检索结果-南通市图书馆

Efficiently Improving Ensemble Forecasts of warm-sector heavy rainfall over Coastal Southern China: Targeted Assimilation to Reduce the Critical Initial Field Errors

引用

气象学报:英文版 2023年第4期37卷 486-507页

作者： Xinghua BAO Rudi XIA Yali LUO Jian YUE State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences(CAMS)China Meteorological Administration(CMA)Beijing 100081 Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD) Nanjing University of Information Science&TechnologyNanjing 210044 CMA Earth System Modeling and Prediction Centre China Meteorological AdministrationBeijing 100081

warm-sector heavy rainfall events over southern China are difficult to accurately forecast, due in part to inaccurate initial fields in numerical weather prediction models. In order to determine an efficient way of reducing the critical initial field errors, this study conducts and compares two sets of 60-member ensemble forecast experiments of a warm-sector heavy rainfall event over coastal southern China without data assimilation(NODA) and with radar radial velocity data assimilation(RadarDA). Yangjiang radar data, which can provide offshore high-resolution wind field information, were assimilated by using a Weather Research and Forecasting(WRF)-based ensemble Kalman filter(EnKF) system. The results show that the speed and direction errors of the southeasterly airflow in the marine boundary layer over the northern South China Sea may primarily be responsible for the forecast errors in rainfall and convection evolution. Targeted assimilation of radial velocity data from the Yangjiang radar can reduce the critical initial field errors of most members, resulting in improvements to the ensemble forecast. Specifically, RadarDA simulations indicate that radial-velocity data assimilation(VrDA) can directly reduce the initial field errors in wind speed and direction, and indirectly and slightly adjust the initial moisture fields in most members, thereby improving the evolution features of moisture transport during the subsequent forecast period. Therefore, these RadarDA members can better capture the initiation and development of convection and have higher forecast skill for the convection evolution and rainfall. The improvement in the deterministic forecasts of most members results in an improved overall ensemble forecast performance. However, VrDA sometimes results in inappropriate adjustment of the initial wind field,so the forecast skill of a few members decreases rather than increases after VrDA. This suggests that a degree of uncertainty remains about the effect of the WRF-based EnKF system. Moreover, the results

关键词： ensemble forecast targeted assimilation warm-sector heavy rainfall

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 Microphysical Characteristics Between warm-sector and Frontal heavy rainfall in the South of China

引用

Journal of Tropical Meteorology 2023年第1期29卷 87-100页

作者：冯璐胡胜刘显通黎慧琦肖辉李晓惠赖瑞泽林青 Guangzhou Institute of Tropical and Marine Meteorology/Guangdong Provincial Key Laboratory of Regional Numerical Weather Prediction China Meteorological AdministrationGuangzhou 510641 China Jiangmen Meteorological Observatory China Meteorological AdministrationJiangmenGuangdong 529000 China Guangdong Provincial Meteorological Observatory China Meteorological AdministrationGuangzhou 510641 China

During the April-June raining season,warm-sector heavy rainfall(WR) and frontal heavy rainfall(FR) often occur in the south of China,causing natural disasters.In this study,the microphysical characteristics of WR and FR events from 2016 to 2022 are analyzed by using 2-dimensional video disdrometer(2DVD) data in the south of China.The microphysical characteristics of WR and FR events are quite different.Compared with FR events,WR events have higher concentration of D 100 mm h^(-1)) for WR and FR events are also different.Raindrops from C3 contribute the most to the precipitation of WR events,and raindrops from C2 contribute the most to the precipitation of FR events.For C2 and C3,compared with FR events,WR events have higher concentration of D <1 mm and D~3-4.5 mm.Moreover,the shape and slope(μ-A) relationships and the radar reflectivity and rain rate(Z-R) relationships of WR and FR events are quite different in each rain rate class.The investigation of the difference in microphysical characteristics between WR and FR events provide useful information for radar-based quantitative precipitation estimation and numerical prediction.

关键词： warm-sector heavy rainfall frontal heavy rainfall raindrop size distribution(DSD) 2-dimensional video disdrometer(2DVD) the south of 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

Observational and Mechanistic Analysis of a Nighttime warm-sector heavy rainfall Event Within the Subtropical High over the Southeastern Coast of China

引用

Journal of Tropical Meteorology 2023年第4期29卷 448-459页

作者：叶龙彬朱婧谌芸李菲郑林晔 Xiamen Key Laboratory of Straits Meteorology Xiamen 361012 China National Meteorological Centre Beijing 100081 China Fujian Meteorological Observatory Fuzhou 350028 China

In August 2021,a warm-sector heavy rainfall event under the control of the western Pacific subtropical high occurred over the southeastern coast of China.Induced by a linearly shaped mesoscale convective system(MCS),this heavy rainfall event was characterized by localized heavy rainfall,high cumulative rainfall,and extreme rainfall intensity.Using various observational data,this study first analyzed the precipitation features and radar reflectivity evolution.It then examined the role of environmental conditions and the relationship between the ambient wind field and convective initiation(CI).Furthermore,the dynamic lifting mechanism within the organization of the MCS was revealed by em-ploying multi-Doppler radar retrieval methods.Results demonstrated that the linearly shaped MCS,developed under the influence of the subtropical high,was the primary cause of the extreme rainfall event.High temperatures and humidity,coupled with the convergence of low-level southerly winds,established the environmental conditions for MCS develop-ment.The superposition of the convergence zone generated by the southerly winds in the boundary layer(925-1000 hPa)and the divergence zone in the lower layer(700-925 hPa)supplied dynamic lifting conditions for CI.Additionally,a long-term shear line(southerly southwesterly)offered favorable conditions for the organization of the linearly shaped MCS.The combined effects of strengthening low-level southerly winds and secondary circulation in mid-upper levels were influential factors in the development and maintenance of the linearly shaped MCS.

关键词： linearly shaped MCS warm-sector heavy rainfall convergence/divergence secondary circulation

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 Microphysical Characteristics of warm-sector,Frontal and Shear-line heavy rainfall During the Pre-summer Rainy Season in South China

引用

Journal of Tropical Meteorology 2023年第2期29卷 204-215页

作者：夏丰刘显通胡胜黎慧琦饶晓娜林青肖辉冯璐赖睿泽 Guangzhou Institute of Tropical and Marine Meteorology China Meteorological AdministrationGuangzhou 510641 China Guangdong Meteorological Observatory China Meteorological AdministrationGuangzhou 510641 China

warm-sector heavy rainfall(WR),shear-line heavy rainfall(SR),and frontal heavy rainfall(FR)are three types of rainfall that frequently occur during the pre-summer rainy season in south China.In this research,we investigated the differences in microphysical characteristics of heavy rainfall events during the period of 10-15 May 2022 based on the combined observations from 11 S-band polarimetric radars in south China.The conclusions are as follows:(1)WR has the highest radar echo top height,the strongest radar echo at all altitudes,the highest lightning density,and the most active ice-phase process,which suggests that the convection is the most vigorous in the WR,moderate in the FR,and the weakest in the SR.(2)Three types of rainfall are all marine-type precipitation,the massweighted mean diameter(Dm,mm)and the intercept parameter(Nw,mm^(-1) m^(-3))of the raindrops in the WR are the largest.(3)The WR possesses the highest proportion of graupel compared with the FR and SR,and stronger updrafts and more abundant water vapor supply may lead to larger raindrops during the melting and collision-coalescence processes.(4)Over all the heights,liquid and ice water content in the WR are higher than those in the SR and FR,the ratio of ice to liquid water content in the WR is as high as 27%when ZH exceeds 50 dBZ,definitely higher than that in the SR and FR,indicating that the active ice-phase process existing in the WR is conducive to the formation of heavy rainfall.

关键词： microphysical characteristic S-band polarimetric radar warm-sector heavy rainfall frontal heavy rainfall shear-line heavy rainfall

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

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

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：