dataset is the base for climate and water cycle *** have been several global historic land surface precipitation datasets developed by international data centers such as the US national Climatic Data center(NCDC),European Climate Assessment & Dataset project team,Met Office,etc.,but so far there are no such datasets developed by any research institute in *** addition,each dataset has its own focus of study region,and the existing global precipitation datasets only contain sparse observational stations over china,which may result in uncertainties in East Asian precipitation *** order to take into account comprehensive historic information,users might need to employ two or more ***,the non-uniform data formats,data units,station IDs,and so on add extra difficulties for users to exploit these *** this reason,a complete historic precipitation dataset that takes advantages of various datasets has been developed and produced in the national meteorological Information center of *** observations from 12 sources are aggregated,and the data formats,data units,and station IDs are *** stations with the same ID are identified,with duplicated observations *** test,correlation coefficient test,significance t-test at the95.confidence level,and significance F-test at the 95.confidence level are conducted first to ensure the data *** those datasets that satisfy all the above four criteria are integrated to produce the china meteorological administration global precipitation(CGP) historic precipitation dataset version *** contains observations at 31 thousand stations with 1.87 x 107 data records,among which 415. time series of precipitation are longer than 100 *** dataset plays a critical role in climate research due to its advantages in large data volume and high density of station network,compared to other *** the Penalized Maximal

关键词： global precipitation observation historic data

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Development and Application of an Atmospheric-HydrologicHydraulic Flood Forecasting Model Driven by TIGGE Ensemble Forecasts

引用

Acta meteorologica Sinica 2012年第1期26卷 93-102页

作者：包红军赵琳娜 Public meteorological Service center China Meteorological Administration national meteorological center China Meteorological Administration

A coupled atmospheric-hydrologic-hydraulic ensemble flood forecasting model, driven by The Observing System Research and Predictability Experiment （THORPEX） Interactive Grand Global Ensemble （TIGGE） data, has been developed for flood forecasting over the Huaihe River. The incorporation of numerical weather prediction （NWP） information into flood forecasting systems may increase forecast lead time from a few hours to a few days. A single NWP model forecast from a single forecast center, however, is insufficient as it involves considerable non-predictable uncertainties and leads to a high number of false alarms. The availability of global ensemble NWP systems through TIGGE offers a new opportunity for flood forecast. The Xinanjiang model used for hydrological rainfall-runoff modeling and the one-dimensional unsteady flow model applied to channel flood routing are coupled with ensemble weather predictions based on the TIGGE data from the Canadian meteorological Centre （CMC）, the European Centre for Medium-Range Weather Forecasts （ECMWF）, the UK Met Office （UKMO）, and the US national centers for Environmental Prediction （NCEP）. The developed ensemble flood forecasting model is applied to flood forecasting of the 2007 flood season as a test case. The test case is chosen over the upper reaches of the Huaihe River above Lutaizi station with flood diversion and retarding areas. The input flood discharge hydrograph from the main channel to the flood diversion area is estimated with the fixed split ratio of the main channel discharge. The flood flow inside the flood retarding area is calculated as a reservoir with the water balance method. The Muskingum method is used for flood routing in the flood diversion area. A probabilistic discharge and flood inundation forecast is provided as the end product to study the potential benefits of using the TIGGE ensemble forecasts. The results demonstrate satisfactory flood forecasting with clear signals of probability of floods up to a f

关键词： ensemble flood forecast TIGGE ensemble predictions Xinanjiang model one-dimensionalunsteady flow model flood diversion and retarding Huaihe River

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Building Morphological Characteristics and Their Effect on the Wind in Beijing

引用

Advances in Atmospheric Sciences 2009年第6期26卷 1115-1124页

作者：苗世光李萍阳王晓云 Institute of Urban Meteorology China Meteorological Administration national meteorological center China Meteorological Administration Department of Integrated Observations China Meteorological Administration

An urban boundary layer model （UBLM） is improved by incorporating the effect of buildings with a sectional drag coefficient and a height-distributed canopy drag length scale. The improved UBLM is applied to simulate the wind fields over three typical urban blocks over the Beijing area with different height-towidth ratios. For comparisons, the wind fields over the same blocks are simulated by an urban sub-domain scale model resolving the buildings explicitly. The wind fields simulated from the two different methods are in good agreement. Then, two-dimensional building morphological characteristics and urban canopy parameters for Beijing are derived from detailed building height data. Finally, experiements are conducted to investigate the effect of buildings on the wind field in Beijing using the improved UBLM.

关键词： building morphological characteristics urban boundary layer model urban canopy model

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Advances in Severe Convection Research and Operation in china

引用

Journal of meteorological Research 2020年第2期34卷 189-217页

作者： Xiaoding YU Yongguang ZHENG china meteorological administration Training center Beijing 100081 national meteorological center China Meteorological AdministrationBeijing 100081

This article reviews the advances in severe convection research and operation in china during the past several *** favorable synoptic situations for severe convective weather(SCW),the major organization modes of severe convective storms(SCSs),the favorable environmental conditions and characteristics of weather radar echoes and satellite images of SCW and SCSs,and the forecasting and nowcasting techniques of SCW,are *** a whole,Chinese scientists have achieved a profound understanding of the synoptic patterns,organization,and evolution characteristics of SCW from radar and satellite observations,and the mechanisms of different types of convective weather in ***,in-depth understanding of the multiple types of convection triggers,along with the environmental conditions,structures and organization modes,and maintenance mechanisms of supercell storms and squall lines,has been *** organization modes and climatological distributions of mesoscale convective systems and different types of SCW,and the multiscale characteristics and formation mechanisms of large hail,tornadoes,downbursts,and damaging convective wind gusts based on radar,satellite,and lightning observations,as well as the related features from damage surveys,are *** terms of operational applications,different types of identification and mesoanalysis techniques,and various forecasting and nowcasting techniques using methods such as the"ingredients-based"and deep learning algorithms,have been *** a result,the performance of operational SCW forecasts in china has been significantly improved.

关键词： severe convective weather(SCW) forecasting and nowcasting research and operation advances con temporary china

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Changing Trends of Daily Temperature Extremes with Different Intensities in china

引用

Acta meteorologica Sinica 2012年第4期26卷 399-409页

作者：王遵娅丁一汇张强宋亚芳 national Climate center China Meteorological Administration national Climate center China Meteorological Administration china meteorological administration

By comparing two sets of quality-controlled daily temperature observation data with and without the inhomogeneity test and adjustment from 65. stations in china during 195. 2004 and 195.-2010, impacts of inhomogeneity on changing trends of four percentile temperature extreme indices, including occurrences of cold days, cold nights, warm days, and warm nights with varying intensities, were discussed. It is found that the inhomogeneity affected the long-term trends averaged over extensive regions limitedly. In order to minimize the inhomogeneity impact, the 83 stations identified with obvious inhomogeneity impacts were removed, and an updated analysis of changing trends of the four temperature extreme indices with varying intensities during 195. 2010 was conducted. The results show that annual occurrences of both cold nights and cold days decreased greatly while those of warm nights and warm days increased significantly during the recent 20 years. The more extreme the event is, the greater the magnitude of changing trends for the temperature extreme index is. An obvious increasing trend was observed in annual occurrences of cold days and cold nights in the recent four years. The magnitude of changing trends of warm extreme indices was greater than that of cold extreme indices, and it was greater in northern china than in southern china. Trends for summer occurrence of cold days were not significant. Decreasing trends of occurrences of both cold nights and cold days were the greatest in December, January, and February （DJF） but the least in June, July, and August （JJA）, while increasing trends of warm nights were the greatest in JJA. Cold nights significantly decreased from 195. to 1990, and then the decreasing trend considerably weakened. The decreasing trend also showed an obvious slowdown in recent years for occurrence of cold days. However, increasing trends of warm nights and warm days both have been accelerated continuously since the recent decades. Further analy

关键词： temperature extremes cold nights cold days warm nights warm days changing trend

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

气溶胶对降水影响的现象和机制

引用

Science Bulletin 2024年第10期69卷 1569-1580页

作者：赵传峰孙悦杨杰李杰峰周月杨以坤范昊赵辛 Department of Atmospheric and Oceanic Sciences School of Physicsand China Meteorological Administration Tornado Key LaboratoryPeking UniversityBeijing 100871China Institute of Carbon Neutrality Peking UniversityBeijing 100871China Faculty of Geographical Science Beijing Normal UniversityBeijing 100875China School of Environment Beijing Normal UniversityBeijing 100875China

Aerosols greatly influence precipitation characteristics,thereby impacting the regional climate and human *** an indispensable factor for cloud formation and a critical radiation budget regulator,aerosols can affect precipitation intensity,frequency,geographical distribution,area,and ***,discrepancies exist among current studies due to aerosol properties,precipitation types,the vertical location of aerosols and meteorological *** development of technology has driven advances in current research,but understanding the aerosol effects on precipitation remain complex and *** paper revolves around the following topics from the two perspectives of Aerosol-Radiation Interaction(ARI)and Aerosol-Cloud Interaction(ACI):(1)the influence of different vertical locations of absorbing/scattering aerosols on the atmospheric thermal structure;(2)the fundamental theories of ARI reducing surface wind speed,redistributing water vapour and energy,and then modulating precipitation intensity;(3)different aerosol types(absorbing versus scattering)and aerosol concentrations causing different precipitation diurnal and weekly variations;(4)microphysical processes(cloud water competition,invigoration effect,and evaporation cooling)and observational evidence of different effects of aerosols on precipitation intensity,including enhancing,inhibiting,and transitional effects from enhancement to suppression;and(5.how meteorology,water vapor and dynamics influencing the effect of ACI and ARI on *** addition,this review lists the existing issues and future research directions for attaining a more comprehensive understanding of aerosol effects on ***,this review advances our understanding of aerosol effects on precipitation and could guide the improvement of weather and climate models to predict complex aerosol-precipitation interactions more accurately.

关键词： Aerosol Precipitation Aerosol-Radiation Interaction(ARI) Aerosol-Cloud Interaction(ACI) Mechanism

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

CNN demodulation model with cascade parallel crossing for CPM signals

引用

The Journal of china Universities of Posts and Telecommunications 2024年第3期31卷 30-42页

作者： Yang Jiachen Duan Ruifeng Li Chengju School of Information Science and Technology Beijing Forestry UniversityBeijing 100083China Engineering Research center for Forestry-Oriented Intelligent Information Processing of national Forestry and Grassland administration Beijing 100083China

The continuous phase modulation(CPM)technique is widely used in range telemetry due to its high spectral efficiency and power ***,the demodulation performance of the traditional maximum likelihood sequence detection(MLSD)algorithm significantly deteriorates in non-ideal synchronization or fading *** address this issue,this work proposes a convolutional neural network(CNN)called the cascade parallel crossing network(CPCNet)to enhance the robustness of CPM signals *** CPCNet model employs a multiple parallel structure and feature fusion to extract richer features from CPM *** approach constructs feature maps at different levels,resulting in a more comprehensive training of the model and improved demodulation *** results show that under Gaussian channel,the proposed CPCNet achieves the same bit error rate(BER)performance as MLSD method when there is no timing error,but with 1/4 symbol period timing error,the proposed method has 2 dB demodulation gain compared with CNN and convolutional long short-term memory deep neural network(CLDNN).In addition,under Rayleigh channel,the BER of the proposed method is reduced by 5.-87%compared to that of MLSD in the wide signal-to-noise ratio(SNR)region.

关键词： continuous phase modulation(CPM) convolutional neural network(CNN) maximum likelihood sequence detection(MLSD) Rayleigh fading timing error

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Comparison of Different Order Adams-Bashforth Methods in an Atmospheric General Circulation Model

引用

Acta meteorologica Sinica 2011年第6期25卷 754-764页

作者：赵滨张博 national meteorological center China Meteorological Administration

The Asselin-Robert time As an attractive alternative filter used in the leaptYog scheme does degrade the accuracy of calculations. to leapfrog time differencing, the second-order Adams-Bashforth method is not subject to time splitting instability and keeps excellent calculation accuracy. A second-order Adams- Bashforth model has been developed, which represents better stability, excellent convergence and improved simulation of prognostic variables. Based on these results, the higher-order Adams-Bashforth methods are developed on the basis of NCAR （national center for Atmospheric Research） CAM 3.1 （Community Atmosphere Model 3.1） and the characteristics of dynamical cores are analyzed in this paper. By using Lorenz nonlinear convective equations, the filtered leapfrog scheme shows an excellent pattern for eliminating 2At wave solutions after 20 steps but represents less computational solution accuracy. The fourth-order Adams- Bashforth method is closely converged to the exact solution and provides a reference against which other methods may be compared. Thus, the Adams-Bashforth methods produce more accurate and convergent solution with differencing order increasing. The Held-Suarez idealized test is carried out to demonstrate that all methods have similar climate states to the results of many other global models for long-term integration. Besides, higher-order methods perform better in mass conservation and exhibit improvement in simulating tropospheric westerly jets, which is likely equivalent to the advantages of increasing horizontal resolutions. Based on the idealized baroclinic wave test, a better capability of the higher-order method in maintaining simulation stability is convinced. Furthermore, after the baroclinic wave is triggered through overlaying the steady-state initial conditions with the zonal perturbation, the higher-order method has a better ability in the simulation of baroclinic wave perturbation.

关键词： Adams-Bashforth method Lorenz nonlinear convection equations baroclinic wave test am-plitude accuracy

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：